bpf: Fix re-attachment branch in bpf_tracing_prog_attach
commit 715d82ba636cb3629a6e18a33bb9dbe53f9936ee upstream.
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.
BUG=b/330305990
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-26591 in the Linux kernel.
cos-patch: security-moderate
Fixes: f3a95075549e0 ("bpf: Allow trampoline re-attach for tracing and lsm programs")
Cc: [email protected]
Signed-off-by: Jiri Olsa <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Acked-by: Song Liu <[email protected]>
Signed-off-by: Dmitrii Dolgov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Change-Id: If83346f53b2ff3b0e0167f1ed221eb2ac3dcd5ba
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/67791
Reviewed-by: Anil Altinay <[email protected]>
Tested-by: Cusky Presubmit Bot <[email protected]>
1 file changed
