4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> commit ab0d6a141843e0b4b2709dfd37b53468b5452c3a upstream. Handle integer overflow when computing the sub-page length for shmem backed pread/pwrite. Reported-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20181012140228.29783-1-chris@xxxxxxxxxxxxxxxxxx (cherry picked from commit a5e856a5348f6cd50889d125c40bbeec7328e466) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/i915_gem.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1112,11 +1112,7 @@ i915_gem_shmem_pread(struct drm_i915_gem offset = offset_in_page(args->offset); for (idx = args->offset >> PAGE_SHIFT; remain; idx++) { struct page *page = i915_gem_object_get_page(obj, idx); - int length; - - length = remain; - if (offset + length > PAGE_SIZE) - length = PAGE_SIZE - offset; + unsigned int length = min_t(u64, remain, PAGE_SIZE - offset); ret = shmem_pread(page, offset, length, user_data, page_to_phys(page) & obj_do_bit17_swizzling, @@ -1562,11 +1558,7 @@ i915_gem_shmem_pwrite(struct drm_i915_ge offset = offset_in_page(args->offset); for (idx = args->offset >> PAGE_SHIFT; remain; idx++) { struct page *page = i915_gem_object_get_page(obj, idx); - int length; - - length = remain; - if (offset + length > PAGE_SIZE) - length = PAGE_SIZE - offset; + unsigned int length = min_t(u64, remain, PAGE_SIZE - offset); ret = shmem_pwrite(page, offset, length, user_data, page_to_phys(page) & obj_do_bit17_swizzling,
