Vulnerability details

In the Linux kernel, the following vulnerability has been resolved: drm/edid: fix OOB read in drm_parse_tiled_block() 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)

• https://git.kernel.org/stable/c/c4ab04ca1bbf87eefa9fec5c80e1880450d2e7c0
• https://git.kernel.org/stable/c/9acd5c1ddc17ca4c5ffa0c373e3fdf480506e061
• https://git.kernel.org/stable/c/157727131ce8a52d8d9bc676c372ef82db6436c4
• https://git.kernel.org/stable/c/bfa05d89dc3ca3fb1a9099ef5185549a5ec8490d
• https://git.kernel.org/stable/c/4f5484d25f85ad6c989bad5f6a43450cecfcfd28
• https://git.kernel.org/stable/c/9cc0f8e63e8c34cf43def35cbd305ba711181a1f
• https://git.kernel.org/stable/c/4137e1ecec9c8cb6c4fcee28ffabbbc7409eb7fb
• https://git.kernel.org/stable/c/faaa1e1155833e7d4ce7e3cfaf64c0d636b190db