upstream commit

Refuse RSA keys <1024 bits in length. Improve reporting
for keys that do not meet this requirement. ok markus@

Upstream-ID: b385e2a7b13b1484792ee681daaf79e1e203df6c

1 files changed, 24 insertions, 5 deletions

diff --git a/sshkey.c b/sshkey.c
index 0f6468197..6518c6f0b 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.48 2017/04/30 23:18:44 djm Exp $ */
+/* $OpenBSD: sshkey.c,v 1.49 2017/05/07 23:15:59 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -1392,10 +1392,11 @@ rsa_generate_private_key(u_int bits, RSA **rsap)
         BIGNUM *f4 = NULL;
         int ret = SSH_ERR_INTERNAL_ERROR;
 
-        if (rsap == NULL ||
-            bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
-            bits > SSHBUF_MAX_BIGNUM * 8)
+        if (rsap == NULL)
                 return SSH_ERR_INVALID_ARGUMENT;
+        if (bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
+            bits > SSHBUF_MAX_BIGNUM * 8)
+                return SSH_ERR_KEY_LENGTH;
         *rsap = NULL;
         if ((private = RSA_new()) == NULL || (f4 = BN_new()) == NULL) {
                 ret = SSH_ERR_ALLOC_FAIL;
@@ -1423,8 +1424,10 @@ dsa_generate_private_key(u_int bits, DSA **dsap)
         DSA *private;
         int ret = SSH_ERR_INTERNAL_ERROR;
 
-        if (dsap == NULL || bits != 1024)
+        if (dsap == NULL)
                 return SSH_ERR_INVALID_ARGUMENT;
+        if (bits != 1024)
+                return SSH_ERR_KEY_LENGTH;
         if ((private = DSA_new()) == NULL) {
                 ret = SSH_ERR_ALLOC_FAIL;
                 goto out;
@@ -1876,6 +1879,10 @@ sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp,
                         ret = SSH_ERR_INVALID_FORMAT;
                         goto out;
                 }
+                if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+                        ret = SSH_ERR_KEY_LENGTH;
+                        goto out;
+                }
 #ifdef DEBUG_PK
                 RSA_print_fp(stderr, key->rsa, 8);
 #endif
@@ -2643,6 +2650,10 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
                     (r = sshbuf_get_bignum2(buf, k->rsa->q)) != 0 ||
                     (r = rsa_generate_additional_parameters(k->rsa)) != 0)
                         goto out;
+                if (BN_num_bits(k->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+                        r = SSH_ERR_KEY_LENGTH;
+                        goto out;
+                }
                 break;
         case KEY_RSA_CERT:
                 if ((r = sshkey_froms(buf, &k)) != 0 ||
@@ -2653,6 +2664,10 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
                     (r = sshbuf_get_bignum2(buf, k->rsa->q)) != 0 ||
                     (r = rsa_generate_additional_parameters(k->rsa)) != 0)
                         goto out;
+                if (BN_num_bits(k->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+                        r = SSH_ERR_KEY_LENGTH;
+                        goto out;
+                }
                 break;
 #endif /* WITH_OPENSSL */
         case KEY_ED25519:
@@ -3427,6 +3442,10 @@ sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type,
                         r = SSH_ERR_LIBCRYPTO_ERROR;
                         goto out;
                 }
+                if (BN_num_bits(prv->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+                        r = SSH_ERR_KEY_LENGTH;
+                        goto out;
+                }
         } else if (pk->type == EVP_PKEY_DSA &&
             (type == KEY_UNSPEC || type == KEY_DSA)) {
                 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {