From: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
At some point, the IEEE ID identification for the replay check in the
AMD EDID was added. However, this check causes the following
out-of-bounds issues when using KASAN:
[ 27.804016] BUG: KASAN: slab-out-of-bounds in amdgpu_dm_update_freesync_caps+0xefa/0x17a0 [amdgpu]
[ 27.804788] Read of size 1 at addr ffff8881647fdb00 by task systemd-udevd/383
...
[ 27.821207] Memory state around the buggy address:
[ 27.821215] ffff8881647fda00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 27.821224] ffff8881647fda80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 27.821234] >ffff8881647fdb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 27.821243] ^
[ 27.821250] ffff8881647fdb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 27.821259] ffff8881647fdc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 27.821268] ==================================================================
This is caused because the ID extraction happens outside of the range of
the edid lenght. This commit addresses this issue by considering the
amd_vsdb_block size.
Cc: ChiaHsuan Chung <chiahsuan.chung@xxxxxxx>
Reviewed-by: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 1d47719e7af1..8381afbe6e4d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -12096,7 +12096,7 @@ static int parse_amd_vsdb(struct amdgpu_dm_connector *aconnector,
break;
}
- while (j < EDID_LENGTH) {
+ while (j < EDID_LENGTH - sizeof(struct amd_vsdb_block)) {
struct amd_vsdb_block *amd_vsdb = (struct amd_vsdb_block *)&edid_ext[j];
unsigned int ieeeId = (amd_vsdb->ieee_id[2] << 16) | (amd_vsdb->ieee_id[1] << 8) | (amd_vsdb->ieee_id[0]);
--
2.46.1
