netdev - [PATCH AUTOSEL 5.4 64/74] media, bpf: Do not copy more entries than user space requested

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>] [day] [month] [year] [list]

Message-Id: <20210706112502.2064236-64-sashal@kernel.org>
Date:   Tue,  6 Jul 2021 07:24:52 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Sean Young <sean@...s.org>, Daniel Borkmann <daniel@...earbox.net>,
        Sasha Levin <sashal@...nel.org>, linux-media@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 64/74] media, bpf: Do not copy more entries than user space requested

From: Sean Young <sean@...s.org>

[ Upstream commit 647d446d66e493d23ca1047fa8492b0269674530 ]

The syscall bpf(BPF_PROG_QUERY, &attr) should use the prog_cnt field to
see how many entries user space provided and return ENOSPC if there are
more programs than that. Before this patch, this is not checked and
ENOSPC is never returned.

Note that one lirc device is limited to 64 bpf programs, and user space
I'm aware of -- ir-keytable -- always gives enough space for 64 entries
already. However, we should not copy program ids than are requested.

Signed-off-by: Sean Young <sean@...s.org>
Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Link: https://lore.kernel.org/bpf/20210623213754.632-1-sean@mess.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/rc/bpf-lirc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c
index 0a0ce620e4a2..d5f839fdcde7 100644
--- a/drivers/media/rc/bpf-lirc.c
+++ b/drivers/media/rc/bpf-lirc.c
@@ -329,7 +329,8 @@ int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
 	}
 
 	if (attr->query.prog_cnt != 0 && prog_ids && cnt)
-		ret = bpf_prog_array_copy_to_user(progs, prog_ids, cnt);
+		ret = bpf_prog_array_copy_to_user(progs, prog_ids,
+						  attr->query.prog_cnt);
 
 unlock:
 	mutex_unlock(&ir_raw_handler_lock);
-- 
2.30.2