On 09/18/2012 02:13 AM, Geoff Pike wrote:
Hello libiberty experts,
I don't see anything saying that sha1_process_block() has a size limit
on its input buffer, and if the length of the buffer is big (e.g.,
2^32 on a 64-bit machine) then this code won't correctly add a 64-bit
number to 64-bit number:
/* First increment the byte count. RFC 1321 specifies the possible
length of the file up to 2^64 bits. Here we only compute the
number of bytes. Do a double word increment. */
ctx-total[0] += len;
if (ctx-total[0] len)
++ctx-total[1];
The above is at sha1.c around line 302.
I'm not sure if many people read the gcc-bugs list, it's mainly fed from
Bugzilla. Better file a bug.
After a quick look at the code, I'm wondering if the ~63 is properly
sign-extended and then converted to size_t:
sha1_process_block (buffer, len ~63, ctx);
This should work, but it looks a bit fishy.
--
Florian Weimer / Red Hat Product Security Team
