improved checking for invalid hashes. from solar designer

diff --git a/lib/libc/crypt/bcrypt.c b/lib/libc/crypt/bcrypt.c
index d7af344..a077c99 100644 (file)
--- a/lib/libc/crypt/bcrypt.c
+++ b/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;