Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum to avoid signed overflow soft lockup sfq_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) (unsigned). A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU 2147483634) makes psched_mtu() return 0x80000000, so slot->allot = INT_MIN and INT_MIN + INT_MIN toggles between INT_MIN and 0 forever, spinning sfq_dequeue() under the qdisc lock. Clamp the quantum to [256, 1 << 20] so the refill loop terminates. The lower bound also covers q->quantum == 0 (psched_mtu() returning 0), which spins sfq_dequeue() identically. sfq_change() already rejects a negative quantum, so only the init path was exposed. Conditions to recreate the bug: a device whose MTU (plus hard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy device with max_mtu == 0 accepting MTU 2147483634). Requires CAP_NET_ADMIN in a user namespace.
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
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 86799499585af06a9431c9e7782658667bd62650affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 2017c355a5a1af77736cd1739fe922f69b5652dcaffected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 6581a82bf08ba5d4e2a6d4e3080df43315b296c4affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 9d782c662879c3adaaca30e05c36910ad11b9e54affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < d72dbdfaeb5b9b8d884e0e036c3442754379ef74affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < aeb8196ecb95146e3410f635628e6cd47352b3e5affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < da16c31517cd2c06bb2c78c73e91ae192c01c426affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 816e90057ab1879562a5b7cc688e35bb9027ae97affected
Linux Linux
Default version status: affected
2.6.12affected0 to < 2.6.12unaffected5.10.270 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/86799499585af06a9431c9e7782658667bd62650 ↗
- https://git.kernel.org/stable/c/2017c355a5a1af77736cd1739fe922f69b5652dc ↗
- https://git.kernel.org/stable/c/6581a82bf08ba5d4e2a6d4e3080df43315b296c4 ↗
- https://git.kernel.org/stable/c/9d782c662879c3adaaca30e05c36910ad11b9e54 ↗
- https://git.kernel.org/stable/c/d72dbdfaeb5b9b8d884e0e036c3442754379ef74 ↗
- https://git.kernel.org/stable/c/aeb8196ecb95146e3410f635628e6cd47352b3e5 ↗
- https://git.kernel.org/stable/c/da16c31517cd2c06bb2c78c73e91ae192c01c426 ↗
- https://git.kernel.org/stable/c/816e90057ab1879562a5b7cc688e35bb9027ae97 ↗