CVE-2024-49850 Information

Description

In the Linux kernel the following vulnerability has been resolved:

bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos

In case of malformed relocation record of kind BPF_CORE_TYPE_ID_LOCAL referencing a non-existing BTF type function bpf_core_calc_relo_insn would cause a null pointer deference.

Fix this by adding a proper check upper in call stack as malformed relocation records could be passed from user space.

Simplest reproducer is a program:

r0 = 0
exit

With a single relocation record:

.insn_off = 0          / patch first instruction /
.type_id = 100500      / this type id does not exist /
.access_str_off = 6    / offset of string \ /
.kind = BPF_CORE_TYPE_ID_LOCAL

See the link for original reproducer or next commit for a test case.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://git.kernel.org/stable/c/dc7ce14f00bcd50641f2110b7a32aa6552e0780f https://git.kernel.org/stable/c/2288b54b96dcb55bedebcef3572bb8821fc5e708 https://git.kernel.org/stable/c/584cd3ff792e1edbea20b2a7df55897159b0be3e https://git.kernel.org/stable/c/e7e9c5b2dda29067332df2a85b0141a92b41f218 https://git.kernel.org/stable/c/3d2786d65aaa954ebd3fcc033ada433e10da21c4

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5