Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN The BPF interpreter's signed 32-bit division and modulo handlers use the kernel abs() macro on s32 operands. The abs() macro documentation (include/linux/math.h) explicitly states the result is undefined when the input is the type minimum. When DST contains S32_MIN (0x80000000), abs((s32)DST) triggers undefined behavior and returns S32_MIN unchanged on arm64/x86. This value is then sign-extended to u64 as 0xFFFFFFFF80000000, causing do_div() to compute the wrong result. The verifier's abstract interpretation (scalar32_min_max_sdiv) computes the mathematically correct result for range tracking, creating a verifier/interpreter mismatch that can be exploited for out-of-bounds map value access. Introduce abs_s32() which handles S32_MIN correctly by casting to u32 before negating, avoiding signed overflow entirely. Replace all 8 abs((s32)...) call sites in the interpreter's sdiv32/smod32 handlers. s32 is the only affected case -- the s64 division/modulo handlers do not use abs().
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 before 694ea55f1b1c74f9942d91ec366ae9e822422e42; affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 before 9ab1227765c446942f290c83382f0b19887c55cf; affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 before f14ca604c0ff274fba19f73f1f0485c0047c1396; affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 before 0d5d8c3ce45c734aaf3c51cbef59155a6746157d; affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 before c77b30bd1dcb61f66c640ff7d2757816210c7cb0 |
| Linux / Linux | affected 6.6; unaffected 0 before 6.6; unaffected 6.6.131 through 6.6.*; unaffected 6.12.80 through 6.12.*; unaffected 6.18.21 through 6.18.*; unaffected 6.19.11 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/694ea55f1b1c74f9942d91ec366ae9e822422e42
- https://git.kernel.org/stable/c/9ab1227765c446942f290c83382f0b19887c55cf
- https://git.kernel.org/stable/c/f14ca604c0ff274fba19f73f1f0485c0047c1396
- https://git.kernel.org/stable/c/0d5d8c3ce45c734aaf3c51cbef59155a6746157d
- https://git.kernel.org/stable/c/c77b30bd1dcb61f66c640ff7d2757816210c7cb0
ADP enrichment
No English description supplied.
No references supplied.