xsk: Use a 32-bit compare in xsk_map_gen_lookup

Overview

In the Linux kernel, the following vulnerability has been resolved:

xsk: Use a 32-bit compare in xsk_map_gen_lookup

xsk_map_gen_lookup() loads a u32 key and compares it with max_entries using BPF_JMP_IMM. BPF immediates are sign-extended to 64 bits, so a max_entries value of 0x80000000 or higher becomes a threshold larger than every zero-extended 32-bit key. An out-of-range index then skips the bounds check and the generated lookup reads past xsk_map[].

Compare with BPF_JMP32_IMM so the check stays in 32-bit unsigned range.

Affected

• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < c6d5c582d55a8f229d75e98d62eaa065b0deb18d
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < 227ec890559e922e235eb543646e3bf0bd8269b0
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < 11d9be35c1f4233798e99be98bc474f83a254c6c
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < 123f90f394ca404ab8796a7c8072ff7fa5b65a9c
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < 36461e58f88a1b723f86693f437ac12e60ff4363
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < b5c0cff0c5331582ab01c4c423731453a8381acc
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < 3c1e0a4bc156b8d5c5772dbc76b9ea74dce5ca24
• Linux >= e65650f291ee72fc578d6346080fc4699204ef2c < 70504de0bb627848667207bec7ccfd647deb8814
• Linux 5.5

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.