In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject variable offset alu on PTR_TO_FLOW_KEYS
For PTR_TO_FLOW_KEYS, check_flow_keys_access() only uses fixed off
for validation. However, variable offset ptr alu is not prohibited
for this ptr kind. So the variable offset is not checked.
The following prog is accepted:
func#0 @0
0: R1=ctx() R10=fp0
0: (bf) r6 = r1 ; R1=ctx() R6_w=ctx()
1: (79) r7 = *(u64 *)(r6 +144) ; R6_w=ctx() R7_w=flow_keys()
2: (b7) r8 = 1024 ; R8_w=1024
3: (37) r8 /= 1 ; R8_w=scalar()
4: (57) r8 &= 1024 ; R8_w=scalar(smin=smin32=0,
smax=umax=smax32=umax32=1024,var_off=(0x0; 0x400))
5: (0f) r7 += r8
mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1
mark_precise: frame0: regs=r8 stack= before 4: (57) r8 &= 1024
mark_precise: frame0: regs=r8 stack= before 3: (37) r8 /= 1
mark_precise: frame0: regs=r8 stack= before 2: (b7) r8 = 1024
6: R7_w=flow_keys(smin=smin32=0,smax=umax=smax32=umax32=1024,var_off
=(0x0; 0x400)) R8_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1024,
var_off=(0x0; 0x400))
6: (79) r0 = *(u64 *)(r7 +0) ; R0_w=scalar()
7: (95) exit
This prog loads flow_keys to r7, and adds the variable offset r8
to r7, and finally causes out-of-bounds access:
BUG: unable to handle page fault for address: ffffc90014c80038
[...]
Call Trace:
<TASK>
bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
__bpf_prog_run include/linux/filter.h:651 [inline]
bpf_prog_run include/linux/filter.h:658 [inline]
bpf_prog_run_pin_on_cpu include/linux/filter.h:675 [inline]
bpf_flow_dissect+0x15f/0x350 net/core/flow_dissector.c:991
bpf_prog_test_run_flow_dissector+0x39d/0x620 net/bpf/test_run.c:1359
bpf_prog_test_run kernel/bpf/syscall.c:4107 [inline]
__sys_bpf+0xf8f/0x4560 kernel/bpf/syscall.c:5475
__do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
__x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:5559
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Fix this by rejecting ptr alu with variable offset on flow_keys.
Applying the patch rejects the program with "R7 pointer arithmetic
on flow_keys prohibited".
References
Configurations
Configuration 1 (hide)
|
History
18 Mar 2024, 17:56
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-119 | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| First Time |
Linux linux Kernel
Linux |
|
| References | () https://git.kernel.org/stable/c/1b500d5d6cecf98dd6ca88bc9e7ae1783c83e6d3 - Patch | |
| References | () https://git.kernel.org/stable/c/22c7fa171a02d310e3a3f6ed46a698ca8a0060ed - Patch | |
| References | () https://git.kernel.org/stable/c/29ffa63f21bcdcef3e36b03cccf9d0cd031f6ab0 - Patch | |
| References | () https://git.kernel.org/stable/c/4108b86e324da42f7ed425bd71632fd844300dc8 - Patch | |
| References | () https://git.kernel.org/stable/c/e8d3872b617c21100c5ee4f64e513997a68c2e3d - Patch |
22 Feb 2024, 17:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2024-02-22 17:15
Updated : 2024-03-18 17:56
NVD link : CVE-2024-26589
Mitre link : CVE-2024-26589
CVE.ORG link : CVE-2024-26589
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-119
Improper Restriction of Operations within the Bounds of a Memory Buffer