From: Xiang Mei <xmei5@asu.edu> stable inclusion from stable-v5.10.261 commit c4ab04ca1bbf87eefa9fec5c80e1880450d2e7c0 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16848 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit faaa1e1155833e7d4ce7e3cfaf64c0d636b190db ] drm_parse_tiled_block() casts the DisplayID block to a struct displayid_tiled_block and reads the full fixed layout up to tile->topology_id[7] without checking block->num_bytes. The DisplayID iterator only validates the declared payload length, so a crafted EDID can advertise a tiled-display block (tag DATA_BLOCK_TILED_DISPLAY, or DATA_BLOCK_2_TILED_DISPLAY_TOPOLOGY for v2.0) with a small num_bytes at the end of a DisplayID extension. The read then runs past the end of the exact-sized kmemdup()'d EDID allocation, a heap out-of-bounds read. Reject blocks shorter than the spec's 22-byte tiled payload before reading the fixed struct, as drm_parse_vesa_mso_data() already does. BUG: KASAN: slab-out-of-bounds in drm_edid_connector_update Read of size 2 at addr ffff888010077700 by task exploit/147 dump_stack_lvl (lib/dump_stack.c:94 ...) print_report (mm/kasan/report.c:378 ...) kasan_report (mm/kasan/report.c:595) drm_edid_connector_update (drivers/gpu/drm/drm_edid.c:7581) bochs_connector_helper_get_modes (drivers/gpu/drm/tiny/bochs.c:574) drm_helper_probe_single_connector_modes (drivers/gpu/drm/drm_probe_helper.c:426) status_store (drivers/gpu/drm/drm_sysfs.c:219) ... vfs_write (fs/read_write.c:595 fs/read_write.c:688) ksys_write (fs/read_write.c:740) Fixes: 40d9b043a89e ("drm/connector: store tile information from displayid (v3)") Reported-by: Weiming Shi <bestswngs@gmail.com> Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei <xmei5@asu.edu> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Link: https://patch.msgid.link/20260615184737.899892-1-xmei5@asu.edu Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zhang Hongtao <zhanghongtao35@huawei.com> --- drivers/gpu/drm/drm_edid.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index f5926bf5dabd9..ad7e524d03037 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5198,6 +5198,13 @@ static int drm_parse_tiled_block(struct drm_connector *connector, u8 num_v_tile, num_h_tile; struct drm_tile_group *tg; + /* tiled block payload per spec: cap 1 + topo 3 + size 4 + bezel 5 + id 9 = 22 */ + if (block->num_bytes < 22) { + DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Unexpected tiled block size %u\n", + connector->base.id, connector->name, block->num_bytes); + return 0; + } + w = tile->tile_size[0] | tile->tile_size[1] << 8; h = tile->tile_size[2] | tile->tile_size[3] << 8; -- 2.43.0