CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
5.1%
In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode
syzbot reported uninit memory usages during map_{lookup,delete}_elem.
The reproducer should be in the interpreter mode.
The C reproducer is trying to run the following bpf prog:
0: (18) r0 = 0x0
2: (18) r1 = map[id:49]
4: (b7) r8 = 16777216
5: (7b) *(u64 *)(r10 -8) = r8
6: (bf) r2 = r10
7: (07) r2 += -229
^^^^^^^^^^
8: (b7) r3 = 8
9: (b7) r4 = 0
10: (85) call dev_map_lookup_elem#1543472
11: (95) exit
It is due to the “void *key” (r2) passed to the helper. bpf allows uninit
stack memory access for bpf prog with the right privileges. This patch
uses kmsan_unpoison_memory() to mark the stack as initialized.
This should address different syzbot reports on the uninit “void *key”
argument during map_{lookup,delete}_elem.
git.kernel.org/stable/c/3189983c26108cf0990e5c46856dc9feb9470d12
git.kernel.org/stable/c/b30f3197a6cd080052d5d4973f9a6b479fd9fff5
git.kernel.org/stable/c/d812ae6e02bd6e6a9cd1fdb09519c2f33e875faf
git.kernel.org/stable/c/e8742081db7d01f980c6161ae1e8a1dbc1e30979
security-tracker.debian.org/tracker/CVE-2024-42063