- djm@cvs.openbsd.org 2004/10/29 23:57:05

     [key.c]
     use new buffer API to avoid fatal errors on corrupt keys in authorized_keys
     files; ok markus@

1 files changed, 27 insertions, 11 deletions

diff --git a/key.c b/key.c
index 21b0869df..e41930464 100644
--- a/key.c
+++ b/key.c
@@ -32,7 +32,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "includes.h"
-RCSID("$OpenBSD: key.c,v 1.56 2004/07/28 09:40:29 markus Exp $");
+RCSID("$OpenBSD: key.c,v 1.57 2004/10/29 23:57:05 djm Exp $");
 
 #include <openssl/evp.h>
 
@@ -681,8 +681,8 @@ Key *
 key_from_blob(const u_char *blob, u_int blen)
 {
         Buffer b;
-        char *ktype;
         int rlen, type;
+        char *ktype = NULL;
         Key *key = NULL;
 
 #ifdef DEBUG_PK
@@ -690,24 +690,38 @@ key_from_blob(const u_char *blob, u_int blen)
 #endif
         buffer_init(&b);
         buffer_append(&b, blob, blen);
-        ktype = buffer_get_string(&b, NULL);
+        if ((ktype = buffer_get_string_ret(&b, NULL)) == NULL) {
+                error("key_from_blob: can't read key type");
+                goto out;
+        }
+
         type = key_type_from_name(ktype);
 
         switch (type) {
         case KEY_RSA:
                 key = key_new(type);
-                buffer_get_bignum2(&b, key->rsa->e);
-                buffer_get_bignum2(&b, key->rsa->n);
+                if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 ||
+                    buffer_get_bignum2_ret(&b, key->rsa->n) == -1) {
+                        error("key_from_blob: can't read rsa key");
+                        key_free(key);
+                        key = NULL;
+                        goto out;
+                }
 #ifdef DEBUG_PK
                 RSA_print_fp(stderr, key->rsa, 8);
 #endif
                 break;
         case KEY_DSA:
                 key = key_new(type);
-                buffer_get_bignum2(&b, key->dsa->p);
-                buffer_get_bignum2(&b, key->dsa->q);
-                buffer_get_bignum2(&b, key->dsa->g);
-                buffer_get_bignum2(&b, key->dsa->pub_key);
+                if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 ||
+                    buffer_get_bignum2_ret(&b, key->dsa->q) == -1 ||
+                    buffer_get_bignum2_ret(&b, key->dsa->g) == -1 ||
+                    buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) {
+                        error("key_from_blob: can't read dsa key");
+                        key_free(key);
+                        key = NULL;
+                        goto out;
+                }
 #ifdef DEBUG_PK
                 DSA_print_fp(stderr, key->dsa, 8);
 #endif
@@ -717,12 +731,14 @@ key_from_blob(const u_char *blob, u_int blen)
                 break;
         default:
                 error("key_from_blob: cannot handle type %s", ktype);
-                break;
+                goto out;
         }
         rlen = buffer_len(&b);
         if (key != NULL && rlen != 0)
                 error("key_from_blob: remaining bytes in key blob %d", rlen);
-        xfree(ktype);
+ out:
+        if (ktype != NULL)
+                xfree(ktype);
         buffer_free(&b);
         return key;
 }