diff options
| author | Harry Wentland <harry.wentland@amd.com> | 2026-05-07 15:38:37 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2026-06-03 13:38:01 -0400 |
| commit | 229212219e4247d9486f8ba41ef087358490be09 (patch) | |
| tree | 668a3ab94331609391e838f5344bc6f2612ff287 /drivers/gpu | |
| parent | eadf438ab8d370b9d19acee9359918c85afeb80d (diff) | |
drm/amd/display: Clamp HDMI HDCP2 rx_id_list read to buffer size
[Why & How]
During HDCP 2.x repeater authentication over HDMI, the driver reads the
sink's RxStatus register and extracts a 10-bit message size field (max
value 1023). This value is used as the read length for the ReceiverID
list without being clamped to the size of the destination buffer
rx_id_list[177]. A malicious HDMI repeater could advertise a message
size larger than the buffer, causing an out-of-bounds write during the
I2C read.
Clamp the read length in mod_hdcp_read_rx_id_list() to the size of the
rx_id_list buffer, matching the approach already used in the DP branch.
Fixes: eff682f83c9c ("drm/amd/display: Add DDC handles for HDCP2.2")
Assisted-by: Copilot:claude-opus-4.6
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c index 0ca39873f807..324413a090bf 100644 --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c @@ -529,7 +529,8 @@ enum mod_hdcp_status mod_hdcp_read_rx_id_list(struct mod_hdcp *hdcp) } else { status = read(hdcp, MOD_HDCP_MESSAGE_ID_READ_REPEATER_AUTH_SEND_RECEIVERID_LIST, hdcp->auth.msg.hdcp2.rx_id_list, - hdcp->auth.msg.hdcp2.rx_id_list_size); + MIN(hdcp->auth.msg.hdcp2.rx_id_list_size, + sizeof(hdcp->auth.msg.hdcp2.rx_id_list))); } return status; } |