drm/i915: Sanity check mmap length against object size
authorChris Wilson <chris@chris-wilson.co.uk>
Thu, 14 Mar 2019 07:58:29 +0000 (07:58 +0000)
committerRodrigo Vivi <rodrigo.vivi@intel.com>
Mon, 18 Mar 2019 20:59:42 +0000 (13:59 -0700)
commit000c4f90e3f0194eef218ff2c6a8fd8ca1de4313
tree4bed2fed5f66dbd28c42f7039844489cc27f9a28
parent65f26e978d7c55c3c3d04296058d95cf7b6e3f14
drm/i915: Sanity check mmap length against object size

We assumed that vm_mmap() would reject an attempt to mmap past the end of
the filp (our object), but we were wrong.

Applications that tried to use the mmap beyond the end of the object
would be greeted by a SIGBUS. After this patch, those applications will
be told about the error on creating the mmap, rather than at a random
moment on later access.

Reported-by: Antonio Argenziano <antonio.argenziano@intel.com>
Testcase: igt/gem_mmap/bad-size
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Antonio Argenziano <antonio.argenziano@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190314075829.16838-1-chris@chris-wilson.co.uk
(cherry picked from commit 794a11cb67201ad1bb61af510bb8460280feb3f3)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
drivers/gpu/drm/i915/i915_gem.c