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1 #include <u.h>
2 #include <libc.h>
3 #include <mp.h>
4 #include <libsec.h>
5
6 /*=============================================================*/
7 /*  general ASN1 declarations and parsing
8  *
9  *  For now, this is used only for extracting the key from an
10  *  X509 certificate, so the entire collection is hidden.  But
11  *  someday we should probably make the functions visible and
12  *  give them their own man page.
13  */
14 typedef struct Elem Elem;
15 typedef struct Tag Tag;
16 typedef struct Value Value;
17 typedef struct Bytes Bytes;
18 typedef struct Ints Ints;
19 typedef struct Bits Bits;
20 typedef struct Elist Elist;
21
22 /* tag classes */
23 #define Universal 0
24 #define Context 0x80
25
26 /* universal tags */
27 #define BOOLEAN 1
28 #define INTEGER 2
29 #define BIT_STRING 3
30 #define OCTET_STRING 4
31 #define NULLTAG 5
32 #define OBJECT_ID 6
33 #define ObjectDescriptor 7
34 #define EXTERNAL 8
35 #define REAL 9
36 #define ENUMERATED 10
37 #define EMBEDDED_PDV 11
38 #define UTF8String 12
39 #define SEQUENCE 16             /* also SEQUENCE OF */
40 #define SETOF 17                                /* also SETOF OF */
41 #define NumericString 18
42 #define PrintableString 19
43 #define TeletexString 20
44 #define VideotexString 21
45 #define IA5String 22
46 #define UTCTime 23
47 #define GeneralizedTime 24
48 #define GraphicString 25
49 #define VisibleString 26
50 #define GeneralString 27
51 #define UniversalString 28
52 #define BMPString 30
53
54 struct Bytes {
55         int     len;
56         uchar   data[];
57 };
58
59 struct Ints {
60         int     len;
61         int     data[];
62 };
63
64 struct Bits {
65         int     len;            /* number of bytes */
66         int     unusedbits;     /* unused bits in last byte */
67         uchar   data[];         /* most-significant bit first */
68 };
69
70 struct Tag {
71         int     class;
72         int     num;
73 };
74
75 enum { VBool, VInt, VOctets, VBigInt, VReal, VOther,
76         VBitString, VNull, VEOC, VObjId, VString, VSeq, VSet };
77 struct Value {
78         int     tag;            /* VBool, etc. */
79         union {
80                 int     boolval;
81                 int     intval;
82                 Bytes*  octetsval;
83                 Bytes*  bigintval;
84                 Bytes*  realval;        /* undecoded; hardly ever used */
85                 Bytes*  otherval;
86                 Bits*   bitstringval;
87                 Ints*   objidval;
88                 char*   stringval;
89                 Elist*  seqval;
90                 Elist*  setval;
91         } u;  /* (Don't use anonymous unions, for ease of porting) */
92 };
93
94 struct Elem {
95         Tag     tag;
96         Value   val;
97 };
98
99 struct Elist {
100         Elist*  tl;
101         Elem    hd;
102 };
103
104 /* decoding errors */
105 enum { ASN_OK, ASN_ESHORT, ASN_ETOOBIG, ASN_EVALLEN,
106                 ASN_ECONSTR, ASN_EPRIM, ASN_EINVAL, ASN_EUNIMPL };
107
108
109 /* here are the functions to consider making extern someday */
110 static Bytes*   newbytes(int len);
111 static Bytes*   makebytes(uchar* buf, int len);
112 static void     freebytes(Bytes* b);
113 static Bytes*   catbytes(Bytes* b1, Bytes* b2);
114 static Ints*    newints(int len);
115 static Ints*    makeints(int* buf, int len);
116 static void     freeints(Ints* b);
117 static Bits*    newbits(int len);
118 static Bits*    makebits(uchar* buf, int len, int unusedbits);
119 static void     freebits(Bits* b);
120 static Elist*   mkel(Elem e, Elist* tail);
121 static void     freeelist(Elist* el);
122 static int      elistlen(Elist* el);
123 static int      is_seq(Elem* pe, Elist** pseq);
124 static int      is_set(Elem* pe, Elist** pset);
125 static int      is_int(Elem* pe, int* pint);
126 static int      is_bigint(Elem* pe, Bytes** pbigint);
127 static int      is_bitstring(Elem* pe, Bits** pbits);
128 static int      is_octetstring(Elem* pe, Bytes** poctets);
129 static int      is_oid(Elem* pe, Ints** poid);
130 static int      is_string(Elem* pe, char** pstring);
131 static int      is_time(Elem* pe, char** ptime);
132 static int      decode(uchar* a, int alen, Elem* pelem);
133 static int      encode(Elem e, Bytes** pbytes);
134 static int      oid_lookup(Ints* o, Ints** tab);
135 static void     freevalfields(Value* v);
136 static mpint    *asn1mpint(Elem *e);
137 static void     edump(Elem);
138
139 #define TAG_MASK 0x1F
140 #define CONSTR_MASK 0x20
141 #define CLASS_MASK 0xC0
142 #define MAXOBJIDLEN 20
143
144 static int ber_decode(uchar** pp, uchar* pend, Elem* pelem);
145 static int tag_decode(uchar** pp, uchar* pend, Tag* ptag, int* pisconstr);
146 static int length_decode(uchar** pp, uchar* pend, int* plength);
147 static int value_decode(uchar** pp, uchar* pend, int length, int kind, int isconstr, Value* pval);
148 static int int_decode(uchar** pp, uchar* pend, int count, int unsgned, int* pint);
149 static int uint7_decode(uchar** pp, uchar* pend, int* pint);
150 static int octet_decode(uchar** pp, uchar* pend, int length, int isconstr, Bytes** pbytes);
151 static int seq_decode(uchar** pp, uchar* pend, int length, int isconstr, Elist** pelist);
152 static int enc(uchar** pp, Elem e, int lenonly);
153 static int val_enc(uchar** pp, Elem e, int *pconstr, int lenonly);
154 static void uint7_enc(uchar** pp, int num, int lenonly);
155 static void int_enc(uchar** pp, int num, int unsgned, int lenonly);
156
157 static void *
158 emalloc(int n)
159 {
160         void *p;
161         if(n==0)
162                 n=1;
163         p = malloc(n);
164         if(p == nil)
165                 sysfatal("out of memory");
166         memset(p, 0, n);
167         setmalloctag(p, getcallerpc(&n));
168         return p;
169 }
170
171 static char*
172 estrdup(char *s)
173 {
174         char *d;
175         int n;
176
177         n = strlen(s)+1;
178         d = emalloc(n);
179         memmove(d, s, n);
180         return d;
181 }
182
183
184 /*
185  * Decode a[0..len] as a BER encoding of an ASN1 type.
186  * The return value is one of ASN_OK, etc.
187  * Depending on the error, the returned elem may or may not
188  * be nil.
189  */
190 static int
191 decode(uchar* a, int alen, Elem* pelem)
192 {
193         uchar* p = a;
194         int err;
195
196         err = ber_decode(&p, &a[alen], pelem);
197         if(err == ASN_OK && p != &a[alen])
198                 err = ASN_EVALLEN;
199         return err;
200 }
201
202 /*
203  * All of the following decoding routines take arguments:
204  *      uchar **pp;
205  *      uchar *pend;
206  * Where parsing is supposed to start at **pp, and when parsing
207  * is done, *pp is updated to point at next char to be parsed.
208  * The pend pointer is just past end of string; an error should
209  * be returned parsing hasn't finished by then.
210  *
211  * The returned int is ASN_OK if all went fine, else ASN_ESHORT, etc.
212  * The remaining argument(s) are pointers to where parsed entity goes.
213  */
214
215 /* Decode an ASN1 'Elem' (tag, length, value) */
216 static int
217 ber_decode(uchar** pp, uchar* pend, Elem* pelem)
218 {
219         int err;
220         int isconstr;
221         int length;
222         Tag tag;
223         Value val;
224
225         memset(pelem, 0, sizeof(*pelem));
226         err = tag_decode(pp, pend, &tag, &isconstr);
227         if(err == ASN_OK) {
228                 err = length_decode(pp, pend, &length);
229                 if(err == ASN_OK) {
230                         if(tag.class == Universal)
231                                 err = value_decode(pp, pend, length, tag.num, isconstr, &val);
232                         else
233                                 err = value_decode(pp, pend, length, OCTET_STRING, 0, &val);
234                         if(err == ASN_OK) {
235                                 pelem->tag = tag;
236                                 pelem->val = val;
237                         }
238                 }
239         }
240         return err;
241 }
242
243 /* Decode a tag field */
244 static int
245 tag_decode(uchar** pp, uchar* pend, Tag* ptag, int* pisconstr)
246 {
247         int err;
248         int v;
249         uchar* p;
250
251         err = ASN_OK;
252         p = *pp;
253         if(pend-p >= 2) {
254                 v = *p++;
255                 ptag->class = v&CLASS_MASK;
256                 if(v&CONSTR_MASK)
257                         *pisconstr = 1;
258                 else
259                         *pisconstr = 0;
260                 v &= TAG_MASK;
261                 if(v == TAG_MASK)
262                         err = uint7_decode(&p, pend, &v);
263                 ptag->num = v;
264         }
265         else
266                 err = ASN_ESHORT;
267         *pp = p;
268         return err;
269 }
270
271 /* Decode a length field */
272 static int
273 length_decode(uchar** pp, uchar* pend, int* plength)
274 {
275         int err;
276         int num;
277         int v;
278         uchar* p;
279
280         err = ASN_OK;
281         num = 0;
282         p = *pp;
283         if(p < pend) {
284                 v = *p++;
285                 if(v&0x80)
286                         err = int_decode(&p, pend, v&0x7F, 1, &num);
287                 else
288                         num = v;
289         }
290         else
291                 err = ASN_ESHORT;
292         *pp = p;
293         *plength = num;
294         return err;
295 }
296
297 /* Decode a value field  */
298 static int
299 value_decode(uchar** pp, uchar* pend, int length, int kind, int isconstr, Value* pval)
300 {
301         int err;
302         Bytes* va;
303         int num;
304         int bitsunused;
305         int subids[MAXOBJIDLEN];
306         int isubid;
307         Elist*  vl;
308         uchar* p;
309         uchar* pe;
310
311         err = ASN_OK;
312         p = *pp;
313         if(length == -1) {      /* "indefinite" length spec */
314                 if(!isconstr)
315                         err = ASN_EINVAL;
316         }
317         else if(p + length > pend)
318                 err = ASN_EVALLEN;
319         if(err != ASN_OK)
320                 return err;
321
322         switch(kind) {
323         case 0:
324                 /* marker for end of indefinite constructions */
325                 if(length == 0)
326                         pval->tag = VNull;
327                 else
328                         err = ASN_EINVAL;
329                 break;
330
331         case BOOLEAN:
332                 if(isconstr)
333                         err = ASN_ECONSTR;
334                 else if(length != 1)
335                         err = ASN_EVALLEN;
336                 else {
337                         pval->tag = VBool;
338                         pval->u.boolval = (*p++ != 0);
339                 }
340                 break;
341
342         case INTEGER:
343         case ENUMERATED:
344                 if(isconstr)
345                         err = ASN_ECONSTR;
346                 else if(length <= 4) {
347                         err = int_decode(&p, pend, length, 0, &num);
348                         if(err == ASN_OK) {
349                                 pval->tag = VInt;
350                                 pval->u.intval = num;
351                         }
352                 }
353                 else {
354                         pval->tag = VBigInt;
355                         pval->u.bigintval = makebytes(p, length);
356                         p += length;
357                 }
358                 break;
359
360         case BIT_STRING:
361                 pval->tag = VBitString;
362                 if(isconstr) {
363                         if(length == -1 && p + 2 <= pend && *p == 0 && *(p+1) ==0) {
364                                 pval->u.bitstringval = makebits(0, 0, 0);
365                                 p += 2;
366                         }
367                         else    /* TODO: recurse and concat results */
368                                 err = ASN_EUNIMPL;
369                 }
370                 else {
371                         if(length < 2) {
372                                 if(length == 1 && *p == 0) {
373                                         pval->u.bitstringval = makebits(0, 0, 0);
374                                         p++;
375                                 }
376                                 else
377                                         err = ASN_EINVAL;
378                         }
379                         else {
380                                 bitsunused = *p;
381                                 if(bitsunused > 7)
382                                         err = ASN_EINVAL;
383                                 else if(length > 0x0FFFFFFF)
384                                         err = ASN_ETOOBIG;
385                                 else {
386                                         pval->u.bitstringval = makebits(p+1, length-1, bitsunused);
387                                         p += length;
388                                 }
389                         }
390                 }
391                 break;
392
393         case OCTET_STRING:
394         case ObjectDescriptor:
395                 err = octet_decode(&p, pend, length, isconstr, &va);
396                 if(err == ASN_OK) {
397                         pval->tag = VOctets;
398                         pval->u.octetsval = va;
399                 }
400                 break;
401
402         case NULLTAG:
403                 if(isconstr)
404                         err = ASN_ECONSTR;
405                 else if(length != 0)
406                         err = ASN_EVALLEN;
407                 else
408                         pval->tag = VNull;
409                 break;
410
411         case OBJECT_ID:
412                 if(isconstr)
413                         err = ASN_ECONSTR;
414                 else if(length == 0)
415                         err = ASN_EVALLEN;
416                 else {
417                         isubid = 0;
418                         pe = p+length;
419                         while(p < pe && isubid < MAXOBJIDLEN) {
420                                 err = uint7_decode(&p, pend, &num);
