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medium6.3

CVE-2024-42161

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 …

Impact

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.

Affected products

VendorProductAffected versions
LinuxLinux Kernel
before 5.10.222
from 5.11 before 5.15.163
from 5.16 before 6.1.98
from 6.2 before 6.6.39
from 6.7 before 6.9.9

Weakness classification

CWE-908

References