Bug#634696: (no subject)

[David Miller <davem@davemloft.net>]

The problem is how sha1.cc codes the SHA1 transform, it illegally
casts the on-stack workspace buffer to a type requiring more
alignment than 'workspace' is actually declared to have.

This only shows up recently because gcc-4.6 now does a really
aggressive optimization where it gets rid of the workspace
buffer entirely and just accesses 'buffer' directly, and assumes
it has the necessary alignment for 32-bit loads (which it
doesn't).

This patch fixes the bug:

--- apt-pkg/contrib/sha1.cc~	2011-06-17 03:10:20.000000000 -0700
+++ apt-pkg/contrib/sha1.cc	2011-07-25 15:16:26.774548017 -0700
@@ -74,10 +74,9 @@ static void SHA1Transform(uint32_t state
       uint32_t l[16];
    }
    CHAR64LONG16;
-   CHAR64LONG16 *block;
+   CHAR64LONG16 workspace, *block;
 
-   uint8_t workspace[64];
-   block = (CHAR64LONG16 *)workspace;
+   block = &workspace;
    memcpy(block,buffer,sizeof(workspace));
 
    /* Copy context->state[] to working vars */