Cmnt: [SRU][M][PATCH 0/1] CVE-2024-26591

[Magali Lemes]

Yesterday's pull request `[SRU][Mantic][PULL] Mantic upstream stable 
patchset 2024-03-07` already has the fix commit for this CVE.
Unsure if it's worth a NACK though.

On 08/03/2024 18:15, Bethany Jamison wrote:
> [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(+)
>