[SRU][M][PATCH 0/1] CVE-2024-26591
Bethany Jamison
bethany.jamison at canonical.com
Fri Mar 8 21:15:36 UTC 2024
[Impact]
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix re-attachment branch in bpf_tracing_prog_attach
The following case can cause a crash due to missing attach_btf:
1) load rawtp program
2) load fentry program with rawtp as target_fd
3) create tracing link for fentry program with target_fd = 0
4) repeat 3
In the end we have:
- prog->aux->dst_trampoline == NULL
- tgt_prog == NULL (because we did not provide target_fd to link_create)
- prog->aux->attach_btf == NULL (the program was loaded with
attach_prog_fd=X)
- the program was loaded for tgt_prog but we have no way to find out which
one
BUG: kernel NULL pointer dereference, address: 0000000000000058
Call Trace:
<TASK>
? __die+0x20/0x70
? page_fault_oops+0x15b/0x430
? fixup_exception+0x22/0x330
? exc_page_fault+0x6f/0x170
? asm_exc_page_fault+0x22/0x30
? bpf_tracing_prog_attach+0x279/0x560
? btf_obj_id+0x5/0x10
bpf_tracing_prog_attach+0x439/0x560
__sys_bpf+0x1cf4/0x2de0
__x64_sys_bpf+0x1c/0x30
do_syscall_64+0x41/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
Return -EINVAL in this situation.
[Fix]
Mantic: Clean cherry-pick.
[Test Case]
Compile and boot tested.
[Where problems could occur]
Issues could occur when the user uses bpf, though the risk of regression
is reasonably low as the only change is an additional validation check.
Jiri Olsa (1):
bpf: Fix re-attachment branch in bpf_tracing_prog_attach
kernel/bpf/syscall.c | 9 +++++++++
1 file changed, 9 insertions(+)
--
2.34.1
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