[PATCH] md5: fix strict aliasing warnings

[PATCH] md5: fix strict aliasing warnings

[Mike Frysinger]

This is the same fix as was merged in gcc/binutils where this code
appears to originate from.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
 lib/md5.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/md5.c b/lib/md5.c
index 26ec4bb..488d16e 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -138,9 +138,12 @@ void MD5Final(unsigned char digest[MD5LENGTH], struct MD5Context *ctx)
     }
     byteReverse(ctx->in, 14);
 
-    /* Append length in bits and transform */
-    ((uint32_t *) ctx->in)[14] = ctx->bits[0];
-    ((uint32_t *) ctx->in)[15] = ctx->bits[1];
+    /* Append length in bits and transform.
+     * Use memcpy to avoid aliasing problems.  On most systems,
+     * this will be optimized away to the same code.
+     */
+    memcpy(&ctx->in[14 * sizeof(uint32_t)], &ctx->bits[0], 4);
+    memcpy(&ctx->in[15 * sizeof(uint32_t)], &ctx->bits[1], 4);
 
     MD5Transform(ctx->buf, (uint32_t *) ctx->in);
     byteReverse((unsigned char *) ctx->buf, 4);
-- 
1.7.12

Re: [PATCH] md5: fix strict aliasing warnings

[Karel Zak]

On Wed, Oct 10, 2012 at 12:22:38AM -0400, Mike Frysinger wrote:
>  lib/md5.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)

 Applied, thanks! My TODO list shorter now :-)

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com