devenv: prevent non-hostowner from creating or removing variables in '#ec', cleanup

diff --git a/sys/src/9/port/devenv.c b/sys/src/9/port/devenv.c
index e7100aa4ad2fb2e4d5b22e40210b90b5fb881652..af0dbc12a4afc527bdaa90a245d29c9131bd3c0a 100644 (file)
--- a/sys/src/9/port/devenv.c
+++ b/sys/src/9/port/devenv.c
@@ -23,7 +23,7 @@ envlookup(Egrp *eg, char *name, ulong qidpath)
 
        for(i=0; i<eg->nent; i++){
                e = eg->ent[i];
-               if(e->qid.path == qidpath || (name && e->name[0]==name[0] && strcmp(e->name, name) == 0))
+               if(e->qid.path == qidpath || (name != nil && name[0] == e->name[0] && strcmp(e->name, name) == 0))
                        return e;
        }
        return nil;
@@ -42,13 +42,13 @@ envgen(Chan *c, char *name, Dirtab*, int, int s, Dir *dp)
 
        eg = envgrp(c);
        rlock(eg);
-       e = 0;
-       if(name)
+       e = nil;
+       if(name != nil)
                e = envlookup(eg, name, -1);
        else if(s < eg->nent)
                e = eg->ent[s];
 
-       if(e == 0 || name && (strlen(e->name) >= sizeof(up->genbuf))) {
+       if(e == nil || name != nil && (strlen(e->name) >= sizeof(up->genbuf))) {
                runlock(eg);
                return -1;
        }
@@ -66,11 +66,10 @@ envattach(char *spec)
        Chan *c;
        Egrp *egrp = nil;
 
-       if(spec && *spec) {
-               if(strcmp(spec, "c") == 0)
-                       egrp = &confegrp;
-               if(egrp == nil)
+       if(spec != nil && *spec != '\0') {
+               if(strcmp(spec, "c") != 0)
                        error(Ebadarg);
+               egrp = &confegrp;
        }
 
        c = devattach('e', spec);
@@ -113,17 +112,17 @@ envopen(Chan *c, int omode)
                else
                        rlock(eg);
                e = envlookup(eg, nil, c->qid.path);
-               if(e == 0) {
+               if(e == nil) {
                        if(trunc)
                                wunlock(eg);
                        else
                                runlock(eg);
                        error(Enonexist);
                }
-               if(trunc && e->value) {
+               if(trunc && e->value != nil) {
                        e->qid.vers++;
                        free(e->value);
-                       e->value = 0;
+                       e->value = nil;
                        e->len = 0;
                }
                if(trunc)
@@ -144,7 +143,7 @@ envcreate(Chan *c, char *name, int omode, ulong)
        Evalue *e;
        Evalue **ent;
 
-       if(c->qid.type != QTDIR)
+       if(c->qid.type != QTDIR || !envwriteable(c))
                error(Eperm);
 
        if(strlen(name) >= sizeof(up->genbuf))
@@ -159,7 +158,7 @@ envcreate(Chan *c, char *name, int omode, ulong)
                nexterror();
        }
 
-       if(envlookup(eg, name, -1))
+       if(envlookup(eg, name, -1) != nil)
                error(Eexist);
 
        e = smalloc(sizeof(Evalue));
@@ -196,12 +195,12 @@ envremove(Chan *c)
        Egrp *eg;
        Evalue *e;
 
-       if(c->qid.type & QTDIR)
+       if(c->qid.type & QTDIR || !envwriteable(c))
                error(Eperm);
 
        eg = envgrp(c);
        wlock(eg);
-       e = 0;
+       e = nil;
        for(i=0; i<eg->nent; i++){
                if(eg->ent[i]->qid.path == c->qid.path){
                        e = eg->ent[i];
@@ -212,11 +211,10 @@ envremove(Chan *c)
                }
        }
        wunlock(eg);
-       if(e == 0)
+       if(e == nil)
                error(Enonexist);
        free(e->name);
-       if(e->value)
-               free(e->value);
+       free(e->value);
        free(e);
 }
 
@@ -245,12 +243,12 @@ envread(Chan *c, void *a, long n, vlong off)
        eg = envgrp(c);
        rlock(eg);
        e = envlookup(eg, nil, c->qid.path);
-       if(e == 0) {
+       if(e == nil) {
                runlock(eg);
                error(Enonexist);
        }
 
-       if(offset > e->len)     /* protects against overflow converting vlong to ulong */
+       if(offset >= e->len || e->value == nil)
                n = 0;
        else if(offset + n > e->len)
                n = e->len - offset;
@@ -279,7 +277,7 @@ envwrite(Chan *c, void *a, long n, vlong off)
        eg = envgrp(c);
        wlock(eg);
        e = envlookup(eg, nil, c->qid.path);
-       if(e == 0) {
+       if(e == nil) {
                wunlock(eg);
                error(Enonexist);
        }
@@ -291,7 +289,7 @@ envwrite(Chan *c, void *a, long n, vlong off)
                        wunlock(eg);
                        error(Enomem);
                }
-               if(e->value){
+               if(e->value != nil){
                        memmove(s, e->value, e->len);
                        free(e->value);
                }
@@ -340,7 +338,7 @@ envcpy(Egrp *to, Egrp *from)
                ne = smalloc(sizeof(Evalue));
                ne->name = smalloc(strlen(e->name)+1);
                strcpy(ne->name, e->name);
-               if(e->value){
+               if(e->value != nil){
                        ne->value = smalloc(e->len);
                        memmove(ne->value, e->value, e->len);
                        ne->len = e->len;
@@ -362,8 +360,7 @@ closeegrp(Egrp *eg)
                for(i=0; i<eg->nent; i++){
                        e = eg->ent[i];
                        free(e->name);
-                       if(e->value)
-                               free(e->value);
+                       free(e->value);
                        free(e);
                }
                free(eg->ent);
@@ -382,7 +379,7 @@ envgrp(Chan *c)
 static int
 envwriteable(Chan *c)
 {
-       return iseve() || c->aux == nil;
+       return c->aux == nil || c->aux == up->egrp || iseve();
 }
 
 /*
@@ -438,7 +435,7 @@ getconfenv(void)
                /* move up to the first null */
                q += strlen(q) + 1;
        }
-       *q = 0;
+       *q = '\0';
        
        poperror();
        runlock(eg);