[PATCH AUTOSEL 5.15 09/47] drm/amd/display: Add array index check for hdcp ddc access

Sasha Levin
2024-08-01T00:33:37Z

From: Hersen Wu <hersenxs.wu@amd.com>

[ Upstream commit 4e70c0f5251c25885c31ee84a31f99a01f7cf50e ]

[Why]
Coverity reports OVERRUN warning. Do not check if array
index valid.

[How]
Check msg_id valid and valid array index.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../drm/amd/display/modules/hdcp/hdcp_ddc.c | 28 ++++++++++++++++---
1 file changed, 24 insertions(+), 4 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 8e9caae7c9559..1b2df97226a3f 100644
--- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c
+++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c
@@ -156,11 +156,16 @@ static enum mod_hdcp_status read(struct mod_hdcp *hdcp,
uint32_t cur_size = 0;
uint32_t data_offset = 0;

- if (msg_id == MOD_HDCP_MESSAGE_ID_INVALID) {
+ if (msg_id == MOD_HDCP_MESSAGE_ID_INVALID ||
+ msg_id >= MOD_HDCP_MESSAGE_ID_MAX)
return MOD_HDCP_STATUS_DDC_FAILURE;
- }

if (is_dp_hdcp(hdcp)) {
+ int num_dpcd_addrs = sizeof(hdcp_dpcd_addrs) /
+ sizeof(hdcp_dpcd_addrs[0]);
+ if (msg_id >= num_dpcd_addrs)
+ return MOD_HDCP_STATUS_DDC_FAILURE;
+
while (buf_len > 0) {
cur_size = MIN(buf_len, HDCP_MAX_AUX_TRANSACTION_SIZE);
success = hdcp->config.ddc.funcs.read_dpcd(hdcp->config.ddc.handle,
@@ -175,6 +180,11 @@ static enum mod_hdcp_status read(struct mod_hdcp *hdcp,
data_offset += cur_size;
}
} else {
+ int num_i2c_offsets = sizeof(hdcp_i2c_offsets) /
+ sizeof(hdcp_i2c_offsets[0]);
+ if (msg_id >= num_i2c_offsets)
+ return MOD_HDCP_STATUS_DDC_FAILURE;
+
success = hdcp->config.ddc.funcs.read_i2c(
hdcp->config.ddc.handle,
HDCP_I2C_ADDR,
@@ -219,11 +229,16 @@ static enum mod_hdcp_status write(struct mod_hdcp *hdcp,
uint32_t cur_size = 0;
uint32_t data_offset = 0;

- if (msg_id == MOD_HDCP_MESSAGE_ID_INVALID) {
+ if (msg_id == MOD_HDCP_MESSAGE_ID_INVALID ||
+ msg_id >= MOD_HDCP_MESSAGE_ID_MAX)
return MOD_HDCP_STATUS_DDC_FAILURE;
- }

if (is_dp_hdcp(hdcp)) {
+ int num_dpcd_addrs = sizeof(hdcp_dpcd_addrs) /
+ sizeof(hdcp_dpcd_addrs[0]);
+ if (msg_id >= num_dpcd_addrs)
+ return MOD_HDCP_STATUS_DDC_FAILURE;
+
while (buf_len > 0) {
cur_size = MIN(buf_len, HDCP_MAX_AUX_TRANSACTION_SIZE);
success = hdcp->config.ddc.funcs.write_dpcd(
@@ -239,6 +254,11 @@ static enum mod_hdcp_status write(struct mod_hdcp *hdcp,
data_offset += cur_size;
}
} else {
+ int num_i2c_offsets = sizeof(hdcp_i2c_offsets) /
+ sizeof(hdcp_i2c_offsets[0]);
+ if (msg_id >= num_i2c_offsets)
+ return MOD_HDCP_STATUS_DDC_FAILURE;
+
hdcp->buf[0] = hdcp_i2c_offsets[msg_id];
memmove(&hdcp->buf[1], buf, buf_len);
success = hdcp->config.ddc.funcs.write_i2c(
--
2.43.0