In order to prevent a potential NULL deference with hostile userspace, we need to check whether the ioctl was passed an invalid args pointer.
Reported-by: Tommi Rantala tt.rantala@gmail.com Link: http://lkml.kernel.org/r/CA+ydwtpuBvbwxbt-tdgPUvj1EU7itmCHo_2B3w13HkD5+jWKow... Signed-off-by: Chris Wilson chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index 365e41a..9f5602e 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -1103,7 +1103,11 @@ i915_gem_execbuffer(struct drm_device *dev, void *data, struct drm_i915_gem_exec_object2 *exec2_list = NULL; int ret, i;
- if (args->buffer_count < 1) { + if (args == NULL) + return -EINVAL; + + if (args->buffer_count < 1 || + args->buffer_count > INT_MAX / sizeof(*exec2_list)) { DRM_DEBUG("execbuf with %d buffers\n", args->buffer_count); return -EINVAL; } @@ -1182,8 +1186,11 @@ i915_gem_execbuffer2(struct drm_device *dev, void *data, struct drm_i915_gem_exec_object2 *exec2_list = NULL; int ret;
+ if (args == NULL) + return -EINVAL; + if (args->buffer_count < 1 || - args->buffer_count > UINT_MAX / sizeof(*exec2_list)) { + args->buffer_count > INT_MAX / sizeof(*exec2_list)) { DRM_DEBUG("execbuf2 with %d buffers\n", args->buffer_count); return -EINVAL; }