On Fri, 6 Apr 2012 10:01:36 -0400, Xi Wang xi.wang@gmail.com wrote:
On Apr 6, 2012, at 9:54 AM, Chris Wilson wrote:
On Fri, 6 Apr 2012 09:46:46 -0400, Xi Wang xi.wang@gmail.com wrote:
On Apr 6, 2012, at 9:36 AM, Chris Wilson wrote:
On Fri, 6 Apr 2012 08:58:18 -0400, Xi Wang xi.wang@gmail.com wrote:
A large args->buffer_count from userspace may overflow the allocation size, leading to out-of-bounds access.
Use kmalloc_array() to avoid that.
I can safely say that exec list larger than 4GiB is going to be an illegal operation and would rather the ioctl failed outright with EINVAL.
On 32-bit platform?
On any platform. The largest it can legally be is a few tens of megabytes.
IDGI. First we come to i915_gem_execbuffer2() from ioctl:
exec2_list = kmalloc(sizeof(*exec2_list)*args->buffer_count, ...);
args->buffer_count is passed from userspace so it can be any value.
That I agreed with, I just disagree with how you chose to handle it. Rather than continue on and attempt to vmalloc a large array we should just fail the ioctl with EINVAL. -Chris