- djm@cvs.openbsd.org 2010/07/16 14:07:35
[ssh-rsa.c]
more timing paranoia - compare all parts of the expected decrypted
data before returning. AFAIK not exploitable in the SSH protocol.
"groovy" deraadt@
diff --git a/ssh-rsa.c b/ssh-rsa.c
index e3f1561..c471ff3 100644
--- a/ssh-rsa.c
+++ b/ssh-rsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-rsa.c,v 1.43 2010/07/13 23:13:16 djm Exp $ */
+/* $OpenBSD: ssh-rsa.c,v 1.44 2010/07/16 14:07:35 djm Exp $ */
/*
* Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org>
*
@@ -211,7 +211,7 @@
u_char *sigbuf, u_int siglen, RSA *rsa)
{
u_int ret, rsasize, oidlen = 0, hlen = 0;
- int len;
+ int len, oidmatch, hashmatch;
const u_char *oid = NULL;
u_char *decrypted = NULL;
@@ -250,11 +250,13 @@
error("bad decrypted len: %d != %d + %d", len, hlen, oidlen);
goto done;
}
- if (timingsafe_bcmp(decrypted, oid, oidlen) != 0) {
+ oidmatch = timingsafe_bcmp(decrypted, oid, oidlen) == 0;
+ hashmatch = timingsafe_bcmp(decrypted + oidlen, hash, hlen) == 0;
+ if (!oidmatch) {
error("oid mismatch");
goto done;
}
- if (timingsafe_bcmp(decrypted + oidlen, hash, hlen) != 0) {
+ if (!hashmatch) {
error("hash mismatch");
goto done;
}