421                                 if(err != ASN_OK)
422                                         break;
423                                 if(isubid == 0) {
424                                         subids[isubid++] = num / 40;
425                                         subids[isubid++] = num % 40;
426                                 }
427                                 else
428                                         subids[isubid++] = num;
429                         }
430                         if(err == ASN_OK) {
431                                 if(p != pe)
432                                         err = ASN_EVALLEN;
433                                 else {
434                                         pval->tag = VObjId;
435                                         pval->u.objidval = makeints(subids, isubid);
436                                 }
437                         }
438                 }
439                 break;
440
441         case EXTERNAL:
442         case EMBEDDED_PDV:
443                 /* TODO: parse this internally */
444                 if(p+length > pend)
445                         err = ASN_EVALLEN;
446                 else {
447                         pval->tag = VOther;
448                         pval->u.otherval = makebytes(p, length);
449                         p += length;
450                 }
451                 break;
452
453         case REAL:
454                 /* Let the application decode */
455                 if(isconstr)
456                         err = ASN_ECONSTR;
457                 else if(p+length > pend)
458                         err = ASN_EVALLEN;
459                 else {
460                         pval->tag = VReal;
461                         pval->u.realval = makebytes(p, length);
462                         p += length;
463                 }
464                 break;
465
466         case SEQUENCE:
467                 err = seq_decode(&p, pend, length, isconstr, &vl);
468                 if(err == ASN_OK) {
469                         pval->tag = VSeq ;
470                         pval->u.seqval = vl;
471                 }
472                 break;
473
474         case SETOF:
475                 err = seq_decode(&p, pend, length, isconstr, &vl);
476                 if(err == ASN_OK) {
477                         pval->tag = VSet;
478                         pval->u.setval = vl;
479                 }
480                 break;
481
482         case UTF8String:
483         case NumericString:
484         case PrintableString:
485         case TeletexString:
486         case VideotexString:
487         case IA5String:
488         case UTCTime:
489         case GeneralizedTime:
490         case GraphicString:
491         case VisibleString:
492         case GeneralString:
493         case UniversalString:
494         case BMPString:
495                 err = octet_decode(&p, pend, length, isconstr, &va);
496                 if(err == ASN_OK) {
497                         uchar *s;
498                         char *d;
499                         Rune r;
500                         int n;
501
502                         switch(kind){
503                         case UniversalString:
504                                 n = va->len / 4;
505                                 d = emalloc(n*UTFmax+1);
506                                 pval->u.stringval = d;
507                                 s = va->data;
508                                 while(n > 0){
509                                         r = s[0]<<24 | s[1]<<16 | s[2]<<8 | s[3];
510                                         if(r == 0)
511                                                 break;
512                                         n--;
513                                         s += 4;
514                                         d += runetochar(d, &r);
515                                 }
516                                 *d = 0;
517                                 break;
518                         case BMPString:
519                                 n = va->len / 2;
520                                 d = emalloc(n*UTFmax+1);
521                                 pval->u.stringval = d;
522                                 s = va->data;
523                                 while(n > 0){
524                                         r = s[0]<<8 | s[1];
525                                         if(r == 0)
526                                                 break;
527                                         n--;
528                                         s += 2;
529                                         d += runetochar(d, &r);
530                                 }
531                                 *d = 0;
532                                 break;
533                         default:
534                                 n = va->len;
535                                 d = emalloc(n+1);
536                                 pval->u.stringval = d;
537                                 s = va->data;
538                                 while(n > 0){
539                                         if((*d = *s) == 0)
540                                                 break;
541                                         n--;
542                                         s++;
543                                         d++;
544                                 }
545                                 *d = 0;
546                                 break;
547                         }
548                         if(n != 0){
549                                 err = ASN_EINVAL;
550                                 free(pval->u.stringval);
551                         } else 
552                                 pval->tag = VString;
553                         free(va);
554                 }
555                 break;
556
557         default:
558                 if(p+length > pend)
559                         err = ASN_EVALLEN;
560                 else {
561                         pval->tag = VOther;
562                         pval->u.otherval = makebytes(p, length);
563                         p += length;
564                 }
565                 break;
566         }
567         *pp = p;
568         return err;
569 }
570
571 /*
572  * Decode an int in format where count bytes are
573  * concatenated to form value.
574  * Although ASN1 allows any size integer, we return
575  * an error if the result doesn't fit in a 32-bit int.
576  * If unsgned is not set, make sure to propagate sign bit.
577  */
578 static int
579 int_decode(uchar** pp, uchar* pend, int count, int unsgned, int* pint)
580 {
581         int err;
582         int num;
583         uchar* p;
584
585         p = *pp;
586         err = ASN_OK;
587         num = 0;
588         if(p+count <= pend) {
589                 if((count > 4) || (unsgned && count == 4 && (*p&0x80)))
590                         err = ASN_ETOOBIG;
591                 else {
592                         if(!unsgned && count > 0 && count < 4 && (*p&0x80))
593                                 num = -1;       /* set all bits, initially */
594                         while(count--)
595                                 num = (num << 8)|(*p++);
596                 }
597         }
598         else
599                 err = ASN_ESHORT;
600         *pint = num;
601         *pp = p;
602         return err;
603 }
604
605 /*
606  * Decode an unsigned int in format where each
607  * byte except last has high bit set, and remaining
608  * seven bits of each byte are concatenated to form value.
609  * Although ASN1 allows any size integer, we return
610  * an error if the result doesn't fit in a 32 bit int.
611  */
612 static int
613 uint7_decode(uchar** pp, uchar* pend, int* pint)
614 {
615         int err;
616         int num;
617         int more;
618         int v;
619         uchar* p;
620
621         p = *pp;
622         err = ASN_OK;
623         num = 0;
624         more = 1;
625         while(more && p < pend) {
626                 v = *p++;
627                 if(num&0x7F000000) {
628                         err = ASN_ETOOBIG;
629                         break;
630                 }
631                 num <<= 7;
632                 more = v&0x80;
633                 num |= (v&0x7F);
634         }
635         if(p == pend)
636                 err = ASN_ESHORT;
637         *pint = num;
638         *pp = p;
639         return err;
640 }
641
642 /*
643  * Decode an octet string, recursively if isconstr.
644  * We've already checked that length==-1 implies isconstr==1,
645  * and otherwise that specified length fits within (*pp..pend)
646  */
647 static int
648 octet_decode(uchar** pp, uchar* pend, int length, int isconstr, Bytes** pbytes)
649 {
650         int err;
651         uchar* p;
652         Bytes* ans;
653         Bytes* newans;
654         uchar* pstart;
655         uchar* pold;
656         Elem    elem;
657
658         err = ASN_OK;
659         p = *pp;
660         ans = nil;
661         if(length >= 0 && !isconstr) {
662                 ans = makebytes(p, length);
663                 p += length;
664         }
665         else {
666                 /* constructed, either definite or indefinite length */
667                 pstart = p;
668                 for(;;) {
669                         if(length >= 0 && p >= pstart + length) {
670                                 if(p != pstart + length)
671                                         err = ASN_EVALLEN;
672                                 break;
673                         }
674                         pold = p;
675                         err = ber_decode(&p, pend, &elem);
676                         if(err != ASN_OK)
677                                 break;
678                         switch(elem.val.tag) {
679                         case VOctets:
680                                 newans = catbytes(ans, elem.val.u.octetsval);
681                                 freevalfields(&elem.val);
682                                 freebytes(ans);
683                                 ans = newans;
684                                 break;
685
686                         case VEOC:
687                                 if(length == -1)
688                                         goto cloop_done;
689                                 /* no break */
690                         default:
691                                 freevalfields(&elem.val);
692                                 p = pold;
693                                 err = ASN_EINVAL;
694                                 goto cloop_done;
695                         }
696                 }
697 cloop_done:
698                 if(err != ASN_OK){
699                         freebytes(ans);
700                         ans = nil;
701                 }
702         }
703         *pp = p;
704         *pbytes = ans;
705         return err;
706 }
707
708 /*
709  * Decode a sequence or set.
710  * We've already checked that length==-1 implies isconstr==1,
711  * and otherwise that specified length fits within (*p..pend)
712  */
713 static int
714 seq_decode(uchar** pp, uchar* pend, int length, int isconstr, Elist** pelist)
715 {
716         int err;
717         uchar* p;
718         uchar* pstart;
719         uchar* pold;
720         Elist* ans;
721         Elem elem;
722         Elist* lve;
723         Elist* lveold;
724
725         err = ASN_OK;
726         ans = nil;
727         p = *pp;
728         if(!isconstr)
729                 err = ASN_EPRIM;
730         else {
731                 /* constructed, either definite or indefinite length */
732                 lve = nil;
733                 pstart = p;
734                 for(;;) {
735                         if(length >= 0 && p >= pstart + length) {
736                                 if(p != pstart + length)
737                                         err = ASN_EVALLEN;
738                                 break;
739                         }
740                         pold = p;
741                         err = ber_decode(&p, pend, &elem);
742                         if(err != ASN_OK)
743                                 break;
744                         if(elem.val.tag == VEOC) {
745                                 if(length != -1) {
746                                         p = pold;
747                                         err = ASN_EINVAL;
748                                 }
749                                 break;
750                         }
751                         else
752                                 lve = mkel(elem, lve);
753                 }
754                 if(err != ASN_OK)
755                         freeelist(lve);
756                 else {
757                         /* reverse back to original order */
758                         while(lve != nil) {
759                                 lveold = lve;
760                                 lve = lve->tl;
761                                 lveold->tl = ans;
762                                 ans = lveold;
763                         }
764                 }
765         }
766         *pp = p;
767         *pelist = ans;
768         return err;
769 }
770
771 /*
772  * Encode e by BER rules, putting answer in *pbytes.
773  * This is done by first calling enc with lenonly==1
774  * to get the length of the needed buffer,
775  * then allocating the buffer and using enc again to fill it up.
776  */
777 static int
778 encode(Elem e, Bytes** pbytes)
779 {
780         uchar* p;
781         Bytes* ans;
782         int err;
783         uchar uc;
784
785         p = &uc;
786         err = enc(&p, e, 1);
787         if(err == ASN_OK) {
788                 ans = newbytes(p-&uc);
789                 p = ans->data;
790                 err = enc(&p, e, 0);
791                 *pbytes = ans;
792         }
793         return err;
794 }
795
796 /*
797  * The various enc functions take a pointer to a pointer
798  * into a buffer, and encode their entity starting there,
799  * updating the pointer afterwards.
800  * If lenonly is 1, only the pointer update is done,
801  * allowing enc to be called first to calculate the needed
802  * buffer length.
803  * If lenonly is 0, it is assumed that the answer will fit.
