improved checking for invalid hashes. from solar designer

1 files changed, 10 insertions, 6 deletions

diff --git a/src/lib/libc/crypt/bcrypt.c b/src/lib/libc/crypt/bcrypt.c
index d7af344b97..a077c99de5 100644
--- a/src/lib/libc/crypt/bcrypt.c
+++ b/src/lib/libc/crypt/bcrypt.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bcrypt.c,v 1.37 2014/04/08 20:14:25 tedu Exp $        */
+/*      $OpenBSD: bcrypt.c,v 1.38 2014/04/19 15:17:59 tedu Exp $        */
 
 /*
  * Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
@@ -97,11 +97,12 @@ bcrypt_hashpass(const char *key, const char *salt, char *encrypted,
         char arounds[3];
 
         /* Discard "$" identifier */
+        if (*salt != '$')
+                return -1;
         salt++;
 
-        if (*salt > BCRYPT_VERSION) {
+        if (*salt != BCRYPT_VERSION)
                 return -1;
-        }
 
         /* Check for minor versions */
         if (salt[1] != '$') {
@@ -110,6 +111,8 @@ bcrypt_hashpass(const char *key, const char *salt, char *encrypted,
                  case 'b':      /* cap input length at 72 bytes */
                          minor = salt[1];
                          salt++;
+                         if (salt[1] != '$')
+                                 return -1;
                          break;
                  default:
                          return -1;
@@ -141,7 +144,8 @@ bcrypt_hashpass(const char *key, const char *salt, char *encrypted,
                 return -1;
 
         /* We dont want the base64 salt but the raw data */
-        decode_base64(csalt, BCRYPT_MAXSALT, salt);
+        if (decode_base64(csalt, BCRYPT_MAXSALT, salt))
+                return -1;
         salt_len = BCRYPT_MAXSALT;
         if (minor <= 'a')
                 key_len = (u_int8_t)(strlen(key) + (minor >= 'a' ? 1 : 0));
@@ -284,7 +288,7 @@ decode_base64(u_int8_t *buffer, size_t len, const char *b64data)
 
                 c3 = CHAR64(*(p + 2));
                 if (c3 == 255)
-                        break;
+                        return -1;
 
                 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
                 if (bp >= buffer + len)
@@ -292,7 +296,7 @@ decode_base64(u_int8_t *buffer, size_t len, const char *b64data)
 
                 c4 = CHAR64(*(p + 3));
                 if (c4 == 255)
-                        break;
+                        return -1;
                 *bp++ = ((c3 & 0x03) << 6) | c4;
 
                 p += 4;