factotum: add wpapsk client authentication

diff --git a/sys/src/cmd/auth/factotum/dat.h b/sys/src/cmd/auth/factotum/dat.h
index b36f869e5761e2b18889822db27ffaa24571c612..2652de85a86748b25ea0d82b067dda51c8576b8f 100644 (file)
--- a/sys/src/cmd/auth/factotum/dat.h
+++ b/sys/src/cmd/auth/factotum/dat.h
@@ -237,4 +237,6 @@ extern Proto rsa;                   /* rsa.c */
 extern Proto wep;                      /* wep.c */
 /* extern Proto srs;                   /* srs.c */
 extern Proto httpdigest;               /* httpdigest.c */
-extern Proto ecdsa;
+extern Proto ecdsa;                    /* ecdsa.c */
+extern Proto wpapsk;                   /* wpapsk.c */
+

diff --git a/sys/src/cmd/auth/factotum/fs.c b/sys/src/cmd/auth/factotum/fs.c
index d7b99250705e4e9bf26000f478a7a1e542728487..3093ef3dcea30e31d4dfb7e9a1e4eb7af608e3e9 100644 (file)
--- a/sys/src/cmd/auth/factotum/fs.c
+++ b/sys/src/cmd/auth/factotum/fs.c
@@ -41,6 +41,7 @@ prototab[] =
        &vnc,
        &wep,
        &ecdsa,
+       &wpapsk,
        nil,
 };
 

diff --git a/sys/src/cmd/auth/factotum/mkfile b/sys/src/cmd/auth/factotum/mkfile
index fe1bb1526c94ebd698a88a0b6e886ca9782d8cfa..be34210024c2c1345160a52e9b7106ec1ad78126 100644 (file)
--- a/sys/src/cmd/auth/factotum/mkfile
+++ b/sys/src/cmd/auth/factotum/mkfile
@@ -14,6 +14,7 @@ PROTO=\
        rsa.$O\
        wep.$O\
        ecdsa.$O\
+       wpapsk.$O\
 