804  */
805
806 static int
807 enc(uchar** pp, Elem e, int lenonly)
808 {
809         int err;
810         int vlen;
811         int constr;
812         Tag tag;
813         int v;
814         int ilen;
815         uchar* p;
816         uchar* psave;
817
818         p = *pp;
819         err = val_enc(&p, e, &constr, 1);
820         if(err != ASN_OK)
821                 return err;
822         vlen = p - *pp;
823         p = *pp;
824         tag = e.tag;
825         v = tag.class|constr;
826         if(tag.num < 31) {
827                 if(!lenonly)
828                         *p = (v|tag.num);
829                 p++;
830         }
831         else {
832                 if(!lenonly)
833                         *p = (v|31);
834                 p++;
835                 if(tag.num < 0)
836                         return ASN_EINVAL;
837                 uint7_enc(&p, tag.num, lenonly);
838         }
839         if(vlen < 0x80) {
840                 if(!lenonly)
841                         *p = vlen;
842                 p++;
843         }
844         else {
845                 psave = p;
846                 int_enc(&p, vlen, 1, 1);
847                 ilen = p-psave;
848                 p = psave;
849                 if(!lenonly) {
850                         *p++ = (0x80 | ilen);
851                         int_enc(&p, vlen, 1, 0);
852                 }
853                 else
854                         p += 1 + ilen;
855         }
856         if(!lenonly)
857                 val_enc(&p, e, &constr, 0);
858         else
859                 p += vlen;
860         *pp = p;
861         return err;
862 }
863
864 static int
865 val_enc(uchar** pp, Elem e, int *pconstr, int lenonly)
866 {
867         int err;
868         uchar* p;
869         int kind;
870         int cl;
871         int v;
872         Bytes* bb = nil;
873         Bits* bits;
874         Ints* oid;
875         int k;
876         Elist* el;
877         char* s;
878
879         p = *pp;
880         err = ASN_OK;
881         kind = e.tag.num;
882         cl = e.tag.class;
883         *pconstr = 0;
884         if(cl != Universal) {
885                 switch(e.val.tag) {
886                 case VBool:
887                         kind = BOOLEAN;
888                         break;
889                 case VInt:
890                         kind = INTEGER;
891                         break;
892                 case VBigInt:
893                         kind = INTEGER;
894                         break;
895                 case VOctets:
896                         kind = OCTET_STRING;
897                         break;
898                 case VReal:
899                         kind = REAL;
900                         break;
901                 case VOther:
902                         kind = OCTET_STRING;
903                         break;
904                 case VBitString:
905                         kind = BIT_STRING;
906                         break;
907                 case VNull:
908                         kind = NULLTAG;
909                         break;
910                 case VObjId:
911                         kind = OBJECT_ID;
912                         break;
913                 case VString:
914                         kind = UniversalString;
915                         break;
916                 case VSeq:
917                         kind = SEQUENCE;
918                         break;
919                 case VSet:
920                         kind = SETOF;
921                         break;
922                 }
923         }
924         switch(kind) {
925         case BOOLEAN:
926                 if(is_int(&e, &v)) {
927                         if(v != 0)
928                                 v = 255;
929                          int_enc(&p, v, 1, lenonly);
930                 }
931                 else
932                         err = ASN_EINVAL;
933                 break;
934
935         case INTEGER:
936         case ENUMERATED:
937                 if(is_int(&e, &v))
938                         int_enc(&p, v, 0, lenonly);
939                 else {
940                         if(is_bigint(&e, &bb)) {
941                                 if(!lenonly)
942                                         memmove(p, bb->data, bb->len);
943                                 p += bb->len;
944                         }
945                         else
946                                 err = ASN_EINVAL;
947                 }
948                 break;
949
950         case BIT_STRING:
951                 if(is_bitstring(&e, &bits)) {
952                         if(bits->len == 0) {
953                                 if(!lenonly)
954                                         *p = 0;
955                                 p++;
956                         }
957                         else {
958                                 v = bits->unusedbits;
959                                 if(v < 0 || v > 7)
960                                         err = ASN_EINVAL;
961                                 else {
962                                         if(!lenonly) {
963                                                 *p = v;
964                                                 memmove(p+1, bits->data, bits->len);
965                                         }
966                                         p += 1 + bits->len;
967                                 }
968                         }
969                 }
970                 else
971                         err = ASN_EINVAL;
972                 break;
973
974         case OCTET_STRING:
975         case ObjectDescriptor:
976         case EXTERNAL:
977         case REAL:
978         case EMBEDDED_PDV:
979                 bb = nil;
980                 switch(e.val.tag) {
981                 case VOctets:
982                         bb = e.val.u.octetsval;
983                         break;
984                 case VReal:
985                         bb = e.val.u.realval;
986                         break;
987                 case VOther:
988                         bb = e.val.u.otherval;
989                         break;
990                 }
991                 if(bb != nil) {
992                         if(!lenonly)
993                                 memmove(p, bb->data, bb->len);
994                         p += bb->len;
995                 }
996                 else
997                         err = ASN_EINVAL;
998                 break;
999
1000         case NULLTAG:
1001                 break;
1002
1003         case OBJECT_ID:
1004                 if(is_oid(&e, &oid)) {
1005                         for(k = 0; k < oid->len; k++) {
1006                                 v = oid->data[k];
1007                                 if(k == 0) {
1008                                         v *= 40;
1009                                         if(oid->len > 1)
1010                                                 v += oid->data[++k];
1011                                 }
1012                                 uint7_enc(&p, v, lenonly);
1013                         }
1014                 }
1015                 else
1016                         err = ASN_EINVAL;
1017                 break;
1018
1019         case SEQUENCE:
1020         case SETOF:
1021                 el = nil;
1022                 if(e.val.tag == VSeq)
1023                         el = e.val.u.seqval;
1024                 else if(e.val.tag == VSet)
1025                         el = e.val.u.setval;
1026                 else
1027                         err = ASN_EINVAL;
1028                 if(el != nil) {
1029                         *pconstr = CONSTR_MASK;
1030                         for(; el != nil; el = el->tl) {
1031                                 err = enc(&p, el->hd, lenonly);
1032                                 if(err != ASN_OK)
1033                                         break;
1034                         }
1035                 }
1036                 break;
1037
1038         case UTF8String:
1039         case NumericString:
1040         case PrintableString:
1041         case TeletexString:
1042         case VideotexString:
1043         case IA5String:
1044         case UTCTime:
1045         case GeneralizedTime:
1046         case GraphicString:
1047         case VisibleString:
1048         case GeneralString:
1049         case UniversalString:
1050         case BMPString:
1051                 if(e.val.tag == VString) {
1052                         s = e.val.u.stringval;
1053                         if(s != nil) {
1054                                 v = strlen(s);
1055                                 if(!lenonly)
1056                                         memmove(p, s, v);
1057                                 p += v;
1058                         }
1059                 }
1060                 else
1061                         err = ASN_EINVAL;
1062                 break;
1063
1064         default:
1065                 err = ASN_EINVAL;
1066         }
1067         *pp = p;
1068         return err;
1069 }
1070
1071 /*
1072  * Encode num as unsigned 7 bit values with top bit 1 on all bytes
1073  * except last, only putting in bytes if !lenonly.
1074  */
1075 static void
1076 uint7_enc(uchar** pp, int num, int lenonly)
1077 {
1078         int n;
1079         int v;
1080         int k;
1081         uchar* p;
1082
1083         p = *pp;
1084         n = 1;
1085         v = num >> 7;
1086         while(v > 0) {
1087                 v >>= 7;
1088                 n++;
1089         }
1090         if(lenonly)
1091                 p += n;
1092         else {
1093                 for(k = (n - 1)*7; k > 0; k -= 7)
1094                         *p++= ((num >> k)|0x80);
1095                 *p++ = (num&0x7F);
1096         }
1097         *pp = p;
1098 }
1099
1100 /*
1101  * Encode num as unsigned or signed integer,
1102  * only putting in bytes if !lenonly.
1103  * Encoding is length followed by bytes to concatenate.
1104  */
1105 static void
1106 int_enc(uchar** pp, int num, int unsgned, int lenonly)
1107 {
1108         int v;
1109         int n;
1110         int prevv;
1111         int k;
1112         uchar* p;
1113
1114         p = *pp;
1115         v = num;
1116         if(v < 0)
1117                 v = -(v + 1);
1118         n = 1;
1119         prevv = v;
1120         v >>= 8;
1121         while(v > 0) {
1122                 prevv = v;
1123                 v >>= 8;
1124                 n++;
1125         }
1126         if(!unsgned && (prevv&0x80))
1127                 n++;
1128         if(lenonly)
1129                 p += n;
1130         else {
1131                 for(k = (n - 1)*8; k >= 0; k -= 8)
1132                         *p++ = (num >> k);
1133         }
1134         *pp = p;
1135 }
1136
1137 static int
1138 ints_eq(Ints* a, Ints* b)
1139 {
1140         int     alen;
1141         int     i;
1142
1143         alen = a->len;
1144         if(alen != b->len)
1145                 return 0;
1146         for(i = 0; i < alen; i++)
1147                 if(a->data[i] != b->data[i])
1148                         return 0;
1149         return 1;
1150 }
1151
1152 /*
1153  * Look up o in tab (which must have nil entry to terminate).
1154  * Return index of matching entry, or -1 if none.
1155  */
1156 static int
1157 oid_lookup(Ints* o, Ints** tab)
1158 {
1159         int i;
1160
1161         for(i = 0; tab[i] != nil; i++)
1162                 if(ints_eq(o, tab[i]))
1163                         return  i;
1164         return -1;
1165 }
1166
1167 /*
1168  * Return true if *pe is a SEQUENCE, and set *pseq to
1169  * the value of the sequence if so.
1170  */
1171 static int
1172 is_seq(Elem* pe, Elist** pseq)
1173 {
1174         if(pe->tag.class == Universal && pe->tag.num == SEQUENCE && pe->val.tag == VSeq) {
1175                 *pseq = pe->val.u.seqval;
1176                 return 1;
1177         }
1178         return 0;
1179 }
1180
1181 static int
1182 is_set(Elem* pe, Elist** pset)
1183 {
1184         if(pe->tag.class == Universal && pe->tag.num == SETOF && pe->val.tag == VSet) {
1185                 *pset = pe->val.u.setval;
1186                 return 1;
1187         }
1188         return 0;
1189 }
1190
1191 static int
1192 is_int(Elem* pe, int* pint)
1193 {
1194         if(pe->tag.class == Universal) {
1195                 if(pe->tag.num == INTEGER && pe->val.tag == VInt) {
1196                         *pint = pe->val.u.intval;
1197                         return 1;
1198                 }
1199                 else if(pe->tag.num == BOOLEAN && pe->val.tag == VBool) {
1200                         *pint = pe->val.u.boolval;
1201                         return 1;
1202                 }
1203         }
1204         return 0;
1205 }
1206
1207 /*
1208  * for convience, all VInt's are readable via this routine,
1209  * as well as all VBigInt's
1210  */
1211 static int
1212 is_bigint(Elem* pe, Bytes** pbigint)
1213 {
1214         if(pe->tag.class == Universal && pe->tag.num == INTEGER && pe->val.tag == VBigInt) {
1215                 *pbigint = pe->val.u.bigintval;
1216                 return 1;
1217         }
1218         return 0;
1219 }
1220
1221 static int
1222 is_bitstring(Elem* pe, Bits** pbits)
1223 {
1224         if(pe->tag.class == Universal && pe->tag.num == BIT_STRING && pe->val.tag == VBitString) {
1225                 *pbits = pe->val.u.bitstringval;
1226                 return 1;
1227         }
1228         return 0;
1229 }
1230
1231 static int
1232 is_octetstring(Elem* pe, Bytes** poctets)
1233 {
1234         if(pe->tag.class == Universal && pe->tag.num == OCTET_STRING && pe->val.tag == VOctets) {
1235                 *poctets = pe->val.u.octetsval;
1236                 return 1;
1237         }
1238         return 0;
1239 }
1240
1241 static int
1242 is_oid(Elem* pe, Ints** poid)
1243 {
1244         if(pe->tag.class == Universal && pe->tag.num == OBJECT_ID && pe->val.tag == VObjId) {
1245                 *poid = pe->val.u.objidval;
1246                 return 1;
1247         }
1248         return 0;
1249 }
1250
1251 static int
1252 is_string(Elem* pe, char** pstring)
1253 {
1254         if(pe->tag.class == Universal) {
1255                 switch(pe->tag.num) {
1256                 case UTF8String:
1257                 case NumericString:
1258                 case PrintableString:
1259                 case TeletexString:
1260                 case VideotexString:
1261                 case IA5String:
1262                 case GraphicString:
1263                 case VisibleString:
1264                 case GeneralString:
1265                 case UniversalString:
1266                 case BMPString:
1267                         if(pe->val.tag == VString) {
1268                                 *pstring = pe->val.u.stringval;
1269                                 return 1;
1270                         }
1271                 }
1272         }
1273         return 0;
1274 }
1275
1276 static int
1277 is_time(Elem* pe, char** ptime)
1278 {
1279         if(pe->tag.class == Universal
1280            && (pe->tag.num == UTCTime || pe->tag.num == GeneralizedTime)
1281            && pe->val.tag == VString) {
1282                 *ptime = pe->val.u.stringval;
1283                 return 1;
1284         }
1285         return 0;
1286 }
1287
1288
1289 /*
1290  * malloc and return a new Bytes structure capable of
1291  * holding len bytes. (len >= 0)
1292  */
1293 static Bytes*
1294 newbytes(int len)
1295 {
1296         Bytes* ans;
1297
1298         if(len < 0)
1299                 abort();
1300         ans = emalloc(sizeof(Bytes) + len);
1301         ans->len = len;
1302         return ans;
1303 }
1304
1305 /*
1306  * newbytes(len), with data initialized from buf
1307  */
1308 static Bytes*
1309 makebytes(uchar* buf, int len)
1310 {
1311         Bytes* ans;
1312
1313         ans = newbytes(len);
1314         memmove(ans->data, buf, len);
1315         return ans;
1316 }
1317
1318 static void
1319 freebytes(Bytes* b)
1320 {
1321         free(b);
1322 }
1323
1324 /*
1325  * Make a new Bytes, containing bytes of b1 followed by those of b2.
