Messages in this thread |  | | | Date | Thu, 02 Dec 2010 16:08:55 -0500 | | Subject | Re: [PATCH] media: rc: ir-lirc-codec: fix potential integer overflow | | From | Andy Walls <> |
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64 bit value / 4 = 62 bit value, right?
Jarod Wilson <jarod@redhat.com> wrote:
>On Thu, Dec 02, 2010 at 07:51:26AM +0300, Dan Carpenter wrote: >> On Fri, Nov 26, 2010 at 08:06:35PM +0300, Vasiliy Kulikov wrote: >> > count = n / sizeof(int); >> > - if (count > LIRCBUF_SIZE || count % 2 == 0) >> > + if (count > LIRCBUF_SIZE || count % 2 == 0 || n % sizeof(int) != 0) >> ^^^^^^^^^^^^^^^^^^^^ >> >> Wait, what? We just checked this a couple lines before. > >Bah. I'd only looked at the diff, which didn't have enough context. I >thought that looked familiar. Indeed, this part seems to be unnecessary. > >> The rest of the patch is right and a clever catch. It would affect >> x86_64 systems and not i386. This doesn't have security implications >> does it? You'd just catch the kmalloc() stack trace for insanely large >> allocations. > >Even on x86_64, it looks to my (relatively untrained) eye like you'd >actually be fine. n is a size_t (so, 64-bit on x86_64). count is an int >(so 32-bit on x86_64). We initialize count to some 64-bit value / 4, so >at most, 16 bits, which always fits just fine in the 32-bit int, no? > >-- >Jarod Wilson >jarod@redhat.com > >-- >To unsubscribe from this list: send the line "unsubscribe linux-media" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html
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