Oracle Linux: CVE-2024-42161: ELSA-2024-12618: Unbreakable Enterprise kernel security update (IMPORTANT)

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.
A vulnerability was found in the Linux kernel in the bpf_enum_value_kind() function, where a lack of proper checks could lead to an uninitialized variable being used. This issue could lead to undefined behavior or memory corruption.