1326  * Either b1 or b2 or both can be nil.
1327  */
1328 static Bytes*
1329 catbytes(Bytes* b1, Bytes* b2)
1330 {
1331         Bytes* ans;
1332         int n;
1333
1334         if(b1 == nil) {
1335                 if(b2 == nil)
1336                         ans = newbytes(0);
1337                 else
1338                         ans = makebytes(b2->data, b2->len);
1339         }
1340         else if(b2 == nil) {
1341                 ans = makebytes(b1->data, b1->len);
1342         }
1343         else {
1344                 n = b1->len + b2->len;
1345                 ans = newbytes(n);
1346                 ans->len = n;
1347                 memmove(ans->data, b1->data, b1->len);
1348                 memmove(ans->data+b1->len, b2->data, b2->len);
1349         }
1350         return ans;
1351 }
1352
1353 /* len is number of ints */
1354 static Ints*
1355 newints(int len)
1356 {
1357         Ints* ans;
1358
1359         if(len < 0 || len > ((uint)-1>>1)/sizeof(int))
1360                 abort();
1361         ans = emalloc(sizeof(Ints) + len*sizeof(int));
1362         ans->len = len;
1363         return ans;
1364 }
1365
1366 static Ints*
1367 makeints(int* buf, int len)
1368 {
1369         Ints* ans;
1370
1371         ans = newints(len);
1372         memmove(ans->data, buf, len*sizeof(int));
1373         return ans;
1374 }
1375
1376 static void
1377 freeints(Ints* b)
1378 {
1379         free(b);
1380 }
1381
1382 /* len is number of bytes */
1383 static Bits*
1384 newbits(int len)
1385 {
1386         Bits* ans;
1387
1388         if(len < 0)
1389                 abort();
1390         ans = emalloc(sizeof(Bits) + len);
1391         ans->len = len;
1392         ans->unusedbits = 0;
1393         return ans;
1394 }
1395
1396 static Bits*
1397 makebits(uchar* buf, int len, int unusedbits)
1398 {
1399         Bits* ans;
1400
1401         ans = newbits(len);
1402         memmove(ans->data, buf, len);
1403         ans->unusedbits = unusedbits;
1404         return ans;
1405 }
1406
1407 static void
1408 freebits(Bits* b)
1409 {
1410         free(b);
1411 }
1412
1413 static Elist*
1414 mkel(Elem e, Elist* tail)
1415 {
1416         Elist* el;
1417
1418         el = (Elist*)emalloc(sizeof(Elist));
1419         setmalloctag(el, getcallerpc(&e));
1420         el->hd = e;
1421         el->tl = tail;
1422         return el;
1423 }
1424
1425 static int
1426 elistlen(Elist* el)
1427 {
1428         int ans = 0;
1429         while(el != nil) {
1430                 ans++;
1431                 el = el->tl;
1432         }
1433         return ans;
1434 }
1435
1436 /* Frees elist, but not fields inside values of constituent elems */
1437 static void
1438 freeelist(Elist* el)
1439 {
1440         Elist* next;
1441
1442         while(el != nil) {
1443                 next = el->tl;
1444                 free(el);
1445                 el = next;
1446         }
1447 }
1448
1449 /* free any allocated structures inside v (recursively freeing Elists) */
1450 static void
1451 freevalfields(Value* v)
1452 {
1453         Elist* el;
1454         Elist* l;
1455         if(v == nil)
1456                 return;
1457         switch(v->tag) {
1458         case VOctets:
1459                 freebytes(v->u.octetsval);
1460                 break;
1461         case VBigInt:
1462                 freebytes(v->u.bigintval);
1463                 break;
1464         case VReal:
1465                 freebytes(v->u.realval);
1466                 break;
1467         case VOther:
1468                 freebytes(v->u.otherval);
1469                 break;
1470         case VBitString:
1471                 freebits(v->u.bitstringval);
1472                 break;
1473         case VObjId:
1474                 freeints(v->u.objidval);
1475                 break;
1476         case VString:
1477                 free(v->u.stringval);
1478                 break;
1479         case VSeq:
1480                 el = v->u.seqval;
1481                 for(l = el; l != nil; l = l->tl)
1482                         freevalfields(&l->hd.val);
1483                 freeelist(el);
1484                 break;
1485         case VSet:
1486                 el = v->u.setval;
1487                 for(l = el; l != nil; l = l->tl)
1488                         freevalfields(&l->hd.val);
1489                 freeelist(el);
1490                 break;
1491         }
1492         memset(v, 0, sizeof(*v));
1493 }
1494
1495 static mpint*
1496 asn1mpint(Elem *e)
1497 {
1498         Bytes *b;
1499         int v;
1500
1501         if(is_int(e, &v))
1502                 return itomp(v, nil);
1503         if(is_bigint(e, &b))
1504                 return betomp(b->data, b->len, nil);
1505         return nil;
1506 }
1507
1508 /* end of general ASN1 functions */
1509
1510
1511
1512
1513
1514 /*=============================================================*/
1515 /*
1516  * Decode and parse an X.509 Certificate, defined by this ASN1:
1517  *      Certificate ::= SEQUENCE {
1518  *              certificateInfo CertificateInfo,
1519  *              signatureAlgorithm AlgorithmIdentifier,
1520  *              signature BIT STRING }
1521  *
1522  *      CertificateInfo ::= SEQUENCE {
1523  *              version [0] INTEGER DEFAULT v1 (0),
1524  *              serialNumber INTEGER,
1525  *              signature AlgorithmIdentifier,
1526  *              issuer Name,
1527  *              validity Validity,
1528  *              subject Name,
1529  *              subjectPublicKeyInfo SubjectPublicKeyInfo }
1530  *      (version v2 has two more fields, optional unique identifiers for
1531  *  issuer and subject; since we ignore these anyway, we won't parse them)
1532  *
1533  *      Validity ::= SEQUENCE {
1534  *              notBefore UTCTime,
1535  *              notAfter UTCTime }
1536  *
1537  *      SubjectPublicKeyInfo ::= SEQUENCE {
1538  *              algorithm AlgorithmIdentifier,
1539  *              subjectPublicKey BIT STRING }
1540  *
1541  *      AlgorithmIdentifier ::= SEQUENCE {
1542  *              algorithm OBJECT IDENTIFER,
1543  *              parameters ANY DEFINED BY ALGORITHM OPTIONAL }
1544  *
1545  *      Name ::= SEQUENCE OF RelativeDistinguishedName
1546  *
1547  *      RelativeDistinguishedName ::= SETOF SIZE(1..MAX) OF AttributeTypeAndValue
1548  *
1549  *      AttributeTypeAndValue ::= SEQUENCE {
1550  *              type OBJECT IDENTIFER,
1551  *              value DirectoryString }
1552  *      (selected attributes have these Object Ids:
1553  *              commonName {2 5 4 3}
1554  *              countryName {2 5 4 6}
1555  *              localityName {2 5 4 7}
1556  *              stateOrProvinceName {2 5 4 8}
1557  *              organizationName {2 5 4 10}
1558  *              organizationalUnitName {2 5 4 11}
1559  *      )
1560  *
1561  *      DirectoryString ::= CHOICE {
1562  *              teletexString TeletexString,
1563  *              printableString PrintableString,
1564  *              universalString UniversalString }
1565  *
1566  *  See rfc1423, rfc2437 for AlgorithmIdentifier, subjectPublicKeyInfo, signature.
1567  *
1568  *  Not yet implemented:
1569  *   CertificateRevocationList ::= SIGNED SEQUENCE{
1570  *           signature       AlgorithmIdentifier,
1571  *           issuer          Name,
1572  *           lastUpdate      UTCTime,
1573  *           nextUpdate      UTCTime,
1574  *           revokedCertificates
1575  *                           SEQUENCE OF CRLEntry OPTIONAL}
1576  *   CRLEntry ::= SEQUENCE{
1577  *           userCertificate SerialNumber,
1578  *           revocationDate UTCTime}
1579  */
1580
1581 typedef struct CertX509 {
1582         int     serial;
1583         char*   issuer;
1584         char*   validity_start;
1585         char*   validity_end;
1586         char*   subject;
1587         int     publickey_alg;
1588         Bits*   publickey;
1589         int     signature_alg;
1590         Bits*   signature;
1591         int     curve;
1592 } CertX509;
1593
1594 /* Algorithm object-ids */
1595 enum {
1596         ALG_rsaEncryption,
1597         ALG_md2WithRSAEncryption,
1598         ALG_md4WithRSAEncryption,
1599         ALG_md5WithRSAEncryption,
1600
1601         ALG_sha1WithRSAEncryption,
1602         ALG_sha1WithRSAEncryptionOiw,
1603
1604         ALG_sha256WithRSAEncryption,
1605         ALG_sha384WithRSAEncryption,
1606         ALG_sha512WithRSAEncryption,
1607         ALG_sha224WithRSAEncryption,
1608
1609         ALG_ecPublicKey,
1610         ALG_sha1WithECDSA,
1611         ALG_sha256WithECDSA,
1612         ALG_sha384WithECDSA,
1613         ALG_sha512WithECDSA,
1614
1615         ALG_md5,
1616         ALG_sha1,
1617         ALG_sha256,
1618         ALG_sha384,
1619         ALG_sha512,
1620         ALG_sha224,
1621
1622         NUMALGS
1623 };
1624
1625 typedef struct Ints15 {
1626         int             len;
1627         int             data[15];
1628 } Ints15;
1629
1630 typedef struct DigestAlg {
1631         int             alg;
1632         DigestState*    (*fun)(uchar*,ulong,uchar*,DigestState*);
1633         int             len;
1634 } DigestAlg;
1635
1636 static DigestAlg alg_md5 = { ALG_md5, md5, MD5dlen};
1637 static DigestAlg alg_sha1 = { ALG_sha1, sha1, SHA1dlen };
1638 static DigestAlg alg_sha256 = { ALG_sha256, sha2_256, SHA2_256dlen };
1639 static DigestAlg alg_sha384 = { ALG_sha384, sha2_384, SHA2_384dlen };
1640 static DigestAlg alg_sha512 = { ALG_sha512, sha2_512, SHA2_512dlen };
1641 static DigestAlg alg_sha224 = { ALG_sha224, sha2_224, SHA2_224dlen };
1642
1643 /* maximum length of digest output of the digest algs above */
1644 enum {
1645         MAXdlen = SHA2_512dlen,
1646 };
1647
1648 static Ints15 oid_rsaEncryption = {7, 1, 2, 840, 113549, 1, 1, 1 };
1649
1650 static Ints15 oid_md2WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 2 };
1651 static Ints15 oid_md4WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 3 };
1652 static Ints15 oid_md5WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 4 };
1653 static Ints15 oid_sha1WithRSAEncryption ={7, 1, 2, 840, 113549, 1, 1, 5 };
1654 static Ints15 oid_sha1WithRSAEncryptionOiw ={6, 1, 3, 14, 3, 2, 29 };
1655 static Ints15 oid_sha256WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 11 };
1656 static Ints15 oid_sha384WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 12 };
1657 static Ints15 oid_sha512WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 13 };
1658 static Ints15 oid_sha224WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 14 };
1659
1660 static Ints15 oid_ecPublicKey = {6, 1, 2, 840, 10045, 2, 1 };
1661 static Ints15 oid_sha1WithECDSA = {6, 1, 2, 840, 10045, 4, 1 };
1662 static Ints15 oid_sha256WithECDSA = {7, 1, 2, 840, 10045, 4, 3, 2 };
1663 static Ints15 oid_sha384WithECDSA = {7, 1, 2, 840, 10045, 4, 3, 3 };
1664 static Ints15 oid_sha512WithECDSA = {7, 1, 2, 840, 10045, 4, 3, 4 };
1665
1666 static Ints15 oid_md5 = {6, 1, 2, 840, 113549, 2, 5 };
1667 static Ints15 oid_sha1 = {6, 1, 3, 14, 3, 2, 26 };
1668 static Ints15 oid_sha256= {9, 2, 16, 840, 1, 101, 3, 4, 2, 1 };
1669 static Ints15 oid_sha384= {9, 2, 16, 840, 1, 101, 3, 4, 2, 2 };
1670 static Ints15 oid_sha512= {9, 2, 16, 840, 1, 101, 3, 4, 2, 3 };
1671 static Ints15 oid_sha224= {9, 2, 16, 840, 1, 101, 3, 4, 2, 4 };
