pull updated OpenBSD BCrypt PBKDF implementation
Includes fix for 1 byte output overflow for large key length
requests (not reachable in OpenSSH).
Pointed out by Joshua Rogers
diff --git a/openbsd-compat/bcrypt_pbkdf.c b/openbsd-compat/bcrypt_pbkdf.c
index 91b6ba0..5ed1cc5 100644
--- a/openbsd-compat/bcrypt_pbkdf.c
+++ b/openbsd-compat/bcrypt_pbkdf.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bcrypt_pbkdf.c,v 1.4 2013/07/29 00:55:53 tedu Exp $ */
+/* $OpenBSD: bcrypt_pbkdf.c,v 1.9 2014/07/13 21:21:25 tedu Exp $ */
/*
* Copyright (c) 2013 Ted Unangst <tedu@openbsd.org>
*
@@ -51,8 +51,8 @@
*
* One modification from official pbkdf2. Instead of outputting key material
* linearly, we mix it. pbkdf2 has a known weakness where if one uses it to
- * generate (i.e.) 512 bits of key material for use as two 256 bit keys, an
- * attacker can merely run once through the outer loop below, but the user
+ * generate (e.g.) 512 bits of key material for use as two 256 bit keys, an
+ * attacker can merely run once through the outer loop, but the user
* always runs it twice. Shuffling output bytes requires computing the
* entirety of the key material to assemble any subkey. This is something a
* wise caller could do; we just do it for you.
@@ -97,9 +97,9 @@
}
/* zap */
- memset(ciphertext, 0, sizeof(ciphertext));
- memset(cdata, 0, sizeof(cdata));
- memset(&state, 0, sizeof(state));
+ explicit_bzero(ciphertext, sizeof(ciphertext));
+ explicit_bzero(cdata, sizeof(cdata));
+ explicit_bzero(&state, sizeof(state));
}
int
@@ -113,6 +113,7 @@
u_int8_t *countsalt;
size_t i, j, amt, stride;
uint32_t count;
+ size_t origkeylen = keylen;
/* nothing crazy */
if (rounds < 1)
@@ -155,14 +156,17 @@
* pbkdf2 deviation: ouput the key material non-linearly.
*/
amt = MIN(amt, keylen);
- for (i = 0; i < amt; i++)
- key[i * stride + (count - 1)] = out[i];
- keylen -= amt;
+ for (i = 0; i < amt; i++) {
+ size_t dest = i * stride + (count - 1);
+ if (dest >= origkeylen)
+ break;
+ key[dest] = out[i];
+ }
+ keylen -= i;
}
/* zap */
- memset(out, 0, sizeof(out));
- memset(countsalt, 0, saltlen + 4);
+ explicit_bzero(out, sizeof(out));
free(countsalt);
return 0;