 FOFILES=\
        $PROTO\

diff --git a/sys/src/cmd/auth/factotum/wpapsk.c b/sys/src/cmd/auth/factotum/wpapsk.c
new file mode 100644 (file)
index 0000000..785d1c0
--- /dev/null
+++ b/sys/src/cmd/auth/factotum/wpapsk.c
@@ -0,0 +1,237 @@
+/*
+ * WPA-PSK
+ *
+ * Client protocol:
+ *     write challenge: smac[6] + amac[6] + snonce[32] + anonce[32]
+ *     read response: ptk[64]
+ *
+ * Server protocol:
+ *     unimplemented
+ */
+#include "dat.h"
+
+enum {
+       PMKlen = 256/8,
+       PTKlen = 512/8,
+
+       Eaddrlen = 6,
+       Noncelen = 32,
+};
+
+enum
+{
+       CNeedChal,
+       CHaveResp,
+       Maxphase,
+};
+
+static char *phasenames[Maxphase] = {
+[CNeedChal]    "CNeedChal",
+[CHaveResp]    "CHaveResp",
+};
+
+struct State
+{
+       uchar   resp[PTKlen];
+};
+
+static void
+pbkdf2(uchar *p, ulong plen, uchar *s, ulong slen, ulong rounds, uchar *d, ulong dlen)
+{
+       uchar block[SHA1dlen], tmp[SHA1dlen], tmp2[SHA1dlen];
+       ulong i, j, k, n;
+       DigestState *ds;
+
+       for(i = 1; dlen > 0; i++, d += n, dlen -= n){
+               tmp[3] = i;
+               tmp[2] = i >> 8;
+               tmp[1] = i >> 16;
+               tmp[0] = i >> 24;
+               ds = hmac_sha1(s, slen, p, plen, nil, nil);
+               hmac_sha1(tmp, 4, p, plen, block, ds);
+               memmove(tmp, block, sizeof(tmp));
+               for(j = 1; j < rounds; j++){
+                       hmac_sha1(tmp, sizeof(tmp), p, plen, tmp2, nil);
+                       memmove(tmp, tmp2, sizeof(tmp));
+                       for(k=0; k<sizeof(tmp); k++)
+                               block[k] ^= tmp[k];
+               }
+               n = dlen > sizeof(block) ? sizeof(block) : dlen;
+               memmove(d, block, n); 
+       }
+}
+
+static int
+hextob(char *s, char **sp, uchar *b, int n)
+{
+       int r;
+
+       n <<= 1;
+       for(r = 0; r < n && *s; s++){
+               *b <<= 4;
+               if(*s >= '0' && *s <= '9')
+                       *b |= (*s - '0');
+               else if(*s >= 'a' && *s <= 'f')
+                       *b |= 10+(*s - 'a');
+               else if(*s >= 'A' && *s <= 'F')
+                       *b |= 10+(*s - 'A');
+               else break;
+               if((++r & 1) == 0)
+                       b++;
+       }
+       if(sp != nil)
+               *sp = s;
+       return r >> 1;
+}
+
+static void
+pass2pmk(char *pass, char *ssid, uchar pmk[PMKlen])
+{
+       if(hextob(pass, nil, pmk, PMKlen) == PMKlen)
+               return;
+       pbkdf2((uchar*)pass, strlen(pass), (uchar*)ssid, strlen(ssid), 4096, pmk, PMKlen);
+}
+
+static void
+prfn(uchar *k, int klen, char *a, uchar *b, int blen, uchar *d, int dlen)
+{
+       uchar r[SHA1dlen], i;
+       DigestState *ds;
+       int n;
+
+       i = 0;
+       while(dlen > 0){
+               ds = hmac_sha1((uchar*)a, strlen(a)+1, k, klen, nil, nil);
+               hmac_sha1(b, blen, k, klen, nil, ds);
+               hmac_sha1(&i, 1, k, klen, r, ds);
+               i++;
+               n = dlen;
+               if(n > sizeof(r))
+                       n = sizeof(r);
+               memmove(d, r, n); d += n;
+               dlen -= n;
+       }
+}
+
+static void
+calcptk(uchar pmk[PMKlen], uchar smac[Eaddrlen], uchar amac[Eaddrlen], 
+       uchar snonce[Noncelen],  uchar anonce[Noncelen], 
+       uchar ptk[PTKlen])
+{
+       uchar b[2*Eaddrlen + 2*Noncelen];
+
+       if(memcmp(smac, amac, Eaddrlen) > 0){
+               memmove(b + Eaddrlen*0, amac, Eaddrlen);
+               memmove(b + Eaddrlen*1, smac, Eaddrlen);
+       } else {
+               memmove(b + Eaddrlen*0, smac, Eaddrlen);
+               memmove(b + Eaddrlen*1, amac, Eaddrlen);
+       }
+       if(memcmp(snonce, anonce, Eaddrlen) > 0){
+               memmove(b + Eaddrlen*2 + Noncelen*0, anonce, Noncelen);
+               memmove(b + Eaddrlen*2 + Noncelen*1, snonce, Noncelen);
+       } else {
+               memmove(b + Eaddrlen*2 + Noncelen*0, snonce, Noncelen);
+               memmove(b + Eaddrlen*2 + Noncelen*1, anonce, Noncelen);
+       }
+       prfn(pmk, PMKlen, "Pairwise key expansion", b, sizeof(b), ptk, PTKlen);
+}
+
+static int
+wpapskinit(Proto *p, Fsstate *fss)
+{
+       int iscli;
+       State *s;
+
+       if((iscli = isclient(_strfindattr(fss->attr, "role"))) < 0)
+               return failure(fss, nil);
+       if(!iscli)
+               return failure(fss, "%s server not supported", p->name);
+
+       s = emalloc(sizeof *s);
+       fss->phasename = phasenames;
+       fss->maxphase = Maxphase;
+       fss->phase = CNeedChal;
+       fss->ps = s;
+       return RpcOk;
+}
+
+static int
+wpapskwrite(Fsstate *fss, void *va, uint n)
+{
+       uchar pmk[PMKlen], *smac, *amac, *snonce, *anonce;
+       char *pass, *essid;
+       State *s;
+       int ret;
+       Key *k;
+       Keyinfo ki;
+       Attr *attr;
+
+       s = fss->ps;
+
+       if(fss->phase != CNeedChal)
+               return phaseerror(fss, "write");
+       if(n != (2*Eaddrlen + 2*Noncelen))
+               return phaseerror(fss, "bad write size");
+
+       attr = _delattr(_copyattr(fss->attr), "role");
+       mkkeyinfo(&ki, fss, attr);
+       ret = findkey(&k, &ki, "%s", fss->proto->keyprompt);
+       _freeattr(attr);
+       if(ret != RpcOk)
+               return ret;
+
+       pass = _strfindattr(k->privattr, "!password");
+       if(pass == nil)
+               return failure(fss, "key has no password");
+       essid = _strfindattr(k->attr, "essid");
+       if(essid == nil)
+               return failure(fss, "key has no essid");
+       setattrs(fss->attr, k->attr);
+       closekey(k);
+
+       pass2pmk(pass, essid, pmk);
+
+       smac = va;
+       amac = smac + Eaddrlen;
+       snonce = amac + Eaddrlen;
+       anonce = snonce + Noncelen;
+       calcptk(pmk, smac, amac, snonce, anonce, s->resp);
+
+       fss->phase = CHaveResp;
+       return RpcOk;
+}
+
+static int
+wpapskread(Fsstate *fss, void *va, uint *n)
+{
+       State *s;
+
+       s = fss->ps;
+       if(fss->phase != CHaveResp)
+               return phaseerror(fss, "read");
+       if(*n > sizeof(s->resp))
+               *n = sizeof(s->resp);
+       memmove(va, s->resp, *n);
+       fss->phase = Established;
+       fss->haveai = 0;
+       return RpcOk;
+}
+
+static void
+wpapskclose(Fsstate *fss)
+{
+       State *s;
+       s = fss->ps;
+       free(s);
+}
+
+Proto wpapsk = {
+.name=         "wpapsk",
+.init=         wpapskinit,
+.write=                wpapskwrite,
+.read=         wpapskread,
+.close=                wpapskclose,
+.addkey=       replacekey,
+.keyprompt=    "!password? essid?"
+};