[PATCH] Fix PPC SHA1 routine for large input buffers

From: Paul Mackerras <paulus@samba.org>
Date: Jun 18, 2006, 23:25 UTC
Message-ID: <17557.57564.267469.561683@cargo.ozlabs.ibm.com>
In-Reply-To: <Pine.LNX.4.64.0606181543270.5498@g5.osdl.org>

The PPC SHA1 routine had an overflow which meant that it gave incorrect results for input buffers >= 512MB. This fixes it by ensuring that the update of the total length in bits is done using 64-bit arithmetic.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
Linus Torvalds writes:

> Paul - I think the ppc SHA1_Update() overflows in 32 bits, when the length 
> of the memory area to be checksummed is huge.

Yep. I checked the assembly output of this, and it looks right, but I haven't actually tested it by running it...

Paul.

diff --git a/ppc/sha1.c b/ppc/sha1.c
index 5ba4fc5..0820398 100644
--- a/ppc/sha1.c
+++ b/ppc/sha1.c
@@ -30,7 +30,7 @@ int SHA1_Update(SHA_CTX *c, const void *
 	unsigned long nb;
 	const unsigned char *p = ptr;
 
-	c->len += n << 3;
+	c->len += (uint64_t) n << 3;
 	while (n != 0) {
 		if (c->cnt || n < 64) {
 			nb = 64 - c->cnt;