From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72A282BD59C for ; Tue, 1 Sep 2026 11:27:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788262040; cv=none; b=tC1NJp+8flDYnwZC/digrXGtr79TwpgYmZqU2GWdMXC2eMfoBUT3yp0vuowAnZoC9qqQWlcEGfjfCFyMuubNHxABgkMNUMHSwvD4VdM6qoPmUAl4svPb/FPWg5oVrhPFO2zQ8ri/EvFiXj0ax7i+w6GLVIfnuwTCt2D3a7U3ptI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788262040; c=relaxed/simple; bh=r+sUqTRcH0ymeK1uGF2YRrysoiXiQgJXdWJgLMyzioU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t7+loZx8UO4jJnWh9a6NDDJeA+XAuTAr+I4E7rDhDHBWEL356j0GtrSArvjn3xFbxUFwh/lHPYUEANNEwuS0lmYI0Rq+bqXYIpkF5rdVS5aMkbSsZuYafoqLz0VD9ym//M3RU0LdwnQbBHRQGUjf2sltZIkwY4tuCxMVCVvPUs4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UmrORdY4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UmrORdY4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3A1C1F00A3D; Tue, 1 Sep 2026 11:27:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788262039; bh=fovJ7MzybYMUPw4dN/aHKT0kZBlOGVOPiy/yCyaIhAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UmrORdY4CvcI/fp0QHSmPyLVkDtpUWKT8U3ekaDAlqJH5blOTqYJ7/j/VNHhxqCQR p365a9le785kC4zRfRgxZsCcTvAF0PkLn36fsLHKIt8VMqXc/wu5BwfCzvLF6oeOmE 1CO9srX1z0BQLHJZaLBSYYH0tT51VvBFXvkrQJlGQXn0odOSVGUPwMA8Xp2wyTOv4o 7k39lx1RQCAaUbDmdD7ZZV+pX5WVQbR/DYEDJwush5KeWVLq+FQ5IeWBXeCxteQmO/ prpvXMLaJSe9+7CGs+1f2eBi0hR+wkc0T3Qbr9i8ARDvX9SqxGo9Jazi7XNM+O7JWh 7gNFu2b3bQLaA== From: Sasha Levin To: stable@vger.kernel.org Cc: Jiayuan Chen , Paolo Abeni , Sasha Levin Subject: [PATCH 5.15.y] tls: device: fix out-of-bounds write in tls_append_frag() Date: Tue, 1 Sep 2026 07:27:16 -0400 Message-ID: <20260901112716.158417-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026083138-hazily-reword-215c@gregkh> References: <2026083138-hazily-reword-215c@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jiayuan Chen [ Upstream commit b17cf742eaad70ae29ac558cefb3aa9bbeea03d4 ] Found with syzkaller and a local syzbot instance running on top of a netdevsim TLS offload emulation; tls_device.c is otherwise only reachable on a machine with a NIC that implements the offload. tls_push_data() only checks whether the open record still has room for another frag at the bottom of its loop, and the MSG_MORE early break skips that check. The record survives to the next syscall with the frag count it already had, and tls_append_frag() does not check either, so with TLS_TX_ZEROCOPY_RO every splice(SPLICE_F_MORE) of a byte or two adds a non-coalescing pipe page and num_frags walks off the end of tls_record_info.frags[MAX_SKB_FRAGS]. Once the record is pushed, tls_push_record() runs the same index over sg_tx_data[MAX_SKB_FRAGS] and the sg_set_page() writes land on the destruct_work that follows it, which the workqueue then calls. The byte limit is fine because copy drops to 0 and the loop falls through to the same check; the frag count has no such feedback. Push the record rather than keep a full one open, which is what a plain TCP socket does - tcp_sendmsg_locked() uses tcp_mark_push() and new_segment in both the copy and the MSG_SPLICE_PAGES paths, and tls_sw already sets full_record when the sk_msg ring fills up, MSG_MORE or not. BUG: KASAN: slab-out-of-bounds in tls_append_frag ( net/tls/tls_device.c:269) Write of size 8 at addr ffff8881104d1530 by task tls_oob/450 CPU: 2 UID: 0 PID: 450 Comm: tls_oob Not tainted 7.2.0-rc7+ #329 PREEMPT Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) tls_append_frag (net/tls/tls_device.c:269) tls_push_data (net/tls/tls_device.c:518) tls_device_sendmsg (net/tls/tls_device.c:583) inet_sendmsg (net/ipv4/af_inet.c:865) sock_sendmsg (net/socket.c:775 net/socket.c:790 net/socket.c:813) splice_to_socket (fs/splice.c:884) do_splice (fs/splice.c:936 fs/splice.c:1349) __do_splice (fs/splice.c:1431) __x64_sys_splice (fs/splice.c:1634 fs/splice.c:1616) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) and, once the record is pushed: UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:300:24 index 18 is out of range for type 'skb_frag_t [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:301:41 index 18 is out of range for type 'scatterlist [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:302:39 index 18 is out of range for type 'scatterlist [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:307:38 index 26 is out of range for type 'scatterlist [17]' kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffffea000411a680 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation Oops: Oops: 0011 [#1] SMP KASAN PTI Workqueue: ktls_device_destruct 0xffffea000411a680 RIP: 0010:0xffffea000411a680 Call Trace: worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Jiayuan Chen Link: https://patch.msgid.link/20260823084758.20936-1-jiayuan.chen@linux.dev Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/tls/tls_device.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 10f7b35673bc6..2060380265a75 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -493,7 +493,8 @@ static int tls_push_data(struct sock *sk, if (!size) { last_record: tls_push_record_flags = flags; - if (flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE)) { + if ((flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE)) && + record->num_frags < MAX_SKB_FRAGS - 1) { more = true; break; } -- 2.53.0