OpenBSD bcrypt return value on errors

[Loganaden Velvindron]

According to http://www.openwall.com/lists/oss-security/2011/11/15/3,
it would be preferable to use something else than ':' when an error
is encountered.

According to crypt(3), crypt() should return NULL values on errors.

Index: src/lib/libc/crypt/bcrypt.c
===================================================================
RCS file: /cvs/src/lib/libc/crypt/bcrypt.c,v
retrieving revision 1.24
diff -u -p -r1.24 bcrypt.c
--- src/lib/libc/crypt/bcrypt.c 2 Apr 2008 19:54:05 -0000       1.24
+++ src/lib/libc/crypt/bcrypt.c 26 Feb 2012 05:19:27 -0000
@@ -70,7 +70,6 @@ static void decode_base64(u_int8_t *, u_
 
 static char    encrypted[_PASSWORD_LEN];
 static char    gsalt[7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1];
-static char    error[] = ":";
 
 const static u_int8_t Base64Code[] =
 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
@@ -185,8 +184,9 @@ bcrypt(const char *key, const char *salt
        salt++;
 
        if (*salt > BCRYPT_VERSION) {
-               /* How do I handle errors ? Return ':' */
-               return error;
+               /* How do I handle errors ? Return NULL according to
+                  crypt(3) */
+               return NULL;
        }
 
        /* Check for minor versions */
@@ -198,7 +198,7 @@ bcrypt(const char *key, const char *salt
                         salt++;
                         break;
                 default:
-                        return error;
+                        return NULL;
                 }
        } else
                 minor = 0;
@@ -208,21 +208,21 @@ bcrypt(const char *key, const char *salt
 
        if (salt[2] != '$')
                /* Out of sync with passwd entry */
-               return error;
+               return NULL;
 
        /* Computer power doesn't increase linear, 2^x should be fine */
        n = atoi(salt);
        if (n > 31 || n < 0)
-               return error;
+               return NULL;
        logr = (u_int8_t)n;
        if ((rounds = (u_int32_t) 1 << logr) < BCRYPT_MINROUNDS)
-               return error;
+               return NULL;
 
        /* Discard num rounds + "$" identifier */
        salt += 3;
 
        if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
-               return error;
+               return NULL;
 
        /* We dont want the base64 salt but the raw data */
        decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt);