From: Jann Horn <jannh@google.com> stable inclusion from stable-v6.6.67 commit f9f85df30118f3f4112761e6682fc60ebcce23e5 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBEAKR CVE: CVE-2024-56675 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit ef1b808e3b7c98612feceedf985c2fbbeb28f956 upstream. Uprobes always use bpf_prog_run_array_uprobe() under tasks-trace-RCU protection. But it is possible to attach a non-sleepable BPF program to a uprobe, and non-sleepable BPF programs are freed via normal RCU (see __bpf_prog_put_noref()). This leads to UAF of the bpf_prog because a normal RCU grace period does not imply a tasks-trace-RCU grace period. Fix it by explicitly waiting for a tasks-trace-RCU grace period after removing the attachment of a bpf_prog to a perf_event. Fixes: 8c7dcb84e3b7 ("bpf: implement sleepable uprobes by chaining gps") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/bpf/20241210-bpf-fix-actual-uprobe-uaf-v1-1-19439849... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Pu Lehui <pulehui@huawei.com> --- kernel/trace/bpf_trace.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 93e06d370395..b084fe1dbe12 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2224,6 +2224,13 @@ void perf_event_detach_bpf_prog(struct perf_event *event) bpf_prog_array_free_sleepable(old_array); } + /* + * 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 + * programs and uses tasks-trace-RCU. + */ + synchronize_rcu_tasks_trace(); + bpf_prog_put(event->prog); event->prog = NULL; -- 2.34.1