Description

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

bpf: Fix a sdiv overflow issue

Zac Ecob reported a problem where a bpf program may cause kernel crash due
to the following error:
Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI

The failure is due to the below signed divide:
LLONG_MIN/-1 where LLONG_MIN equals to -9,223,372,036,854,775,808.
LLONG_MIN/-1 is supposed to give a positive number 9,223,372,036,854,775,808,
but it is impossible since for 64-bit system, the maximum positive
number is 9,223,372,036,854,775,807. On x86_64, LLONG_MIN/-1 will
cause a kernel exception. On arm64, the result for LLONG_MIN/-1 is
LLONG_MIN.

Further investigation found all the following sdiv/smod cases may trigger
an exception when bpf program is running on x86_64 platform:
- LLONG_MIN/-1 for 64bit operation
- INT_MIN/-1 for 32bit operation
- LLONG_MIN%-1 for 64bit operation
- INT_MIN%-1 for 32bit operation
where -1 can be an immediate or in a register.

On arm64, there are no exceptions:
- LLONG_MIN/-1 = LLONG_MIN
- INT_MIN/-1 = INT_MIN
- LLONG_MIN%-1 = 0
- INT_MIN%-1 = 0
where -1 can be an immediate or in a register.

Insn patching is needed to handle the above cases and the patched codes
produced results aligned with above arm64 result. The below are pseudo
codes to handle sdiv/smod exceptions including both divisor -1 and divisor 0
and the divisor is stored in a register.

sdiv:
tmp = rX
tmp += 1 /* [-1, 0] -> [0, 1]
if tmp ...

Classification

CVE ID: CVE-2024-49888

CVSS Base Severity: MEDIUM

CVSS Base Score: 5.5

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 5.52% (scored less or equal to compared to others)

EPSS Date: 2025-06-02 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2024-49888
https://git.kernel.org/stable/c/4902a6a0dc593c82055fc8c9ada371bafe26c9cc
https://git.kernel.org/stable/c/d22e45a369afc7c28f11acfa5b5e8e478227ca5d
https://git.kernel.org/stable/c/7dd34d7b7dcf9309fc6224caf4dd5b35bedddcb7

Timeline