some improvements suggested by djm.

use better constant for salt size.
always copy ":" to gerror, in case somebody is dumb enough to overwrite it
timingsafe_bcmp before somebody whines about strcmp

1 files changed, 6 insertions, 4 deletions

diff --git a/src/lib/libc/crypt/bcrypt.c b/src/lib/libc/crypt/bcrypt.c
index 7070cb7375..7d388cf2ea 100644
--- a/src/lib/libc/crypt/bcrypt.c
+++ b/src/lib/libc/crypt/bcrypt.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bcrypt.c,v 1.33 2014/03/23 23:20:12 tedu Exp $        */
+/*      $OpenBSD: bcrypt.c,v 1.34 2014/03/23 23:25:05 tedu Exp $        */
 
 /*
  * Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
@@ -228,7 +228,8 @@ bcrypt_checkpass(const char *pass, const char *goodhash)
 
         if (bcrypt_hashpass(pass, goodhash, hash, sizeof(hash)) != 0)
                 return -1;
-        if (strcmp(hash, goodhash) != 0)
+        if (strlen(hash) != strlen(goodhash) ||
+            timingsafe_bcmp(hash, goodhash, strlen(goodhash)) != 0)
                 return -1;
         return 0;
 }
@@ -327,7 +328,7 @@ encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
 char *
 bcrypt_gensalt(u_int8_t log_rounds)
 {
-        static char    gsalt[7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1];
+        static char    gsalt[BCRYPT_SALTSPACE];
 
         bcrypt_initsalt(log_rounds, gsalt, sizeof(gsalt));
 
@@ -338,9 +339,10 @@ char *
 bcrypt(const char *pass, const char *salt)
 {
         static char    gencrypted[_PASSWORD_LEN];
-        static char    gerror[] = ":";
+        static char    gerror[2];
 
         /* How do I handle errors ? Return ':' */
+        strlcpy(gerror, ":", sizeof(gerror));
         if (bcrypt_hashpass(pass, salt, gencrypted, sizeof(gencrypted)) != 0)
                 return gerror;