ethtool: cmis: validate start_cmd_payload_size from module

The CMIS firmware update code reads start_cmd_payload_size from
the module's FW Management Features CDB reply and uses it directly
as the byte count for memcpy. The destination buffer is 112 bytes
(ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH - 8). So a malicious
module (or corrupted response) can cause a OOB write later on in
cmis_fw_update_start_download().

Let's error out. If modules that expect longer LPL writes actually
exist we should revisit.

struct cmis_cdb_start_fw_download_pl's definition has to move,
no change there.

Fixes: c4f78134d4 ("ethtool: cmis_fw_update: add a layer for supporting firmware update using CDB")
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Link: https://patch.msgid.link/20260522231312.1710836-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2026-05-22 16:13:11 -07:00
parent 3e8c3d464c
commit 12c2496a71

View File

@ -44,6 +44,20 @@ enum cmis_cdb_fw_write_mechanism {
CMIS_CDB_FW_WRITE_MECHANISM_BOTH = 0x11,
};
/* See section 9.7.2 "CMD 0101h: Start Firmware Download" in CMIS standard
* revision 5.2.
* struct cmis_cdb_start_fw_download_pl is a structured layout of the
* flat array, ethtool_cmis_cdb_request::payload.
*/
struct cmis_cdb_start_fw_download_pl {
__struct_group(cmis_cdb_start_fw_download_pl_h, head, /* no attrs */,
__be32 image_size;
__be32 resv1;
);
u8 vendor_data[ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH -
sizeof(struct cmis_cdb_start_fw_download_pl_h)];
};
static int
cmis_fw_update_fw_mng_features_get(struct ethtool_cmis_cdb *cdb,
struct net_device *dev,
@ -86,6 +100,14 @@ cmis_fw_update_fw_mng_features_get(struct ethtool_cmis_cdb *cdb,
*/
cdb->read_write_len_ext = rpl->read_write_len_ext;
fw_mng->start_cmd_payload_size = rpl->start_cmd_payload_size;
if (fw_mng->start_cmd_payload_size >
sizeof_field(struct cmis_cdb_start_fw_download_pl, vendor_data)) {
ethnl_module_fw_flash_ntf_err(dev, ntf_params,
"Start cmd payload size exceeds max LPL payload",
NULL);
return -EINVAL;
}
fw_mng->write_mechanism =
rpl->write_mechanism == CMIS_CDB_FW_WRITE_MECHANISM_LPL ?
CMIS_CDB_FW_WRITE_MECHANISM_LPL :
@ -97,20 +119,6 @@ cmis_fw_update_fw_mng_features_get(struct ethtool_cmis_cdb *cdb,
return 0;
}
/* See section 9.7.2 "CMD 0101h: Start Firmware Download" in CMIS standard
* revision 5.2.
* struct cmis_cdb_start_fw_download_pl is a structured layout of the
* flat array, ethtool_cmis_cdb_request::payload.
*/
struct cmis_cdb_start_fw_download_pl {
__struct_group(cmis_cdb_start_fw_download_pl_h, head, /* no attrs */,
__be32 image_size;
__be32 resv1;
);
u8 vendor_data[ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH -
sizeof(struct cmis_cdb_start_fw_download_pl_h)];
};
static int
cmis_fw_update_start_download(struct ethtool_cmis_cdb *cdb,
struct ethtool_cmis_fw_update_params *fw_update,