On 32-bit systems, a large args->num_cliprects from userspace via ioctl
may overflow the allocation size, leading to out-of-bounds access.
This vulnerability was introduced in commit 432e58ed ("drm/i915: Avoid
allocation for execbuffer object list").
Signed-off-by: Xi Wang <xi.w...@gmail.com>
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: sta...@vger.kernel.org
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 7c50e58..de43194 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1133,6 +1133,11 @@ i915_gem_do_execbuffer(struct drm_device *dev, void
*data,
return -EINVAL;
}
+ if (args->num_cliprects > UINT_MAX / sizeof(*cliprects)) {
+ DRM_DEBUG("execbuf with %u cliprects\n",
+ args->num_cliprects);
+ return -EINVAL;
+ }
cliprects = kmalloc(args->num_cliprects * sizeof(*cliprects),
GFP_KERNEL);
if (cliprects == NULL) {
--
1.7.5.4
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