Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX modes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX]. But the CMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming ACK with any request the port actually sent. Once port->partner is set, an unsolicited Discover Modes ACK is consumed unconditionally. A broken or malicious port partner can therefore drive altmodes to ALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra Discover Modes ACK with seven VDOs. Because the pre-loop check passes, the loop could then writes up to five entries past altmode_desc[]. For mode_data_prime the next field in struct tcpm_port is the partner_altmode[] pointer array, which then receives partner-chosen SVID/VDO bytes. Move the bound check inside the loop so the array can never be indexed past ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner supplies or how the function was reached.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 4ab8c18d4d67321cc7b660559de17511d4fc0237 before 816c6251409db28f1b875988fcbd2ff1764a81f0; affected 4ab8c18d4d67321cc7b660559de17511d4fc0237 before 845598b154b9a92e9d279fafafa9405c121ae805; affected 4ab8c18d4d67321cc7b660559de17511d4fc0237 before 4505f33dab56c274e82f47f94bf60a8cbf8f4b42; affected 4ab8c18d4d67321cc7b660559de17511d4fc0237 before cbad85b446c06adbc5e5bed565871bb918ce9d32; affected 4ab8c18d4d67321cc7b660559de17511d4fc0237 before 3389c149c68c3fea61910ad5d34f7bf3bff44e32 |
| Linux / Linux | affected 4.19; unaffected 0 before 4.19; unaffected 6.6.160 through 6.6.*; unaffected 6.12.93 through 6.12.*; unaffected 6.18.35 through 6.18.*; unaffected 7.0.12 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/816c6251409db28f1b875988fcbd2ff1764a81f0
- https://git.kernel.org/stable/c/845598b154b9a92e9d279fafafa9405c121ae805
- https://git.kernel.org/stable/c/4505f33dab56c274e82f47f94bf60a8cbf8f4b42
- https://git.kernel.org/stable/c/cbad85b446c06adbc5e5bed565871bb918ce9d32
- https://git.kernel.org/stable/c/3389c149c68c3fea61910ad5d34f7bf3bff44e32