In the Linux kernel, the following vulnerability has been resolved:
usb: typec: tcpm: Validate SVID index in svdm_consume_modes()
In svdm_consume_modes(), the SVID value is read from pmdata->svids using pmdata->svid_index as an array index without bounds validation:
paltmode->svid = pmdata->svids[pmdata->svid_index];
If pmdata->svid_index is driven beyond SVID_DISCOVERY_MAX (16), it results in an out-of-bounds read of the pmdata->svids array. Because pd_mode_data is embedded inside struct tcpm_port, indexing past svids reads into adjacent fields. In particular:
- At index 16, it reads the altmodes count.
- At index 18 and beyond, it reads into altmode_desc[], which contains partner-supplied SVDM Discovery Modes VDOs.
By injecting a chosen SVID into altmode_desc[0].vdo and driving svid_index to 20, the partner can force paltmode->svid to be loaded with an arbitrary, partner- chosen SVID, which is then registered via typec_partner_register_altmode().
Fix this by validating that pmdata->svid_index is non-negative and strictly less than pmdata->nsvids before accessing the pmdata->svids array inside svdm_consume_modes().
References
- https://git.kernel.org/stable/c/012406f89abc52d1d5f07aa5653b519ebf6d2407
- https://git.kernel.org/stable/c/313ca06e7e224ca1dfadd5722fe71fb8bc276b8b
- https://git.kernel.org/stable/c/3e1b1ac47e8163627f159f30d80d51b914620dd4
- https://git.kernel.org/stable/c/7b681dd5fbf60b24a13c14661e5b7735759fb491
- https://git.kernel.org/stable/c/89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53
- https://git.kernel.org/stable/c/c6d2af3b217a525741c472f0ab45d7d274b8468f
- https://git.kernel.org/stable/c/d638ec188e95fe60f4b01106ffd41958f8fb3c2c
- https://git.kernel.org/stable/c/f8163c414de8640f2ca82ce4dc93409d4cdc2fad