Huawei EulerOS: CVE-2024-49861: kernel security update

Huawei EulerOS: CVE-2024-49861: kernel security update

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

10/21/2024

Created

02/12/2025

Added

02/11/2025

Modified

02/11/2025

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix helper writes to read-only maps Lonial found an issue that despite user- and BPF-side frozen BPF map (like in case of .rodata), it was still possible to write into it from a BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT} as arguments. In check_func_arg() when the argument is as mentioned, the meta->raw_mode is never set. Later, check_helper_mem_access(), under the case of PTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the subsequent call to check_map_access_type() and given the BPF map is read-only it succeeds. The helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT when results are written into them as opposed to read out of them. The latter indicates that it's okay to pass a pointer to uninitialized memory as the memory is written to anyway. However, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM just with additional alignment requirement. So it is better to just get rid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the fixed size memory types. For this, add MEM_ALIGNED to additionally ensure alignment given these helpers write directly into the args via *<ptr> = val. The .arg*_size has been initialized reflecting the actual sizeof(*<ptr>). MEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated argument types, since in !MEM_FIXED_SIZE cases the verifier does not know the buffer size a priori and therefore cannot blindly write *<ptr> = val.

Solution(s)

• huawei-euleros-2_0_sp11-upgrade-bpftool
• huawei-euleros-2_0_sp11-upgrade-kernel
• huawei-euleros-2_0_sp11-upgrade-kernel-abi-stablelists
• huawei-euleros-2_0_sp11-upgrade-kernel-tools
• huawei-euleros-2_0_sp11-upgrade-kernel-tools-libs
• huawei-euleros-2_0_sp11-upgrade-python3-perf

References

• https://attackerkb.com/topics/cve-2024-49861
• CVE - 2024-49861
• EulerOS-SA-2025-1159