From: Lee Jones <lee@kernel.org>
To: lee@kernel.org
Cc: linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
bpf@vger.kernel.org
Subject: [PATCH v3 1/1] bpf: Ensure correct locking around vulnerable function find_vpid()
Date: Mon, 12 Sep 2022 14:38:55 +0100 [thread overview]
Message-ID: <20220912133855.1218900-1-lee@kernel.org> (raw)
The documentation for find_vpid() clearly states:
"Must be called with the tasklist_lock or rcu_read_lock() held."
Presently we do neither.
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: bpf@vger.kernel.org
Fixes: 41bdc4b40ed6f ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
Signed-off-by: Lee Jones <lee@kernel.org>
---
v2 => v3:
* Changed strategy from find_get_pid() to rcu_read_{un}lock()
* Removed Jiri's Ack
v1 => v2:
* Commit log update - no code differences
kernel/bpf/syscall.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 69be1c612daa5..d5c77c021c043 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4399,7 +4399,9 @@ static int bpf_task_fd_query(const union bpf_attr *attr,
if (attr->task_fd_query.flags != 0)
return -EINVAL;
+ rcu_read_lock();
task = get_pid_task(find_vpid(pid), PIDTYPE_PID);
+ rcu_read_unlock();
if (!task)
return -ENOENT;
--
2.37.2.789.g6183377224-goog
next reply other threads:[~2022-09-12 13:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 13:38 Lee Jones [this message]
2022-09-12 14:55 ` [PATCH v3 1/1] bpf: Ensure correct locking around vulnerable function find_vpid() Yonghong Song
2022-09-12 15:14 ` Lee Jones
2022-09-12 16:02 ` Yonghong Song
2022-09-16 16:10 ` patchwork-bot+netdevbpf
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