Description
In the Linux kernel, the following vulnerability has been resolved: drm/bridge: tc358767: clamp the reported AUX read size to the request tc_aux_transfer() clamps an AUX read to the payload limit: size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size); After the transfer it replaces size with the byte count the controller reports in AUX_BYTES: if (size) size = FIELD_GET(AUX_BYTES, auxstatus); AUX_BYTES is GENMASK(15, 8), so it can be up to 255. Nothing clamps it back to the request. tc_aux_read_data() reads that many bytes into the 16-byte auxrdata stack buffer, then copies them into the caller buffer. A reported count of 255 makes the read run to 256 bytes and overruns both. The controller should never report more than it was asked to transfer, so this is defense in depth rather than a live hole. The reported count is only lightly trusted, and the check is cheap. Clamp it back to the request, the same way ti-sn65dsi86 does in commit aca58eac52b8 ("drm/bridge: ti-sn65dsi86: Never store more than msg->size bytes in AUX xfer").
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
12dfe7c4d9c53442efcb4113cff505f60d654906 to < ebf00c51c9ac9188e2806a2b842418805ee879beaffected12dfe7c4d9c53442efcb4113cff505f60d654906 to < 424b762cc26d512e3e7421e57e41b4b55be2400baffected12dfe7c4d9c53442efcb4113cff505f60d654906 to < dd6274706bec30d005bff0587a4262d01dc2775aaffected12dfe7c4d9c53442efcb4113cff505f60d654906 to < 982caa744fce79d18f2920382aaeb0da821a6e73affected12dfe7c4d9c53442efcb4113cff505f60d654906 to < 33c0b072e31dee98a754d9bd01800359dfeb9e8faffected12dfe7c4d9c53442efcb4113cff505f60d654906 to < 57c567e0e8aa76f6e3e8f39d7f40c20bc37e76afaffected12dfe7c4d9c53442efcb4113cff505f60d654906 to < 9ff718df547372d70ca20ad8e66a3fb1300936b2affected12dfe7c4d9c53442efcb4113cff505f60d654906 to < ec6444a00c49e6c2b5e9a507272a28126677f9eeaffected
Linux Linux
Default version status: affected
5.4affected0 to < 5.4unaffected5.10.270 to ≤ 5.10.*unaffected5.15.221 to ≤ 5.15.*unaffected6.1.188 to ≤ 6.1.*unaffected6.6.157 to ≤ 6.6.*unaffected6.12.110 to ≤ 6.12.*unaffected6.18.52 to ≤ 6.18.*unaffected7.2.6 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/ebf00c51c9ac9188e2806a2b842418805ee879be ↗
- https://git.kernel.org/stable/c/424b762cc26d512e3e7421e57e41b4b55be2400b ↗
- https://git.kernel.org/stable/c/dd6274706bec30d005bff0587a4262d01dc2775a ↗
- https://git.kernel.org/stable/c/982caa744fce79d18f2920382aaeb0da821a6e73 ↗
- https://git.kernel.org/stable/c/33c0b072e31dee98a754d9bd01800359dfeb9e8f ↗
- https://git.kernel.org/stable/c/57c567e0e8aa76f6e3e8f39d7f40c20bc37e76af ↗
- https://git.kernel.org/stable/c/9ff718df547372d70ca20ad8e66a3fb1300936b2 ↗
- https://git.kernel.org/stable/c/ec6444a00c49e6c2b5e9a507272a28126677f9ee ↗