upstream commit

don't choke on new-format private keys encrypted with an
 AEAD cipher; bz#2366, patch from Ron Frederick; ok markus@

1 files changed, 11 insertions, 4 deletions

diff --git a/sshkey.c b/sshkey.c
index 3cc3f444a..a36004671 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.16 2015/04/03 22:17:27 djm Exp $ */
+/* $OpenBSD: sshkey.c,v 1.18 2015/05/08 03:17:49 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -3201,7 +3201,7 @@ sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase,
         const u_char *cp;
         int r = SSH_ERR_INTERNAL_ERROR;
         size_t encoded_len;
-        size_t i, keylen = 0, ivlen = 0, slen = 0;
+        size_t i, keylen = 0, ivlen = 0, authlen = 0, slen = 0;
         struct sshbuf *encoded = NULL, *decoded = NULL;
         struct sshbuf *kdf = NULL, *decrypted = NULL;
         struct sshcipher_ctx ciphercontext;
@@ -3311,6 +3311,7 @@ sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase,
         /* setup key */
         keylen = cipher_keylen(cipher);
         ivlen = cipher_ivlen(cipher);
+        authlen = cipher_authlen(cipher);
         if ((key = calloc(1, keylen + ivlen)) == NULL) {
                 r = SSH_ERR_ALLOC_FAIL;
                 goto out;
@@ -3326,19 +3327,25 @@ sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase,
                 }
         }
 
+        /* check that an appropriate amount of auth data is present */
+        if (sshbuf_len(decoded) < encrypted_len + authlen) {
+                r = SSH_ERR_INVALID_FORMAT;
+                goto out;
+        }
+
         /* decrypt private portion of key */
         if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 ||
             (r = cipher_init(&ciphercontext, cipher, key, keylen,
             key + keylen, ivlen, 0)) != 0)
                 goto out;
         if ((r = cipher_crypt(&ciphercontext, 0, dp, sshbuf_ptr(decoded),
-            sshbuf_len(decoded), 0, cipher_authlen(cipher))) != 0) {
+            encrypted_len, 0, authlen)) != 0) {
                 /* an integrity error here indicates an incorrect passphrase */
                 if (r == SSH_ERR_MAC_INVALID)
                         r = SSH_ERR_KEY_WRONG_PASSPHRASE;
                 goto out;
         }
-        if ((r = sshbuf_consume(decoded, encrypted_len)) != 0)
+        if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0)
                 goto out;
         /* there should be no trailing data */
         if (sshbuf_len(decoded) != 0) {