Description
In the Linux kernel, the following vulnerability has been resolved: media: cec: stm32: prevent out-of-bounds write on RX overflow stm32_rx_done() appends each received CEC byte to rx_msg.msg[] using rx_msg.len as the write index, incrementing it on every RXBR (receive-byte-ready) interrupt without checking it against the buffer size: cec->rx_msg.msg[cec->rx_msg.len++] = val & 0xFF; rx_msg.msg[] is a fixed CEC_MAX_MSG_SIZE (16) byte array in struct cec_msg, and rx_msg.len is only reset on RXACKE/RXOVR or after a completed message (RXEND). The number of bytes received before RXEND is decided by the remote CEC device (it sets EOM), not by the driver. A peer that keeps sending bytes without ending the message drives RXBR repeatedly, pushing rx_msg.len past 16 and writing peer-controlled bytes out of bounds into the surrounding memory. This is reachable in normal operation once the driver has probed and receiving is enabled, from the IRQ thread, without any local privilege. The length check in the CEC core runs on the consumer side, after the byte has been stored, so it does not prevent the overflow. Bound the index in the driver before the store, as the other platform CEC drivers already do (e.g. tegra_cec), dropping the excess bytes of an overlong frame. Found by static analysis tool CodeQL.
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
d69ae57453c80a2193bcdb3fd762efbec447eecf to < f2499b720ea9b874d58770885c6c2e8445a8c3efaffectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < 3df1a4026662121011187247897fe95fd84e8a3aaffectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < 37ac45f7d6e3a6a5dcf6452a0b7bad9a543e8344affectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < 1b4fdefd788db990d1805feb5c7b2388de791ecdaffectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < c3edd7fb8e3692423a702705509947fc9c30b3d1affectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < 0c260d3f97e52978a8c769bb095ac0901333a3acaffectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < a85ce3b175615c2e13bc01e8a1b6b6b6910fde57affectedd69ae57453c80a2193bcdb3fd762efbec447eecf to < fb9dda38d4b9e90db07ed9a0ee2d35bf85494035affected
Linux Linux
Default version status: affected
4.13affected0 to < 4.13unaffected5.10.270 to ≤ 5.10.*unaffected5.15.221 to ≤ 5.15.*unaffected6.1.188 to ≤ 6.1.*unaffected6.6.157 to ≤ 6.6.*unaffected6.12.109 to ≤ 6.12.*unaffected6.18.50 to ≤ 6.18.*unaffected7.2.4 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/f2499b720ea9b874d58770885c6c2e8445a8c3ef ↗
- https://git.kernel.org/stable/c/3df1a4026662121011187247897fe95fd84e8a3a ↗
- https://git.kernel.org/stable/c/37ac45f7d6e3a6a5dcf6452a0b7bad9a543e8344 ↗
- https://git.kernel.org/stable/c/1b4fdefd788db990d1805feb5c7b2388de791ecd ↗
- https://git.kernel.org/stable/c/c3edd7fb8e3692423a702705509947fc9c30b3d1 ↗
- https://git.kernel.org/stable/c/0c260d3f97e52978a8c769bb095ac0901333a3ac ↗
- https://git.kernel.org/stable/c/a85ce3b175615c2e13bc01e8a1b6b6b6910fde57 ↗
- https://git.kernel.org/stable/c/fb9dda38d4b9e90db07ed9a0ee2d35bf85494035 ↗