Add error checking to publickey_make_dss().

git-svn-id: svn+ssh://svn.berlios.de/svnroot/repos/libssh/trunk@429 7dcaeef0-15fb-0310-b436-a5af3365683c

libssh/keys.c

@@ -67,8 +67,11 @@ int ssh_type_from_name(const char *name) {
 }
 
 PUBLIC_KEY *publickey_make_dss(SSH_SESSION *session, BUFFER *buffer) {
-    STRING *p,*q,*g,*pubkey;
+  STRING *p = NULL;
-    PUBLIC_KEY *key;
+  STRING *q = NULL;
+  STRING *g = NULL;
+  STRING *pubkey = NULL;
+  PUBLIC_KEY *key = NULL;
 
   key = malloc(sizeof(PUBLIC_KEY));
   if (key == NULL) {
@@ -77,37 +80,68 @@ PUBLIC_KEY *publickey_make_dss(SSH_SESSION *session, BUFFER *buffer){
 
   key->type=TYPE_DSS;
   key->type_c="ssh-dss";
+
   p = buffer_get_ssh_string(buffer);
   q = buffer_get_ssh_string(buffer);
   g = buffer_get_ssh_string(buffer);
   pubkey = buffer_get_ssh_string(buffer);
+
   buffer_free(buffer); /* we don't need it anymore */
-    if(!p || !q || !g || !pubkey){
+
+  if (p == NULL || q == NULL || g == NULL || pubkey == NULL) {
     ssh_set_error(session, SSH_FATAL, "Invalid DSA public key");
-        if(p)
+    goto error;
-            free(p);
-        if(q)
-            free(q);
-        if(g)
-            free(g);
-        if(pubkey)
-            free(pubkey);
-        free(key);
-        return NULL;
   }
+
 #ifdef HAVE_LIBGCRYPT
-    gcry_sexp_build(&key->dsa_pub,NULL,"(public-key(dsa(p %b)(q %b)(g %b)(y %b)))",string_len(p),p->string,string_len(q),q->string,string_len(g),g->string,string_len(pubkey),pubkey->string);
+  gcry_sexp_build(&key->dsa_pub, NULL,
+      "(public-key(dsa(p %b)(q %b)(g %b)(y %b)))",
+      string_len(p), p->string,
+      string_len(q), q->string,
+      string_len(g), g->string,
+      string_len(pubkey), pubkey->string);
+  if (key->dsa_pub == NULL) {
+    goto error;
+  }
 #elif defined HAVE_LIBCRYPTO
+
   key->dsa_pub = DSA_new();
+  if (key->dsa_pub == NULL) {
+    goto error;
+  }
   key->dsa_pub->p = make_string_bn(p);
   key->dsa_pub->q = make_string_bn(q);
   key->dsa_pub->g = make_string_bn(g);
   key->dsa_pub->pub_key = make_string_bn(pubkey);
-#endif
+  if (key->dsa_pub->p == NULL ||
-    free(p);
+      key->dsa_pub->q == NULL ||
-    free(q);
+      key->dsa_pub->g == NULL ||
-    free(g);
+      key->dsa_pub->pub_key == NULL) {
-    free(pubkey);
+    goto error;
+  }
+#endif /* HAVE_LIBCRYPTO */
+
+  string_burn(p);
+  string_free(p);
+  string_burn(q);
+  string_free(q);
+  string_burn(g);
+  string_free(g);
+  string_burn(pubkey);
+  string_free(pubkey);
+
+  return key;
+error:
+  string_burn(p);
+  string_free(p);
+  string_burn(q);
+  string_free(q);
+  string_burn(g);
+  string_free(g);
+  string_burn(pubkey);
+  string_free(pubkey);
+  publickey_free(key);
+
   return key;
 }