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| author | Dave Airlie <airlied@gmail.com> | 2015-10-14 18:51:17 +1000 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2015-10-15 09:06:20 +1000 |
| commit | ae491542cbbbcca0ec8938c37d4079a985e58440 (patch) | |
| tree | e0e7c931aee2edae9b3ce5a9689106557204de8c | |
| parent | bc8c131ccdd62d4ed4f33c6b50f92907e7c32dee (diff) | |
| download | linux-stable-ae491542cbbbcca0ec8938c37d4079a985e58440.tar.gz linux-stable-ae491542cbbbcca0ec8938c37d4079a985e58440.tar.bz2 linux-stable-ae491542cbbbcca0ec8938c37d4079a985e58440.zip | |
drm/dp/mst: make mst i2c transfer code more robust.
This zeroes the msg so no random stack data ends up getting
sent, it also limits the function to not accepting > 4
i2c msgs.
Cc: stable@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 3 | ||||
| -rw-r--r-- | include/drm/drm_dp_mst_helper.h | 3 |
2 files changed, 4 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index bf27a07dbce3..5bca390d9ae2 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2801,12 +2801,13 @@ static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs if (msgs[num - 1].flags & I2C_M_RD) reading = true; - if (!reading) { + if (!reading || (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) { DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n"); ret = -EIO; goto out; } + memset(&msg, 0, sizeof(msg)); msg.req_type = DP_REMOTE_I2C_READ; msg.u.i2c_read.num_transactions = num - 1; msg.u.i2c_read.port_number = port->port_num; diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 0f408b002d98..5340099741ae 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -253,6 +253,7 @@ struct drm_dp_remote_dpcd_write { u8 *bytes; }; +#define DP_REMOTE_I2C_READ_MAX_TRANSACTIONS 4 struct drm_dp_remote_i2c_read { u8 num_transactions; u8 port_number; @@ -262,7 +263,7 @@ struct drm_dp_remote_i2c_read { u8 *bytes; u8 no_stop_bit; u8 i2c_transaction_delay; - } transactions[4]; + } transactions[DP_REMOTE_I2C_READ_MAX_TRANSACTIONS]; u8 read_i2c_device_id; u8 num_bytes_read; }; |