drm/panthor: Prevent potential UAF in group creation

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This commit prevents the possibility of a use after free issue in the
GROUP_CREATE ioctl function, which arose as pointer to the group is
accessed in that ioctl function after storing it in the Xarray.
A malicious userspace can second guess the handle of a group and try
to call GROUP_DESTROY ioctl from another thread around the same time
as GROUP_CREATE ioctl.

To prevent the use after free exploit, this commit uses a mark on an
entry of group pool Xarray which is added just before returning from
the GROUP_CREATE ioctl function. The mark is checked for all ioctls
that specify the group handle and so userspace won't be abe to delete
a group that isn't marked yet.

v2: Add R-bs and fixes tags

Fixes: de85488138 ("drm/panthor: Add the scheduler logical block")
Co-developed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Akash Goel <akash.goel@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: https://patch.msgid.link/20251127164912.3788155-1-akash.goel@arm.com

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This commit is contained in:

Akash Goel 2025-11-27 16:49:12 +00:00 • committed by Boris Brezillon

parent 31d3354f42

commit eec7e23d84

1 changed files with 15 additions and 4 deletions

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drivers/gpu/drm/panthor/panthor_sched.c

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