CVE-2024-42161: bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELD
First published: Tue Jul 30 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELD [Changes from V1: - Use a default branch in the switch statement to initialize `val'.] GCC warns that `val' may be used uninitialized in the BPF_CRE_READ_BITFIELD macro, defined in bpf_core_read.h as: [...] unsigned long long val; \ [...] \ switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ case 1: val = *(const unsigned char *)p; break; \ case 2: val = *(const unsigned short *)p; break; \ case 4: val = *(const unsigned int *)p; break; \ case 8: val = *(const unsigned long long *)p; break; \ } \ [...] val; \ } \ This patch adds a default entry in the switch statement that sets `val' to zero in order to avoid the warning, and random values to be used in case __builtin_preserve_field_info returns unexpected values for BPF_FIELD_BYTE_SIZE. Tested in bpf-next master. No regressions.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | <5.10.222 | |
| Linux Linux kernel | >=5.11<5.15.163 | |
| Linux Linux kernel | >=5.16<6.1.98 | |
| Linux Linux kernel | >=6.2<6.6.39 | |
| Linux Linux kernel | >=6.7<6.9.9 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.112-1 6.11.9-1 6.11.10-1 |
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Reference Links
- https://git.kernel.org/stable/c/009367099eb61a4fc2af44d4eb06b6b4de7de6db
- https://git.kernel.org/stable/c/3364c2ed1c241989847f19cf83e3db903ce689e3
- https://git.kernel.org/stable/c/7e5471b5efebc30dd0bc035cda86693a5c73d45f
- https://git.kernel.org/stable/c/a21d76bd0b0d39518e9a4c19f6cf7c042a974aff
- https://git.kernel.org/stable/c/b694989bb13ed5f166e633faa1eb0f21c6d261a6
- https://git.kernel.org/stable/c/ff941a8449e712eaf7efca1a13bfb9afd3d99fc2
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-42161
- https://nvd.nist.gov/vuln/detail/CVE-2024-42161
- https://launchpad.net/bugs/cve/CVE-2024-42161
- https://security-tracker.debian.org/tracker/CVE-2024-42161
- https://ubuntu.com/security/CVE-2024-42161
- https://git.kernel.org/linus/009367099eb61a4fc2af44d4eb06b6b4de7de6db
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