platform/chrome: cros_ec_typec: Validate SVID and mode counts in discovery data

cros_typec_register_altmodes() iterates over sop_disc->svid_count and
sop_disc->svids[i].mode_count from the EC_CMD_TYPEC_DISCOVERY response
without validating their bounds.

port->disc_data is allocated as a buffer of EC_PROTO2_MAX_RESPONSE_SIZE
bytes, and each SVID entry contains a fixed mode_vdo[6] array. If the EC
returns an out-of-bounds svid_count or mode_count, the loops read past
the end of the mode_vdo array or the disc_data buffer.

Validate that the discovery response with svid_count entries fits within
EC_PROTO2_MAX_RESPONSE_SIZE using struct_size(), and ensure each SVID's
mode_count does not exceed ARRAY_SIZE(sop_disc->svids[i].mode_vdo)
before registering altmodes.

Fixes: de0f49487db3 ("platform/chrome: cros_ec_typec: Register partner altmodes")
Signed-off-by: Bartosz Szpila <bszpila@google.com>
Reviewed-by: Andrei Kuchynski <akuchynski@chromium.org>
Link: https://lore.kernel.org/r/20261001085714.1086242-1-bszpila@google.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

0 files changed, 0 insertions, 0 deletions