1672
1673 static Ints *alg_oid_tab[NUMALGS+1] = {
1674         (Ints*)&oid_rsaEncryption,
1675         (Ints*)&oid_md2WithRSAEncryption,
1676         (Ints*)&oid_md4WithRSAEncryption,
1677         (Ints*)&oid_md5WithRSAEncryption,
1678
1679         (Ints*)&oid_sha1WithRSAEncryption,
1680         (Ints*)&oid_sha1WithRSAEncryptionOiw,
1681
1682         (Ints*)&oid_sha256WithRSAEncryption,
1683         (Ints*)&oid_sha384WithRSAEncryption,
1684         (Ints*)&oid_sha512WithRSAEncryption,
1685         (Ints*)&oid_sha224WithRSAEncryption,
1686
1687         (Ints*)&oid_ecPublicKey,
1688         (Ints*)&oid_sha1WithECDSA,
1689         (Ints*)&oid_sha256WithECDSA,
1690         (Ints*)&oid_sha384WithECDSA,
1691         (Ints*)&oid_sha512WithECDSA,
1692
1693         (Ints*)&oid_md5,
1694         (Ints*)&oid_sha1,
1695         (Ints*)&oid_sha256,
1696         (Ints*)&oid_sha384,
1697         (Ints*)&oid_sha512,
1698         (Ints*)&oid_sha224,
1699         nil
1700 };
1701
1702 static DigestAlg *digestalg[NUMALGS+1] = {
1703         &alg_md5, &alg_md5, &alg_md5, &alg_md5,
1704         &alg_sha1, &alg_sha1,
1705         &alg_sha256, &alg_sha384, &alg_sha512, &alg_sha224,
1706         &alg_sha256, &alg_sha1, &alg_sha256, &alg_sha384, &alg_sha512,
1707         &alg_md5, &alg_sha1, &alg_sha256, &alg_sha384, &alg_sha512, &alg_sha224,
1708         nil
1709 };
1710
1711 static Bytes* encode_digest(DigestAlg *da, uchar *digest);
1712
1713 static Ints15 oid_secp256r1 = {7, 1, 2, 840, 10045, 3, 1, 7};
1714 static Ints15 oid_secp384r1 = {5, 1, 3, 132, 0, 34};
1715
1716 static Ints *namedcurves_oid_tab[] = {
1717         (Ints*)&oid_secp256r1,
1718         (Ints*)&oid_secp384r1,
1719         nil,
1720 };
1721 static void (*namedcurves[])(mpint *p, mpint *a, mpint *b, mpint *x, mpint *y, mpint *n, mpint *h) = {
1722         secp256r1,
1723         secp384r1,
1724         nil,
1725 };
1726
1727 static void
1728 freecert(CertX509* c)
1729 {
1730         if(c == nil)
1731                 return;
1732         free(c->issuer);
1733         free(c->validity_start);
1734         free(c->validity_end);
1735         free(c->subject);
1736         freebits(c->publickey);
1737         freebits(c->signature);
1738         free(c);
1739 }
1740
1741 /*
1742  * Parse the Name ASN1 type.
1743  * The sequence of RelativeDistinguishedName's gives a sort of pathname,
1744  * from most general to most specific.  Each element of the path can be
1745  * one or more (but usually just one) attribute-value pair, such as
1746  * countryName="US".
1747  * We'll just form a "postal-style" address string by concatenating the elements
1748  * from most specific to least specific, separated by commas.
1749  * Return name-as-string (which must be freed by caller).
1750  */
1751 static char*
1752 parse_name(Elem* e)
1753 {
1754         Elist* el;
1755         Elem* es;
1756         Elist* esetl;
1757         Elem* eat;
1758         Elist* eatl;
1759         char* s;
1760         enum { MAXPARTS = 100 };
1761         char* parts[MAXPARTS];
1762         int i;
1763         int plen;
1764         char* ans = nil;
1765
1766         if(!is_seq(e, &el))
1767                 goto errret;
1768         i = 0;
1769         plen = 0;
1770         while(el != nil) {
1771                 es = &el->hd;
1772                 if(!is_set(es, &esetl))
1773                         goto errret;
1774                 while(esetl != nil) {
1775                         eat = &esetl->hd;
1776                         if(!is_seq(eat, &eatl) || elistlen(eatl) != 2)
1777                                 goto errret;
1778                         if(!is_string(&eatl->tl->hd, &s) || i>=MAXPARTS)
1779                                 goto errret;
1780                         parts[i++] = s;
1781                         plen += strlen(s) + 2;          /* room for ", " after */
1782                         esetl = esetl->tl;
1783                 }
1784                 el = el->tl;
1785         }
1786         if(i > 0) {
1787                 ans = (char*)emalloc(plen);
1788                 *ans = '\0';
1789                 while(--i >= 0) {
1790                         s = parts[i];
1791                         strcat(ans, s);
1792                         if(i > 0)
1793                                 strcat(ans, ", ");
1794                 }
1795         }
1796
1797 errret:
1798         return ans;
1799 }
1800
1801 /*
1802  * Parse an AlgorithmIdentifer ASN1 type.
1803  * Look up the oid in oid_tab and return one of OID_rsaEncryption, etc..,
1804  * or -1 if not found.
1805  * For now, ignore parameters, since none of our algorithms need them.
1806  */
1807 static int
1808 parse_alg(Elem* e)
1809 {
1810         Elist* el;
1811         Ints* oid;
1812
1813         if(!is_seq(e, &el) || el == nil || !is_oid(&el->hd, &oid))
1814                 return -1;
1815         return oid_lookup(oid, alg_oid_tab);
1816 }
1817
1818 static int
1819 parse_curve(Elem* e)
1820 {
1821         Elist* el;
1822         Ints* oid;
1823
1824         if(!is_seq(e, &el) || elistlen(el)<2 || !is_oid(&el->tl->hd, &oid))
1825                 return -1;
1826         return oid_lookup(oid, namedcurves_oid_tab);
1827 }
1828
1829 static CertX509*
1830 decode_cert(uchar *buf, int len)
1831 {
1832         int ok = 0;
1833         int n;
1834         Elem  ecert;
1835         Elem* ecertinfo;
1836         Elem* esigalg;
1837         Elem* esig;
1838         Elem* eserial;
1839         Elem* eissuer;
1840         Elem* evalidity;
1841         Elem* esubj;
1842         Elem* epubkey;
1843         Elist* el;
1844         Elist* elcert = nil;
1845         Elist* elcertinfo = nil;
1846         Elist* elvalidity = nil;
1847         Elist* elpubkey = nil;
1848         Bits* bits = nil;
1849         Bytes* b;
1850         Elem* e;
1851         CertX509* c = nil;
1852
1853         if(decode(buf, len, &ecert) != ASN_OK)
1854                 goto errret;
1855
1856         c = (CertX509*)emalloc(sizeof(CertX509));
1857         c->serial = -1;
1858         c->issuer = nil;
1859         c->validity_start = nil;
1860         c->validity_end = nil;
1861         c->subject = nil;
1862         c->publickey_alg = -1;
1863         c->publickey = nil;
1864         c->signature_alg = -1;
1865         c->signature = nil;
1866
1867         /* Certificate */
1868         if(!is_seq(&ecert, &elcert) || elistlen(elcert) !=3)
1869                 goto errret;
1870         ecertinfo = &elcert->hd;
1871         el = elcert->tl;
1872         esigalg = &el->hd;
1873         c->signature_alg = parse_alg(esigalg);
1874         el = el->tl;
1875         esig = &el->hd;
1876
1877         /* Certificate Info */
1878         if(!is_seq(ecertinfo, &elcertinfo))
1879                 goto errret;
1880         n = elistlen(elcertinfo);
1881         if(n < 6)
1882                 goto errret;
1883         eserial =&elcertinfo->hd;
1884         el = elcertinfo->tl;
1885         /* check for optional version, marked by explicit context tag 0 */
1886         if(eserial->tag.class == Context && eserial->tag.num == 0) {
1887                 eserial = &el->hd;
1888                 if(n < 7)
1889                         goto errret;
1890                 el = el->tl;
1891         }
1892
1893         if(parse_alg(&el->hd) != c->signature_alg)
1894                 goto errret;
1895         el = el->tl;
1896         eissuer = &el->hd;
1897         el = el->tl;
1898         evalidity = &el->hd;
1899         el = el->tl;
1900         esubj = &el->hd;
1901         el = el->tl;
1902         epubkey = &el->hd;
1903         if(!is_int(eserial, &c->serial)) {
1904                 if(!is_bigint(eserial, &b))
1905                         goto errret;
1906                 c->serial = -1; /* else we have to change cert struct */
1907         }
1908         c->issuer = parse_name(eissuer);
1909         if(c->issuer == nil)
1910                 goto errret;
1911         /* Validity */
1912         if(!is_seq(evalidity, &elvalidity))
1913                 goto errret;
1914         if(elistlen(elvalidity) != 2)
1915                 goto errret;
1916         e = &elvalidity->hd;
1917         if(!is_time(e, &c->validity_start))
1918                 goto errret;
1919         e->val.u.stringval = nil;       /* string ownership transfer */
1920         e = &elvalidity->tl->hd;
1921         if(!is_time(e, &c->validity_end))
1922                 goto errret;
1923         e->val.u.stringval = nil;       /* string ownership transfer */
1924
1925         /* resume CertificateInfo */
1926         c->subject = parse_name(esubj);
1927         if(c->subject == nil)
1928                 goto errret;
1929
1930         /* SubjectPublicKeyInfo */
1931         if(!is_seq(epubkey, &elpubkey))
1932                 goto errret;
1933         if(elistlen(elpubkey) != 2)
1934                 goto errret;
1935
1936         c->publickey_alg = parse_alg(&elpubkey->hd);
1937         if(c->publickey_alg < 0)
1938                 goto errret;
1939         c->curve = -1;
1940         if(c->publickey_alg == ALG_ecPublicKey){
1941                 c->curve = parse_curve(&elpubkey->hd);
1942                 if(c->curve < 0)
1943                         goto errret;
1944         }
1945         elpubkey = elpubkey->tl;
1946         if(!is_bitstring(&elpubkey->hd, &bits))
1947                 goto errret;
1948         elpubkey->hd.val.u.bitstringval = nil;  /* transfer ownership */
1949         c->publickey = bits;
1950
1951         /*resume Certificate */
1952         if(c->signature_alg < 0)
1953                 goto errret;
1954         if(!is_bitstring(esig, &bits))
1955                 goto errret;
1956         esig->val.u.bitstringval = nil; /* transfer ownership */
1957         c->signature = bits;
1958         ok = 1;
1959
1960 errret:
1961         freevalfields(&ecert.val);      /* recurses through lists, too */
1962         if(!ok){
1963                 freecert(c);
1964                 c = nil;
1965         }
1966         return c;
1967 }
1968
1969 /*
1970  *      RSAPublickKey ::= SEQUENCE {
1971  *              modulus INTEGER,
1972  *              publicExponent INTEGER
1973  *      }
1974  */
1975 RSApub*
1976 asn1toRSApub(uchar *buf, int len)
1977 {
1978         Elem e;
1979         Elist *el;
1980         RSApub* key;
1981
1982         key = nil;
1983         if(decode(buf, len, &e) != ASN_OK)
1984                 goto errret;
1985         if(!is_seq(&e, &el) || elistlen(el) != 2)
1986                 goto errret;
1987
1988         key = rsapuballoc();
1989         if((key->n = asn1mpint(&el->hd)) == nil)
1990                 goto errret;
1991         el = el->tl;
1992         if((key->ek = asn1mpint(&el->hd)) == nil)
1993                 goto errret;
1994
1995         freevalfields(&e.val);
1996         return key;
1997 errret:
1998         freevalfields(&e.val);
1999         rsapubfree(key);
2000         return nil;
2001
2002 }
2003
2004 /*
2005  *      RSAPrivateKey ::= SEQUENCE {
2006  *              version Version,
2007  *              modulus INTEGER, -- n
2008  *              publicExponent INTEGER, -- e
2009  *              privateExponent INTEGER, -- d
2010  *              prime1 INTEGER, -- p
2011  *              prime2 INTEGER, -- q
