On Dec 2, 2010, at 10:00 AM, Jarod Wilson 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? Never mind, I shouldn't be allowed near computers on too little sleep. Its been pointed out to me how incredibly incorrect and stupid what I said above is. :) (i.e., we're not dividing the bits by 4, we're dividing a 64-bit value by 4, so you're still in 62-bit territory.) /me sticks head back in sand -- Jarod Wilson jarod@xxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
