wired_cmd_repeater_auth_stream_req_in has a variable length array at the end. we use struct_size() overflow macro to determine the size for the allocation and sending size. This also fixes bug in case number of streams is > 0 in the original submission. This bug was not triggered as the number of streams is always one.

Fixes: c56967d674e3 (mei: hdcp: Replace one-element array with flexible-array member) Fixes: 0a1af1b5c18d (misc/mei/hdcp: Verify M_prime) Cc: stable@vger.kernel.org # v5.1+: c56967d674e3 (mei: hdcp: Replace one-element array with flexible-array member) Signed-off-by: Tomas Winkler tomas.winkler@intel.com Reviewed-by: Gustavo A. R. Silva gustavoars@kernel.org --- V5: 1. Add reference to depending patch for stable V4: 1. Fix typo in the subject. (Gustavo) 2. Fix dereferencing pointer in send. (Gustavo) V3: 1. Fix commit message with more info and another patch it fixes (Gustavo) 2. Target stable. (Gustavo) V2: 1. Check for allocation failure.

drivers/misc/mei/hdcp/mei_hdcp.c | 40 +++++++++++++++++++------------- 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c index d1d3e025ca0e..9ae9669e46ea 100644 --- a/drivers/misc/mei/hdcp/mei_hdcp.c +++ b/drivers/misc/mei/hdcp/mei_hdcp.c @@ -546,38 +546,46 @@ static int mei_hdcp_verify_mprime(struct device *dev, struct hdcp_port_data *data, struct hdcp2_rep_stream_ready *stream_ready) { - struct wired_cmd_repeater_auth_stream_req_in - verify_mprime_in = { { 0 } }; + struct wired_cmd_repeater_auth_stream_req_in *verify_mprime_in; struct wired_cmd_repeater_auth_stream_req_out verify_mprime_out = { { 0 } }; struct mei_cl_device *cldev; ssize_t byte; + size_t cmd_size;

if (!dev || !stream_ready || !data) return -EINVAL;

cldev = to_mei_cl_device(dev);

- verify_mprime_in.header.api_version = HDCP_API_VERSION; - verify_mprime_in.header.command_id = WIRED_REPEATER_AUTH_STREAM_REQ; - verify_mprime_in.header.status = ME_HDCP_STATUS_SUCCESS; - verify_mprime_in.header.buffer_len = + cmd_size = struct_size(verify_mprime_in, streams, data->k); + if (cmd_size == SIZE_MAX) + return -EINVAL; + + verify_mprime_in = kzalloc(cmd_size, GFP_KERNEL); + if (!verify_mprime_in) + return -ENOMEM; + + verify_mprime_in->header.api_version = HDCP_API_VERSION; + verify_mprime_in->header.command_id = WIRED_REPEATER_AUTH_STREAM_REQ; + verify_mprime_in->header.status = ME_HDCP_STATUS_SUCCESS; + verify_mprime_in->header.buffer_len = WIRED_CMD_BUF_LEN_REPEATER_AUTH_STREAM_REQ_MIN_IN;

- verify_mprime_in.port.integrated_port_type = data->port_type; - verify_mprime_in.port.physical_port = (u8)data->fw_ddi; - verify_mprime_in.port.attached_transcoder = (u8)data->fw_tc; + verify_mprime_in->port.integrated_port_type = data->port_type; + verify_mprime_in->port.physical_port = (u8)data->fw_ddi; + verify_mprime_in->port.attached_transcoder = (u8)data->fw_tc; + + memcpy(verify_mprime_in->m_prime, stream_ready->m_prime, HDCP_2_2_MPRIME_LEN); + drm_hdcp_cpu_to_be24(verify_mprime_in->seq_num_m, data->seq_num_m);

- memcpy(verify_mprime_in.m_prime, stream_ready->m_prime, - HDCP_2_2_MPRIME_LEN); - drm_hdcp_cpu_to_be24(verify_mprime_in.seq_num_m, data->seq_num_m); - memcpy(verify_mprime_in.streams, data->streams, + memcpy(verify_mprime_in->streams, data->streams, array_size(data->k, sizeof(*data->streams)));

- verify_mprime_in.k = cpu_to_be16(data->k); + verify_mprime_in->k = cpu_to_be16(data->k);

- byte = mei_cldev_send(cldev, (u8 *)&verify_mprime_in, - sizeof(verify_mprime_in)); + byte = mei_cldev_send(cldev, (u8 *)verify_mprime_in, cmd_size); + kfree(verify_mprime_in); if (byte < 0) { dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte); return byte;