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| author | Imre Deak <imre.deak@intel.com> | 2024-11-25 22:53:14 +0200 |
|---|---|---|
| committer | Imre Deak <imre.deak@intel.com> | 2024-11-26 14:44:59 +0200 |
| commit | bd2fccac61b40eaf08d9546acc9fef958bfe4763 (patch) | |
| tree | e31ffc773f8a38fd7a47b0e27a76d4cc640d2218 /drivers/gpu/drm | |
| parent | 78ac1c3558810486d90aa533b0039aa70487a3da (diff) | |
drm/dp_mst: Fix MST sideband message body length check
Fix the MST sideband message body length check, which must be at least 1
byte accounting for the message body CRC (aka message data CRC) at the
end of the message.
This fixes a case where an MST branch device returns a header with a
correct header CRC (indicating a correctly received body length), with
the body length being incorrectly set to 0. This will later lead to a
memory corruption in drm_dp_sideband_append_payload() and the following
errors in dmesg:
UBSAN: array-index-out-of-bounds in drivers/gpu/drm/display/drm_dp_mst_topology.c:786:25
index -1 is out of range for type 'u8 [48]'
Call Trace:
drm_dp_sideband_append_payload+0x33d/0x350 [drm_display_helper]
drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper]
drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper]
memcpy: detected field-spanning write (size 18446744073709551615) of single field "&msg->msg[msg->curlen]" at drivers/gpu/drm/display/drm_dp_mst_topology.c:791 (size 256)
Call Trace:
drm_dp_sideband_append_payload+0x324/0x350 [drm_display_helper]
drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper]
drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper]
Cc: <stable@vger.kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241125205314.1725887-1-imre.deak@intel.com
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_mst_topology.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index ac90118b9e7a..e6ee180815b2 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -320,6 +320,9 @@ static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr hdr->broadcast = (buf[idx] >> 7) & 0x1; hdr->path_msg = (buf[idx] >> 6) & 0x1; hdr->msg_len = buf[idx] & 0x3f; + if (hdr->msg_len < 1) /* min space for body CRC */ + return false; + idx++; hdr->somt = (buf[idx] >> 7) & 0x1; hdr->eomt = (buf[idx] >> 6) & 0x1; |