CVE-2026-45903

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

bpf: Fix memory access flags in helper prototypes

After commit 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking"),

the verifier started relying on the access type flags in helper

function prototypes to perform memory access optimizations.

Currently, several helper functions utilizing ARG_PTR_TO_MEM lack the

corresponding MEM_RDONLY or MEM_WRITE flags. This omission causes the

verifier to incorrectly assume that the buffer contents are unchanged

across the helper call. Consequently, the verifier may optimize away

subsequent reads based on this wrong assumption, leading to correctness

issues.

For bpf_get_stack_proto_raw_tp, the original MEM_RDONLY was incorrect

since the helper writes to the buffer. Change it to ARG_PTR_TO_UNINIT_MEM

which correctly indicates write access to potentially uninitialized memory.

Similar issues were recently addressed for specific helpers in commit

ac44dcc788b9 ("bpf: Fix verifier assumptions of bpf_d_path's output buffer")

and commit 2eb7648558a7 ("bpf: Specify access type of bpf_sysctl_get_name args").

Fix these prototypes by adding the correct memory access flags.