linux-kernel - [PATCHv2 bpf-next 1/4] bpf: Fix uprobe multi pid filter check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240905115124.1503998-2-jolsa@kernel.org>
Date: Thu,  5 Sep 2024 14:51:21 +0300
From: Jiri Olsa <jolsa@...nel.org>
To: Oleg Nesterov <oleg@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Andrii Nakryiko <andrii@...nel.org>,
	Tianyi Liu <i.pear@...look.com>,
	Masami Hiramatsu <mhiramat@...nel.org>
Cc: bpf@...r.kernel.org,
	Steven Rostedt <rostedt@...dmis.org>,
	linux-kernel@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org
Subject: [PATCHv2 bpf-next 1/4] bpf: Fix uprobe multi pid filter check

Uprobe multi link does its own process (thread leader) filtering before
running the bpf program by comparing task's vm pointers.

But as Oleg pointed out there can be processes sharing the vm (CLONE_VM),
so we can't just compare task->vm pointers, but instead we need to use
same_thread_group call.

Suggested-by: Oleg Nesterov <oleg@...hat.com>
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 kernel/trace/bpf_trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b69a39316c0c..98e395f1baae 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3207,7 +3207,7 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe,
 	struct bpf_run_ctx *old_run_ctx;
 	int err = 0;
 
-	if (link->task && current->mm != link->task->mm)
+	if (link->task && !same_thread_group(current, link->task))
 		return 0;
 
 	if (sleepable)
-- 
2.46.0