Description

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

netfilter: nf_conntrack_h323: Add protection for bmp length out of range

UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts
that are out of bounds for their data type.

vmlinux get_bitmap(b=75) + 712

vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956

vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216

vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812

vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216

vmlinux DecodeRasMessage() + 304

vmlinux ras_help() + 684

vmlinux nf_confirm() + 188

Due to abnormal data in skb->data, the extension bitmap length
exceeds 32 when decoding ras message then uses the length to make
a shift operation. It will change into negative after several loop.
UBSAN load could detect a negative shift as an undefined behaviour
and reports exception.
So we add the protection to avoid the length exceeding 32. Or else
it will return out of range error and stop decoding.

Classification

CVE ID: CVE-2024-26851

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/98db42191329c679f4ca52bec0b319689e1ad8cb
https://git.kernel.org/stable/c/4bafcc43baf7bcf93566394dbd15726b5b456b7a
https://git.kernel.org/stable/c/ccd1108b16ab572d9bf635586b0925635dbd6bbc
https://git.kernel.org/stable/c/b3c0f553820516ad4b62a9390ecd28d6f73a7b13
https://git.kernel.org/stable/c/39001e3c42000e7c2038717af0d33c32319ad591
https://git.kernel.org/stable/c/014a807f1cc9c9d5173c1cd935835553b00d211c
https://git.kernel.org/stable/c/80ee5054435a11c87c9a4f30f1ff750080c96416
https://git.kernel.org/stable/c/767146637efc528b5e3d31297df115e85a2fd362

Timeline