2012  *              exponent1 INTEGER, -- d mod (p-1)
2013  *              exponent2 INTEGER, -- d mod (q-1)
2014  *              coefficient INTEGER -- (inverse of q) mod p }
2015  */
2016 RSApriv*
2017 asn1toRSApriv(uchar *buf, int len)
2018 {
2019         int version;
2020         Elem e;
2021         Elist *el;
2022         Bytes *b;
2023         RSApriv* key = nil;
2024
2025         if(decode(buf, len, &e) != ASN_OK)
2026                 goto errret;
2027         if(!is_seq(&e, &el))
2028                 goto errret;
2029
2030         if(!is_int(&el->hd, &version) || version != 0)
2031                 goto errret;
2032
2033         if(elistlen(el) != 9){
2034                 if(elistlen(el) == 3
2035                 && parse_alg(&el->tl->hd) == ALG_rsaEncryption
2036                 && is_octetstring(&el->tl->tl->hd, &b)){
2037                         key = asn1toRSApriv(b->data, b->len);
2038                         if(key != nil)
2039                                 goto done;
2040                 }
2041                 goto errret;
2042         }
2043
2044         key = rsaprivalloc();
2045         el = el->tl;
2046         if((key->pub.n = asn1mpint(&el->hd)) == nil)
2047                 goto errret;
2048
2049         el = el->tl;
2050         if((key->pub.ek = asn1mpint(&el->hd)) == nil)
2051                 goto errret;
2052
2053         el = el->tl;
2054         if((key->dk = asn1mpint(&el->hd)) == nil)
2055                 goto errret;
2056
2057         el = el->tl;
2058         if((key->q = asn1mpint(&el->hd)) == nil)
2059                 goto errret;
2060
2061         el = el->tl;
2062         if((key->p = asn1mpint(&el->hd)) == nil)
2063                 goto errret;
2064
2065         el = el->tl;
2066         if((key->kq = asn1mpint(&el->hd)) == nil)
2067                 goto errret;
2068
2069         el = el->tl;
2070         if((key->kp = asn1mpint(&el->hd)) == nil)
2071                 goto errret;
2072
2073         el = el->tl;
2074         if((key->c2 = asn1mpint(&el->hd)) == nil)
2075                 goto errret;
2076
2077 done:
2078         freevalfields(&e.val);
2079         return key;
2080 errret:
2081         freevalfields(&e.val);
2082         rsaprivfree(key);
2083         return nil;
2084 }
2085
2086 /*
2087  *      DSAPrivateKey ::= SEQUENCE{
2088  *              version Version,
2089  *              p INTEGER,
2090  *              q INTEGER,
2091  *              g INTEGER, -- alpha
2092  *              pub_key INTEGER, -- key
2093  *              priv_key INTEGER, -- secret
2094  *      }
2095  */
2096 DSApriv*
2097 asn1toDSApriv(uchar *buf, int len)
2098 {
2099         int version;
2100         Elem e;
2101         Elist *el;
2102         DSApriv* key = nil;
2103
2104         if(decode(buf, len, &e) != ASN_OK)
2105                 goto errret;
2106         if(!is_seq(&e, &el) || elistlen(el) != 6)
2107                 goto errret;
2108         version = -1;
2109         if(!is_int(&el->hd, &version) || version != 0)
2110                 goto errret;
2111
2112         key = dsaprivalloc();
2113         el = el->tl;
2114         if((key->pub.p = asn1mpint(&el->hd)) == nil)
2115                 goto errret;
2116
2117         el = el->tl;
2118         if((key->pub.q = asn1mpint(&el->hd)) == nil)
2119                 goto errret;
2120
2121         el = el->tl;
2122         if((key->pub.alpha = asn1mpint(&el->hd)) == nil)
2123                 goto errret;
2124
2125         el = el->tl;
2126         if((key->pub.key = asn1mpint(&el->hd)) == nil)
2127                 goto errret;
2128
2129         el = el->tl;
2130         if((key->secret = asn1mpint(&el->hd)) == nil)
2131                 goto errret;
2132
2133         freevalfields(&e.val);
2134         return key;
2135 errret:
2136         freevalfields(&e.val);
2137         dsaprivfree(key);
2138         return nil;
2139 }
2140
2141 /*
2142  * digest(CertificateInfo)
2143  * Our ASN.1 library doesn't return pointers into the original
2144  * data array, so we need to do a little hand decoding.
2145  */
2146 static int
2147 digest_certinfo(uchar *cert, int ncert, DigestAlg *da, uchar *digest)
2148 {
2149         uchar *info, *p, *pend;
2150         int isconstr, length;
2151         Tag tag;
2152         Elem elem;
2153
2154         p = cert;
2155         pend = cert + ncert;
2156         if(tag_decode(&p, pend, &tag, &isconstr) != ASN_OK ||
2157            tag.class != Universal || tag.num != SEQUENCE ||
2158            length_decode(&p, pend, &length) != ASN_OK ||
2159            p+length > pend ||
2160            p+length < p)
2161                 return -1;
2162         info = p;
2163         if(ber_decode(&p, pend, &elem) != ASN_OK)
2164                 return -1;
2165         freevalfields(&elem.val);
2166         if(elem.tag.num != SEQUENCE)
2167                 return -1;
2168         (*da->fun)(info, p - info, digest, nil);
2169         return da->len;
2170 }
2171
2172 mpint*
2173 pkcs1padbuf(uchar *buf, int len, mpint *modulus, int blocktype)
2174 {
2175         int i, n = (mpsignif(modulus)-1)/8;
2176         int pad = n - 2 - len;
2177         uchar *p;
2178         mpint *mp;
2179
2180         if(pad < 8){
2181                 werrstr("rsa modulus too small");
2182                 return nil;
2183         }
2184         if((p = malloc(n)) == nil)
2185                 return nil;
2186         p[0] = blocktype;
2187         switch(blocktype){
2188         default:
2189         case 1:
2190                 memset(p+1, 0xFF, pad);
2191                 break;
2192         case 2:
2193                 for(i=1; i <= pad; i++)
2194                         p[i] = 1 + nfastrand(255);
2195                 break;
2196         }
2197         p[1+pad] = 0;
2198         memmove(p+2+pad, buf, len);
2199         mp = betomp(p, n, nil);
2200         free(p);
2201         return mp;
2202 }
2203
2204 int
2205 pkcs1unpadbuf(uchar *buf, int len, mpint *modulus, int blocktype)
2206 {
2207         uchar *p = buf + 1, *e = buf + len;
2208
2209         if(len < 1 || len != (mpsignif(modulus)-1)/8 || buf[0] != blocktype)
2210                 return -1;
2211         switch(blocktype){
2212         default:
2213         case 1:
2214                 while(p < e && *p == 0xFF)
2215                         p++;
2216                 break;
2217         case 2:
2218                 while(p < e && *p != 0x00)
2219                         p++;
2220                 break;
2221         }
2222         if(p - buf <= 8 || p >= e || *p++ != 0x00)
2223                 return -1;
2224         memmove(buf, p, len = e - p);
2225         return len;
2226 }
2227
2228 static char Ebadsig[] = "bad signature";
2229
2230 char*
2231 X509rsaverifydigest(uchar *sig, int siglen, uchar *edigest, int edigestlen, RSApub *pk)
2232 {
2233         mpint *x, *y;
2234         DigestAlg **dp;
2235         Bytes *digest;
2236         uchar *buf;
2237         int len;
2238         char *err;
2239
2240         x = betomp(sig, siglen, nil);
2241         y = rsaencrypt(pk, x, nil);
2242         mpfree(x);
2243         len = mptobe(y, nil, 0, &buf);
2244         mpfree(y);      
2245
2246         err = Ebadsig;
2247         len = pkcs1unpadbuf(buf, len, pk->n, 1);
2248         if(len == edigestlen && tsmemcmp(buf, edigest, edigestlen) == 0)
2249                 err = nil;
2250         for(dp = digestalg; err != nil && *dp != nil; dp++){
2251                 if((*dp)->len != edigestlen)
2252                         continue;
2253                 digest = encode_digest(*dp, edigest);
2254                 if(digest->len == len && tsmemcmp(digest->data, buf, len) == 0)
2255                         err = nil;
2256                 freebytes(digest);
2257         }
2258         free(buf);
2259         return err;
2260 }
2261
2262 char*
2263 X509ecdsaverifydigest(uchar *sig, int siglen, uchar *edigest, int edigestlen, ECdomain *dom, ECpub *pub)
2264 {
2265         Elem e;
2266         Elist *el;
2267         mpint *r, *s;
2268         char *err;
2269
2270         r = s = nil;
2271         err = Ebadsig;
2272         if(decode(sig, siglen, &e) != ASN_OK)
2273                 goto end;
2274         if(!is_seq(&e, &el) || elistlen(el) != 2)
2275                 goto end;
2276         r = asn1mpint(&el->hd);
2277         if(r == nil)
2278                 goto end;
2279         el = el->tl;
2280         s = asn1mpint(&el->hd);
2281         if(s == nil)
2282                 goto end;
2283         if(ecdsaverify(dom, pub, edigest, edigestlen, r, s))
2284                 err = nil;
2285 end:
2286         freevalfields(&e.val);
2287         mpfree(s);
2288         mpfree(r);
2289         return err;
2290 }
2291
2292 static void
2293 copysubject(char *name, int nname, char *subject)
2294 {
2295         char *e;
2296
2297         if(name == nil)
2298                 return;
2299         memset(name, 0, nname);
2300         if(subject == nil)
2301                 return;
2302         strncpy(name, subject, nname-1);
2303         e = strchr(name, ',');
2304         if(e != nil)
2305                 *e = 0; /* take just CN part of Distinguished Name */
2306 }
2307
2308 ECpub*
2309 X509toECpub(uchar *cert, int ncert, char *name, int nname, ECdomain *dom)
2310 {
2311         CertX509 *c;
2312         ECpub *pub;
2313
2314         c = decode_cert(cert, ncert);
2315         if(c == nil)
2316                 return nil;
2317         copysubject(name, nname, c->subject);
2318         pub = nil;
2319         if(c->publickey_alg == ALG_ecPublicKey){
2320                 ecdominit(dom, namedcurves[c->curve]);
2321                 pub = ecdecodepub(dom, c->publickey->data, c->publickey->len);
2322                 if(pub == nil)
2323                         ecdomfree(dom);
2324         }
2325         freecert(c);
2326         return pub;
2327 }
2328
2329 char*
2330 X509ecdsaverify(uchar *cert, int ncert, ECdomain *dom, ECpub *pk)
2331 {
2332         char *e;
2333         CertX509 *c;
2334         int digestlen;
2335         uchar digest[MAXdlen];
2336
2337         c = decode_cert(cert, ncert);
2338         if(c == nil)
2339                 return "cannot decode cert";
2340         digestlen = digest_certinfo(cert, ncert, digestalg[c->signature_alg], digest);
2341         if(digestlen <= 0){
2342                 freecert(c);
2343                 return "cannot decode certinfo";
2344         }
2345         e = X509ecdsaverifydigest(c->signature->data, c->signature->len, digest, digestlen, dom, pk);
2346         freecert(c);
2347         return e;
2348 }
2349
2350 RSApub*
2351 X509toRSApub(uchar *cert, int ncert, char *name, int nname)
2352 {
2353         CertX509 *c;
2354         RSApub *pub;
2355
2356         c = decode_cert(cert, ncert);
2357         if(c == nil)
2358                 return nil;
2359         copysubject(name, nname, c->subject);
2360         pub = nil;
2361         if(c->publickey_alg == ALG_rsaEncryption)
2362                 pub = asn1toRSApub(c->publickey->data, c->publickey->len);
2363         freecert(c);
2364         return pub;
2365 }
2366
2367 char*
2368 X509rsaverify(uchar *cert, int ncert, RSApub *pk)
2369 {
2370         char *e;
2371         CertX509 *c;
2372         int digestlen;
