upstream commit

better translate libcrypto errors by looking deeper in
the accursed error stack for codes that indicate the wrong passphrase was
supplied for a PEM key. bz#2699 ok dtucker@

Upstream-ID: 4da4286326d570f4f0489459bb71f6297e54b681

1 files changed, 62 insertions, 42 deletions

diff --git a/sshkey.c b/sshkey.c
index 9a3f0be58..a138a6f66 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.51 2017/05/31 09:15:42 deraadt Exp $ */
+/* $OpenBSD: sshkey.c,v 1.52 2017/06/09 06:40:24 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -1331,7 +1331,7 @@ sshkey_to_base64(const struct sshkey *key, char **b64p)
         return r;
 }
 
-static int
+int
 sshkey_format_text(const struct sshkey *key, struct sshbuf *b)
 {
         int r = SSH_ERR_INTERNAL_ERROR;
@@ -3366,6 +3366,64 @@ sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
 
 #ifdef WITH_OPENSSL
 static int
+translate_libcrypto_error(unsigned long pem_err)
+{
+        int pem_reason = ERR_GET_REASON(pem_err);
+
+        switch (ERR_GET_LIB(pem_err)) {
+        case ERR_LIB_PEM:
+                switch (pem_reason) {
+                case PEM_R_BAD_PASSWORD_READ:
+                case PEM_R_PROBLEMS_GETTING_PASSWORD:
+                case PEM_R_BAD_DECRYPT:
+                        return SSH_ERR_KEY_WRONG_PASSPHRASE;
+                default:
+                        return SSH_ERR_INVALID_FORMAT;
+                }
+        case ERR_LIB_EVP:
+                switch (pem_reason) {
+                case EVP_R_BAD_DECRYPT:
+                        return SSH_ERR_KEY_WRONG_PASSPHRASE;
+                case EVP_R_BN_DECODE_ERROR:
+                case EVP_R_DECODE_ERROR:
+#ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR
+                case EVP_R_PRIVATE_KEY_DECODE_ERROR:
+#endif
+                        return SSH_ERR_INVALID_FORMAT;
+                default:
+                        return SSH_ERR_LIBCRYPTO_ERROR;
+                }
+        case ERR_LIB_ASN1:
+                return SSH_ERR_INVALID_FORMAT;
+        }
+        return SSH_ERR_LIBCRYPTO_ERROR;
+}
+
+static void
+clear_libcrypto_errors(void)
+{
+        while (ERR_get_error() != 0)
+                ;
+}
+
+/*
+ * Translate OpenSSL error codes to determine whether
+ * passphrase is required/incorrect.
+ */
+static int
+convert_libcrypto_error(void)
+{
+        /*
+         * Some password errors are reported at the beginning
+         * of the error queue.
+         */
+        if (translate_libcrypto_error(ERR_peek_error()) ==
+            SSH_ERR_KEY_WRONG_PASSPHRASE)
+                return SSH_ERR_KEY_WRONG_PASSPHRASE;
+        return translate_libcrypto_error(ERR_peek_last_error());
+}
+
+static int
 sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type,
     const char *passphrase, struct sshkey **keyp)
 {
@@ -3385,48 +3443,10 @@ sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type,
                 goto out;
         }
 
+        clear_libcrypto_errors();
         if ((pk = PEM_read_bio_PrivateKey(bio, NULL, NULL,
             (char *)passphrase)) == NULL) {
-                unsigned long pem_err = ERR_peek_last_error();
-                int pem_reason = ERR_GET_REASON(pem_err);
-
-                /*
-                 * Translate OpenSSL error codes to determine whether
-                 * passphrase is required/incorrect.
-                 */
-                switch (ERR_GET_LIB(pem_err)) {
-                case ERR_LIB_PEM:
-                        switch (pem_reason) {
-                        case PEM_R_BAD_PASSWORD_READ:
-                        case PEM_R_PROBLEMS_GETTING_PASSWORD:
-                        case PEM_R_BAD_DECRYPT:
-                                r = SSH_ERR_KEY_WRONG_PASSPHRASE;
-                                goto out;
-                        default:
-                                r = SSH_ERR_INVALID_FORMAT;
-                                goto out;
-                        }
-                case ERR_LIB_EVP:
-                        switch (pem_reason) {
-                        case EVP_R_BAD_DECRYPT:
-                                r = SSH_ERR_KEY_WRONG_PASSPHRASE;
-                                goto out;
-                        case EVP_R_BN_DECODE_ERROR:
-                        case EVP_R_DECODE_ERROR:
-#ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR
-                        case EVP_R_PRIVATE_KEY_DECODE_ERROR:
-#endif
-                                r = SSH_ERR_INVALID_FORMAT;
-                                goto out;
-                        default:
-                                r = SSH_ERR_LIBCRYPTO_ERROR;
-                                goto out;
-                        }
-                case ERR_LIB_ASN1:
-                        r = SSH_ERR_INVALID_FORMAT;
-                        goto out;
-                }
-                r = SSH_ERR_LIBCRYPTO_ERROR;
+                r = convert_libcrypto_error();
                 goto out;
         }
         if (pk->type == EVP_PKEY_RSA &&