netdev - [PATCH bpf-next v1 1/2] bpf,ktls: Fix data corruption when using bpf_msg_pop

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: <20250523131915.19349-2-jiayuan.chen@linux.dev>
Date: Fri, 23 May 2025 21:18:58 +0800
From: Jiayuan Chen <jiayuan.chen@...ux.dev>
To: bpf@...r.kernel.org
Cc: Jiayuan Chen <jiayuan.chen@...ux.dev>,
	Cong Wang <xiyou.wangcong@...il.com>,
	Boris Pismenny <borisp@...dia.com>,
	John Fastabend <john.fastabend@...il.com>,
	Jakub Kicinski <kuba@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Andrii Nakryiko <andrii@...nel.org>,
	Eduard Zingerman <eddyz87@...il.com>,
	Mykola Lysenko <mykolal@...com>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Shuah Khan <shuah@...nel.org>,
	Ihor Solodrai <isolodrai@...a.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Subject: [PATCH bpf-next v1 1/2] bpf,ktls: Fix data corruption when using bpf_msg_pop_data() in ktls

When sending plaintext data, we initially calculated the corresponding
ciphertext length. However, if we later reduced the plaintext data length
via socket policy, we failed to recalculate the ciphertext length.

This results in transmitting buffers containing uninitialized data during
ciphertext transmission.

This causes uninitialized bytes to be appended after a complete
"Application Data" packet, leading to errors on the receiving end when
parsing TLS record.

Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling")
Reported-by: Cong Wang <xiyou.wangcong@...il.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@...ux.dev>
---
 net/tls/tls_sw.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index fc88e34b7f33..b23a4655be6a 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -872,6 +872,21 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
 		delta = msg->sg.size;
 		psock->eval = sk_psock_msg_verdict(sk, psock, msg);
 		delta -= msg->sg.size;
+
+		if ((s32)delta > 0) {
+			/* It indicates that we executed bpf_msg_pop_data(),
+			 * causing the plaintext data size to decrease.
+			 * Therefore the encrypted data size also needs to
+			 * correspondingly decrease. We only need to subtract
+			 * delta to calculate the new ciphertext length since
+			 * ktls does not support block encryption.
+			 */
+			if (!WARN_ON_ONCE(!ctx->open_rec)) {
+				struct sk_msg *enc = &ctx->open_rec->msg_encrypted;
+
+				sk_msg_trim(sk, enc, enc->sg.size - delta);
+			}
+		}
 	}
 	if (msg->cork_bytes && msg->cork_bytes > msg->sg.size &&
 	    !enospc && !full_record) {
-- 
2.47.1