2373         uchar digest[MAXdlen];
2374
2375         c = decode_cert(cert, ncert);
2376         if(c == nil)
2377                 return "cannot decode cert";
2378         digestlen = digest_certinfo(cert, ncert, digestalg[c->signature_alg], digest);
2379         if(digestlen <= 0){
2380                 freecert(c);
2381                 return "cannot decode certinfo";
2382         }
2383         e = X509rsaverifydigest(c->signature->data, c->signature->len, digest, digestlen, pk);
2384         freecert(c);
2385         return e;
2386 }
2387
2388 /* ------- Elem constructors ---------- */
2389 static Elem
2390 Null(void)
2391 {
2392         Elem e;
2393
2394         e.tag.class = Universal;
2395         e.tag.num = NULLTAG;
2396         e.val.tag = VNull;
2397         return e;
2398 }
2399
2400 static Elem
2401 mkint(int j)
2402 {
2403         Elem e;
2404
2405         e.tag.class = Universal;
2406         e.tag.num = INTEGER;
2407         e.val.tag = VInt;
2408         e.val.u.intval = j;
2409         return e;
2410 }
2411
2412 static Elem
2413 mkbigint(mpint *p)
2414 {
2415         Elem e;
2416
2417         e.tag.class = Universal;
2418         e.tag.num = INTEGER;
2419         e.val.tag = VBigInt;
2420         e.val.u.bigintval = newbytes((mpsignif(p)+8)/8);
2421         if(p->sign < 0){
2422                 mpint *s = mpnew(e.val.u.bigintval->len*8+1);
2423                 mpleft(mpone, e.val.u.bigintval->len*8, s);
2424                 mpadd(p, s, s);
2425                 mptober(s, e.val.u.bigintval->data, e.val.u.bigintval->len);
2426                 mpfree(s);
2427         } else {
2428                 mptober(p, e.val.u.bigintval->data, e.val.u.bigintval->len);
2429         }
2430         return e;
2431 }
2432
2433 static int
2434 printable(char *s)
2435 {
2436         int c;
2437
2438         while((c = (uchar)*s++) != 0){
2439                 if((c >= 'a' && c <= 'z')
2440                 || (c >= 'A' && c <= 'Z')
2441                 || (c >= '0' && c <= '9')
2442                 || strchr("'=()+,-./:? ", c) != nil)
2443                         continue;
2444                 return 0;
2445         }
2446         return 1;
2447 }
2448
2449 #define DirectoryString 0
2450
2451 static Elem
2452 mkstring(char *s, int t)
2453 {
2454         Elem e;
2455
2456         if(t == DirectoryString)
2457                 t = printable(s) ? PrintableString : UTF8String;
2458         e.tag.class = Universal;
2459         e.tag.num = t;
2460         e.val.tag = VString;
2461         e.val.u.stringval = estrdup(s);
2462         return e;
2463 }
2464
2465 static Elem
2466 mkoctet(uchar *buf, int buflen)
2467 {
2468         Elem e;
2469
2470         e.tag.class = Universal;
2471         e.tag.num = OCTET_STRING;
2472         e.val.tag = VOctets;
2473         e.val.u.octetsval = makebytes(buf, buflen);
2474         return e;
2475 }
2476
2477 static Elem
2478 mkbits(uchar *buf, int buflen)
2479 {
2480         Elem e;
2481
2482         e.tag.class = Universal;
2483         e.tag.num = BIT_STRING;
2484         e.val.tag = VBitString;
2485         e.val.u.bitstringval = makebits(buf, buflen, 0);
2486         return e;
2487 }
2488
2489 static Elem
2490 mkutc(long t)
2491 {
2492         Elem e;
2493         char utc[50];
2494         Tm *tm = gmtime(t);
2495
2496         e.tag.class = Universal;
2497         e.tag.num = UTCTime;
2498         e.val.tag = VString;
2499         snprint(utc, sizeof(utc), "%.2d%.2d%.2d%.2d%.2d%.2dZ",
2500                 tm->year % 100, tm->mon+1, tm->mday, tm->hour, tm->min, tm->sec);
2501         e.val.u.stringval = estrdup(utc);
2502         return e;
2503 }
2504
2505 static Elem
2506 mkoid(Ints *oid)
2507 {
2508         Elem e;
2509
2510         e.tag.class = Universal;
2511         e.tag.num = OBJECT_ID;
2512         e.val.tag = VObjId;
2513         e.val.u.objidval = makeints(oid->data, oid->len);
2514         return e;
2515 }
2516
2517 static Elem
2518 mkseq(Elist *el)
2519 {
2520         Elem e;
2521
2522         e.tag.class = Universal;
2523         e.tag.num = SEQUENCE;
2524         e.val.tag = VSeq;
2525         e.val.u.seqval = el;
2526         return e;
2527 }
2528
2529 static Elem
2530 mkset(Elist *el)
2531 {
2532         Elem e;
2533
2534         e.tag.class = Universal;
2535         e.tag.num = SETOF;
2536         e.val.tag = VSet;
2537         e.val.u.setval = el;
2538         return e;
2539 }
2540
2541 static Elem
2542 mkalg(int alg)
2543 {
2544         return mkseq(mkel(mkoid(alg_oid_tab[alg]), mkel(Null(), nil)));
2545 }
2546
2547 typedef struct Ints7pref {
2548         int     len;
2549         int     data[7];
2550         char    prefix[4];
2551         int     stype;
2552 } Ints7pref;
2553 Ints7pref DN_oid[] = {
2554         {4, 2, 5, 4, 6, 0, 0, 0,        "C=", PrintableString},
2555         {4, 2, 5, 4, 8, 0, 0, 0,        "ST=",DirectoryString},
2556         {4, 2, 5, 4, 7, 0, 0, 0,        "L=", DirectoryString},
2557         {4, 2, 5, 4, 10, 0, 0, 0,       "O=", DirectoryString},
2558         {4, 2, 5, 4, 11, 0, 0, 0,       "OU=",DirectoryString},
2559         {4, 2, 5, 4, 3, 0, 0, 0,        "CN=",DirectoryString},
2560         {7, 1,2,840,113549,1,9,1,       "E=", IA5String},
2561         {7, 0,9,2342,19200300,100,1,25, "DC=",IA5String},
2562 };
2563
2564 static Elem
2565 mkname(Ints7pref *oid, char *subj)
2566 {
2567         return mkset(mkel(mkseq(mkel(mkoid((Ints*)oid), mkel(mkstring(subj, oid->stype), nil))), nil));
2568 }
2569
2570 static Elem
2571 mkDN(char *dn)
2572 {
2573         int i, j, nf;
2574         char *f[20], *prefix, *d2 = estrdup(dn);
2575         Elist* el = nil;
2576
2577         nf = tokenize(d2, f, nelem(f));
2578         for(i=nf-1; i>=0; i--){
2579                 for(j=0; j<nelem(DN_oid); j++){
2580                         prefix = DN_oid[j].prefix;
2581                         if(strncmp(f[i],prefix,strlen(prefix))==0){
2582                                 el = mkel(mkname(&DN_oid[j],f[i]+strlen(prefix)), el);
2583                                 break;
2584                         }
2585                 }
2586         }
2587         free(d2);
2588         return mkseq(el);
2589 }
2590
2591 /*
2592  * DigestInfo ::= SEQUENCE {
2593  *      digestAlgorithm AlgorithmIdentifier,
2594  *      digest OCTET STRING }
2595  */
2596 static Bytes*
2597 encode_digest(DigestAlg *da, uchar *digest)
2598 {
2599         Bytes *b = nil;
2600         Elem e = mkseq(
2601                 mkel(mkalg(da->alg),
2602                 mkel(mkoctet(digest, da->len),
2603                 nil)));
2604         encode(e, &b);
2605         freevalfields(&e.val);
2606         return b;
2607 }
2608
2609 int
2610 asn1encodedigest(DigestState* (*fun)(uchar*, ulong, uchar*, DigestState*), uchar *digest, uchar *buf, int len)
2611 {
2612         Bytes *bytes;
2613         DigestAlg **dp;
2614
2615         for(dp = digestalg; *dp != nil; dp++){
2616                 if((*dp)->fun != fun)
2617                         continue;
2618                 bytes = encode_digest(*dp, digest);
2619                 if(bytes == nil)
2620                         break;
2621                 if(bytes->len > len){
2622                         freebytes(bytes);
2623                         break;
2624                 }
2625                 len = bytes->len;
2626                 memmove(buf, bytes->data, len);
2627                 freebytes(bytes);
2628                 return len;
2629         }
2630         return -1;
2631 }
2632
2633 static Elem
2634 mkcont(Elem e, int num)
2635 {
2636         e = mkseq(mkel(e, nil));
2637         e.tag.class = Context;
2638         e.tag.num = num;
2639         return e;
2640 }
2641
2642 static Elem
2643 mkaltname(char *s)
2644 {
2645         Elem e;
2646         int i;
2647
2648         for(i=0; i<nelem(DN_oid); i++){
2649                 if(strstr(s, DN_oid[i].prefix) != nil)
2650                         return mkcont(mkDN(s), 4); /* DN */
2651         }
2652         e = mkstring(s, IA5String);
2653         e.tag.class = Context;
2654         e.tag.num = strchr(s, '@') != nil ? 1 : 2; /* email : DNS */
2655         return e;
2656 }
2657
2658 static Elist*
2659 mkaltnames(char *alts)
2660 {
2661         Elist *el;
2662         char *s, *p;
2663
2664         if(alts == nil)
2665                 return nil;
2666
2667         el = nil;
2668         alts = estrdup(alts);
2669         for(s = alts; s != nil; s = p){
2670                 while(*s == ' ')
2671                         s++;
2672                 if(*s == '\0')
2673                         break;
2674                 if((p = strchr(s, ',')) != nil)
2675                         *p++ = 0;
2676                 el = mkel(mkaltname(s), el);
2677         }
2678         free(alts);
2679         return el;
2680 }
2681
2682 static Elist*
2683 mkextel(Elem e, Ints *oid, Elist *el)
2684 {
2685         Bytes *b = nil;
2686
2687         if(encode(e, &b) == ASN_OK){
2688                 el = mkel(mkseq(
2689                         mkel(mkoid(oid),
2690                         mkel(mkoctet(b->data, b->len),
2691                         nil))), el);
2692                 freebytes(b);
2693         }
2694         freevalfields(&e.val);
2695         return el;
2696 }
2697
2698 static Ints15 oid_subjectAltName = {4, 2, 5, 29, 17 };
2699 static Ints15 oid_extensionRequest = { 7, 1, 2, 840, 113549, 1, 9, 14};
2700
2701 static Elist*
2702 mkextensions(char *alts, int req)
2703 {
2704         Elist *sl, *xl;
2705
2706         xl = nil;
2707         if((sl = mkaltnames(alts)) != nil)
2708                 xl = mkextel(mkseq(sl), (Ints*)&oid_subjectAltName, xl);
2709         if(xl != nil){
2710                 if(req) return mkel(mkcont(mkseq(
2711                         mkel(mkoid((Ints*)&oid_extensionRequest),
2712                         mkel(mkset(mkel(mkseq(xl), nil)), nil))), 0), nil);
2713                 return mkel(mkcont(mkseq(xl), 3), nil);
2714         }
2715         return nil;
2716 }
2717
2718 static char*
2719 splitalts(char *s)
2720 {
2721         int q;
2722
2723         for(q = 0; *s != '\0'; s++){
2724                 if(*s == '\'')
2725                         q ^= 1;
2726                 else if(q == 0 && *s == ','){
2727                         *s++ = 0;
2728                         return s;
2729                 }
2730         }
2731         return nil;
2732 }
2733
2734 static Bytes*
2735 encode_rsapubkey(RSApub *pk)
2736 {
2737         Bytes *b = nil;
2738         Elem e = mkseq(
2739                 mkel(mkbigint(pk->n),
2740                 mkel(mpsignif(pk->ek)<32 ? mkint(mptoi(pk->ek)) : mkbigint(pk->ek),
2741                 nil)));
2742         encode(e, &b);
2743         freevalfields(&e.val);
2744         return b;
2745 }
2746
2747 int
2748 asn1encodeRSApub(RSApub *pk, uchar *buf, int len)
2749 {
2750         Bytes *b = encode_rsapubkey(pk);
2751         if(b == nil)
2752                 return -1;
2753         if(b->len > len){
2754                 freebytes(b);
2755                 werrstr("buffer too small");
2756                 return -1;
2757         }
2758         memmove(buf, b->data, len = b->len);
2759         freebytes(b);
2760         return len;
2761 }
2762
2763 uchar*
2764 X509rsagen(RSApriv *priv, char *subj, ulong valid[2], int *certlen)
