Commit 45d08c1d authored by Jiri Olsa's avatar Jiri Olsa Committed by Pu Lehui
Browse files

bpf,perf: Fix invalid prog_array access in perf_event_detach_bpf_prog 

stable inclusion
from stable-v6.6.67
commit c2b6b47662d5f2dfce92e5ffbdcac8229f321d9d
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBEAN1
CVE: CVE-2024-56665

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c2b6b47662d5

--------------------------------

commit 978c4486cca5c7b9253d3ab98a88c8e769cb9bbd upstream.

Syzbot reported [1] crash that happens for following tracing scenario:

  - create tracepoint perf event with attr.inherit=1, attach it to the
    process and set bpf program to it
  - attached process forks -> chid creates inherited event

    the new child event shares the parent's bpf program and tp_event
    (hence prog_array) which is global for tracepoint

  - exit both process and its child -> release both events
  - first perf_event_detach_bpf_prog call will release tp_event->prog_array
    and second perf_event_detach_bpf_prog will crash, because
    tp_event->prog_array is NULL

The fix makes sure the perf_event_detach_bpf_prog checks prog_array
is valid before it tries to remove the bpf program from it.

[1] https://lore.kernel.org/bpf/Z1MR6dCIKajNS6nU@krava/T/#m91dbf0688221ec7a7fc95e896a7ef9ff93b0b8ad



Fixes: 0ee288e69d03 ("bpf,perf: Fix perf_event_detach_bpf_prog error handling")
Reported-by: default avatar <syzbot+2e0d2840414ce817aaac@syzkaller.appspotmail.com>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241208142507.1207698-1-jolsa@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarPu Lehui <pulehui@huawei.com>
parent c2f1662c

kernel/trace/bpf_trace.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -2216,6 +2216,9 @@ void perf_event_detach_bpf_prog(struct perf_event *event) 
		goto unlock;

		goto unlock;





	old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);

	old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);

	if (!old_array)

		goto put;



	ret = bpf_prog_array_copy(old_array, event->prog, NULL, 0, &new_array);

	ret = bpf_prog_array_copy(old_array, event->prog, NULL, 0, &new_array);

	if (ret < 0) {

	if (ret < 0) {

		bpf_prog_array_delete_safe(old_array, event->prog);

		bpf_prog_array_delete_safe(old_array, event->prog);
@@ -2224,6 +2227,7 @@ void perf_event_detach_bpf_prog(struct perf_event *event) 
		bpf_prog_array_free_sleepable(old_array);

		bpf_prog_array_free_sleepable(old_array);

	}

	}





put:

	/*

	/*

	 * It could be that the bpf_prog is not sleepable (and will be freed

	 * It could be that the bpf_prog is not sleepable (and will be freed

	 * via normal RCU), but is called from a point that supports sleepable

	 * via normal RCU), but is called from a point that supports sleepable