linux-kernel - [PATCH bpf-next v9 2/3] bpf: clean-up bounds checking in __bpf_get

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: <20250912233509.74996-1-contact@arnaud-lcm.com>
Date: Sat, 13 Sep 2025 00:35:09 +0100
From: Arnaud Lecomte <contact@...aud-lcm.com>
To: alexei.starovoitov@...il.com,
	yonghong.song@...ux.dev,
	song@...nel.org
Cc: andrii@...nel.org,
	ast@...nel.org,
	bpf@...r.kernel.org,
	daniel@...earbox.net,
	eddyz87@...il.com,
	haoluo@...gle.com,
	john.fastabend@...il.com,
	jolsa@...nel.org,
	kpsingh@...nel.org,
	linux-kernel@...r.kernel.org,
	martin.lau@...ux.dev,
	sdf@...ichev.me,
	syzbot+c9b724fbb41cf2538b7b@...kaller.appspotmail.com,
	syzkaller-bugs@...glegroups.com,
	contact@...aud-lcm.com
Subject: [PATCH bpf-next v9 2/3] bpf: clean-up bounds checking in
 __bpf_get_stack

Clean-up bounds checking for trace->nr in
__bpf_get_stack by limiting it only to
max_depth.

Acked-by: Song Liu <song@...nel.org>
Cc: Song Liu <song@...nel.org>
Signed-off-by: Arnaud Lecomte <contact@...aud-lcm.com>
---
 kernel/bpf/stackmap.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index a794e04f5ae9..9a86b5acac10 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -462,13 +462,15 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task,
 	if (may_fault)
 		rcu_read_lock(); /* need RCU for perf's callchain below */
 
-	if (trace_in)
+	if (trace_in) {
 		trace = trace_in;
-	else if (kernel && task)
+		trace->nr = min_t(u32, trace->nr, max_depth);
+	} else if (kernel && task) {
 		trace = get_callchain_entry_for_task(task, max_depth);
-	else
+	} else {
 		trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
 					   crosstask, false);
+	}
 
 	if (unlikely(!trace) || trace->nr < skip) {
 		if (may_fault)
-- 
2.43.0