2765 {
2766         int serial = 0, sigalg = ALG_sha256WithRSAEncryption;
2767         uchar *cert = nil;
2768         Bytes *certbytes, *pkbytes, *certinfobytes, *sigbytes;
2769         Elem e, certinfo;
2770         DigestAlg *da;
2771         uchar digest[MAXdlen], *buf;
2772         int buflen;
2773         mpint *pkcs1;
2774         char *alts;
2775
2776         if((pkbytes = encode_rsapubkey(&priv->pub)) == nil)
2777                 return nil;
2778
2779         subj = estrdup(subj);
2780         alts = splitalts(subj);
2781
2782         e = mkseq(
2783                 mkel(mkcont(mkint(2), 0),
2784                 mkel(mkint(serial),
2785                 mkel(mkalg(sigalg),
2786                 mkel(mkDN(subj),
2787                 mkel(mkseq(
2788                         mkel(mkutc(valid[0]),
2789                         mkel(mkutc(valid[1]),
2790                         nil))),
2791                 mkel(mkDN(subj),
2792                 mkel(mkseq(
2793                         mkel(mkalg(ALG_rsaEncryption),
2794                         mkel(mkbits(pkbytes->data, pkbytes->len),
2795                         nil))),
2796                 mkextensions(alts, 0)))))))));
2797         freebytes(pkbytes);
2798         if(encode(e, &certinfobytes) != ASN_OK)
2799                 goto errret;
2800
2801         da = digestalg[sigalg];
2802         (*da->fun)(certinfobytes->data, certinfobytes->len, digest, 0);
2803         freebytes(certinfobytes);
2804         certinfo = e;
2805
2806         sigbytes = encode_digest(da, digest);
2807         if(sigbytes == nil)
2808                 goto errret;
2809         pkcs1 = pkcs1padbuf(sigbytes->data, sigbytes->len, priv->pub.n, 1);
2810         freebytes(sigbytes);
2811         if(pkcs1 == nil)
2812                 goto errret;
2813
2814         rsadecrypt(priv, pkcs1, pkcs1);
2815         buflen = mptobe(pkcs1, nil, 0, &buf);
2816         mpfree(pkcs1);
2817         e = mkseq(
2818                 mkel(certinfo,
2819                 mkel(mkalg(sigalg),
2820                 mkel(mkbits(buf, buflen),
2821                 nil))));
2822         free(buf);
2823         if(encode(e, &certbytes) != ASN_OK)
2824                 goto errret;
2825         if(certlen != nil)
2826                 *certlen = certbytes->len;
2827         cert = (uchar*)certbytes;
2828         memmove(cert, certbytes->data, certbytes->len);
2829 errret:
2830         freevalfields(&e.val);
2831         free(subj);
2832         return cert;
2833 }
2834
2835 uchar*
2836 X509rsareq(RSApriv *priv, char *subj, int *certlen)
2837 {
2838         /* RFC 2314, PKCS #10 Certification Request Syntax */
2839         int version = 0, sigalg = ALG_sha256WithRSAEncryption;
2840         uchar *cert = nil;
2841         Bytes *certbytes, *pkbytes, *certinfobytes, *sigbytes;
2842         Elem e, certinfo;
2843         DigestAlg *da;
2844         uchar digest[MAXdlen], *buf;
2845         int buflen;
2846         mpint *pkcs1;
2847         char *alts;
2848
2849         if((pkbytes = encode_rsapubkey(&priv->pub)) == nil)
2850                 return nil;
2851
2852         subj = estrdup(subj);
2853         alts = splitalts(subj);
2854
2855         e = mkseq(
2856                 mkel(mkint(version),
2857                 mkel(mkDN(subj),
2858                 mkel(mkseq(
2859                         mkel(mkalg(ALG_rsaEncryption),
2860                         mkel(mkbits(pkbytes->data, pkbytes->len),
2861                         nil))),
2862                 mkextensions(alts, 1)))));
2863         freebytes(pkbytes);
2864         if(encode(e, &certinfobytes) != ASN_OK)
2865                 goto errret;
2866         da = digestalg[sigalg];
2867         (*da->fun)(certinfobytes->data, certinfobytes->len, digest, 0);
2868         freebytes(certinfobytes);
2869         certinfo = e;
2870
2871         sigbytes = encode_digest(da, digest);
2872         if(sigbytes == nil)
2873                 goto errret;
2874         pkcs1 = pkcs1padbuf(sigbytes->data, sigbytes->len, priv->pub.n, 1);
2875         freebytes(sigbytes);
2876         if(pkcs1 == nil)
2877                 goto errret;
2878
2879         rsadecrypt(priv, pkcs1, pkcs1);
2880         buflen = mptobe(pkcs1, nil, 0, &buf);
2881         mpfree(pkcs1);
2882         e = mkseq(
2883                 mkel(certinfo,
2884                 mkel(mkalg(sigalg),
2885                 mkel(mkbits(buf, buflen),
2886                 nil))));
2887         free(buf);
2888         if(encode(e, &certbytes) != ASN_OK)
2889                 goto errret;
2890         if(certlen != nil)
2891                 *certlen = certbytes->len;
2892         cert = (uchar*)certbytes;
2893         memmove(cert, certbytes->data, certbytes->len);
2894 errret:
2895         freevalfields(&e.val);
2896         free(subj);
2897         return cert;
2898 }
2899
2900 static char*
2901 tagdump(Tag tag)
2902 {
2903         static char buf[32];
2904
2905         if(tag.class != Universal){
2906                 snprint(buf, sizeof(buf), "class%d,num%d", tag.class, tag.num);
2907                 return buf;
2908         }
2909         switch(tag.num){
2910         case BOOLEAN: return "BOOLEAN";
2911         case INTEGER: return "INTEGER";
2912         case BIT_STRING: return "BIT STRING";
2913         case OCTET_STRING: return "OCTET STRING";
2914         case NULLTAG: return "NULLTAG";
2915         case OBJECT_ID: return "OID";
2916         case ObjectDescriptor: return "OBJECT_DES";
2917         case EXTERNAL: return "EXTERNAL";
2918         case REAL: return "REAL";
2919         case ENUMERATED: return "ENUMERATED";
2920         case EMBEDDED_PDV: return "EMBEDDED PDV";
2921         case SEQUENCE: return "SEQUENCE";
2922         case SETOF: return "SETOF";
2923         case UTF8String: return "UTF8String";
2924         case NumericString: return "NumericString";
2925         case PrintableString: return "PrintableString";
2926         case TeletexString: return "TeletexString";
2927         case VideotexString: return "VideotexString";
2928         case IA5String: return "IA5String";
2929         case UTCTime: return "UTCTime";
2930         case GeneralizedTime: return "GeneralizedTime";
2931         case GraphicString: return "GraphicString";
2932         case VisibleString: return "VisibleString";
2933         case GeneralString: return "GeneralString";
2934         case UniversalString: return "UniversalString";
2935         case BMPString: return "BMPString";
2936         default:
2937                 snprint(buf, sizeof(buf), "Universal,num%d", tag.num);
2938                 return buf;
2939         }
2940 }
2941
2942 static void
2943 edump(Elem e)
2944 {
2945         Value v;
2946         Elist *el;
2947         int i;
2948
2949         print("%s{", tagdump(e.tag));
2950         v = e.val;
2951         switch(v.tag){
2952         case VBool: print("Bool %d",v.u.boolval); break;
2953         case VInt: print("Int %d",v.u.intval); break;
2954         case VOctets: print("Octets[%d] %.2x%.2x...",v.u.octetsval->len,v.u.octetsval->data[0],v.u.octetsval->data[1]); break;
2955         case VBigInt: print("BigInt[%d] %.2x%.2x...",v.u.bigintval->len,v.u.bigintval->data[0],v.u.bigintval->data[1]); break;
2956         case VReal: print("Real..."); break;
2957         case VOther: print("Other..."); break;
2958         case VBitString: print("BitString[%d]...", v.u.bitstringval->len*8 - v.u.bitstringval->unusedbits); break;
2959         case VNull: print("Null"); break;
2960         case VEOC: print("EOC..."); break;
2961         case VObjId: print("ObjId");
2962                 for(i = 0; i<v.u.objidval->len; i++)
2963                         print(" %d", v.u.objidval->data[i]);
2964                 break;
2965         case VString: print("String \"%s\"",v.u.stringval); break;
2966         case VSeq: print("Seq\n");
2967                 for(el = v.u.seqval; el!=nil; el = el->tl)
2968                         edump(el->hd);
2969                 break;
2970         case VSet: print("Set\n");
2971                 for(el = v.u.setval; el!=nil; el = el->tl)
2972                         edump(el->hd);
2973                 break;
2974         }
2975         print("}\n");
2976 }
2977
2978 void
2979 asn1dump(uchar *der, int len)
2980 {
2981         Elem e;
2982
2983         if(decode(der, len, &e) != ASN_OK){
2984                 print("didn't parse\n");
2985                 exits("didn't parse");
2986         }
2987         edump(e);
2988 }
2989
2990 void
2991 X509dump(uchar *cert, int ncert)
2992 {
2993         char *e;
2994         CertX509 *c;
2995         RSApub *rsapub;
2996         ECpub *ecpub;
2997         ECdomain ecdom;
2998         int digestlen;
2999         uchar digest[MAXdlen];
3000
3001         print("begin X509dump\n");
3002         c = decode_cert(cert, ncert);
3003         if(c == nil){
3004                 print("cannot decode cert\n");
3005                 return;
3006         }
3007
3008         digestlen = digest_certinfo(cert, ncert, digestalg[c->signature_alg], digest);
3009         if(digestlen <= 0){
3010                 freecert(c);
3011                 print("cannot decode certinfo\n");
3012                 return;
3013         }
3014
3015         print("serial %d\n", c->serial);
3016         print("issuer %s\n", c->issuer);
3017         print("validity %s %s\n", c->validity_start, c->validity_end);
3018         print("subject %s\n", c->subject);
3019         print("sigalg=%d digest=%.*H\n", c->signature_alg, digestlen, digest);
3020         print("publickey_alg=%d pubkey[%d] %.*H\n", c->publickey_alg, c->publickey->len,
3021                 c->publickey->len, c->publickey->data);
3022
3023         switch(c->publickey_alg){
3024         case ALG_rsaEncryption:
3025                 rsapub = asn1toRSApub(c->publickey->data, c->publickey->len);
3026                 if(rsapub != nil){
3027                         print("rsa pubkey e=%B n(%d)=%B\n", rsapub->ek, mpsignif(rsapub->n), rsapub->n);
3028                         e = X509rsaverifydigest(c->signature->data, c->signature->len,
3029                                 digest, digestlen, rsapub);
3030                         if(e==nil)
3031                                 e = "nil (meaning ok)";
3032                         print("self-signed X509rsaverifydigest returns: %s\n", e);
3033                         rsapubfree(rsapub);
3034                 }
3035                 break;
3036         case ALG_ecPublicKey:
3037                 ecdominit(&ecdom, namedcurves[c->curve]);
3038                 ecpub = ecdecodepub(&ecdom, c->publickey->data, c->publickey->len);
3039                 if(ecpub != nil){
3040                         e = X509ecdsaverifydigest(c->signature->data, c->signature->len,
3041                                 digest, digestlen, &ecdom, ecpub);
3042                         if(e==nil)
3043                                 e = "nil (meaning ok)";
3044                         print("self-signed X509ecdsaverifydigest returns: %s\n", e);
3045                         ecpubfree(ecpub);
3046                 }
3047                 ecdomfree(&ecdom);
3048                 break;
3049         }
3050         freecert(c);
3051         print("end X509dump\n");
3052 }