From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f74.google.com (mail-qv1-f74.google.com [209.85.219.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7FEF12D78A for ; Thu, 18 Jan 2024 18:36:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705602989; cv=none; b=gCu5nxKpCkdLt0jhec/ONjUimwqdxgxfRPvRrceH+CWhShebpXPKEHCFTKZJu2FMqrmHB+qBal+J3w+5CTA1zuQjR2KGqVBCsQCBZ+RM5cWNL3AN85LoQh2LOFcZjO1oykx1Pnx1LSIDwp7hJyMByiAhNlV7fuyiYfMWH0EctSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705602989; c=relaxed/simple; bh=RFNfwEsJvbylNgRnN6/aIObtRSNXMPythkZb7onAXks=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=k9uhX45bJi3p/UAq7dpzUMoRJMMwDSdovhz5xC1qJClyA37/66SLTIZd17G7hgVt/WZoZMWTZ3t1v2qVGHb9fmWCoPxeTiltGvHCfSV+V60sHjx5HWb3y7mF4fibwgaN3C5Glf0LYej2/7E1xy/Pu66CA2GmkmDlReYHgyKypeg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=hEIPhW93; arc=none smtp.client-ip=209.85.219.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hEIPhW93" Received: by mail-qv1-f74.google.com with SMTP id 6a1803df08f44-681684ca881so48062236d6.2 for ; Thu, 18 Jan 2024 10:36:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1705602986; x=1706207786; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=25MdXHON6j2NwO0BaoY9TcGqu9Z4Ggpqr593eNpu2a4=; b=hEIPhW93ANVJTJRvx1upgxGFSejHPebgSU2tR8Z8zTBM6GiNaQCF3VZo27nWlbUxeW FNk3/hYKi9VEpX1ev1s2VOjLsRk6M8SOFoP1kSSEZfnUDlS9OfboHhszBtHJ0Nvar3+a x4SRcKshs1RLMMEgj5kMGs1kQiT20/xIib+WRPp0CaRBvFo9Lf0dB5hbNhRrlANTNb2N PtS2vJA/GysbiaK4W/GQsbJDOHtHcZq2i6m271B2Cq+7rcdsuuNY6n4Wh3FjUnwPKhmF zsM6sawPTX/nzZzmyhF2jnRd2lPymA6350tMAUlcSMuMae3WQ0HeoOOWazptlpSTlleo 59HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705602986; x=1706207786; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=25MdXHON6j2NwO0BaoY9TcGqu9Z4Ggpqr593eNpu2a4=; b=lvzJm9VXofM4WmWhiy69EJYMzVSOE6UZCqhSBHcAZzd9tCIyRU+fCy+dA8ts/0kTG4 jeVXU7F+SLVSojxibt+sEahXzyuqRLN8nSt3yi9voU7OMtmpk7r7z2CA7DcAVNWMn+jH cf3K/ZqCSScAomK2E7cultfehhQTflJSsbmm6y/YIrqrgB4w6zBlyOnmho3EiPrPzqYG y8IeOdUeK31uS2xdro7oaXfySmm0bU9bOyU+S4d3YkqEepuG4u4gCMnFZHiGfxDXbHBh nbi5V4G4TAm+TygVGTIok/KY1V8aS9j8ERLQdGxfGfKwB/TGg7UsL+lmYvISYXx/dRLD pVzA== X-Gm-Message-State: AOJu0YxnLUn6VMVPK/yaJ6ySIvPOKAEOUctg2rmmxub9epaeizeS500B D7pjRoiCoUDC8Eb/aDfHN5WYWaY2Ad4Vd1lVrDK3au6EVQi1rdEoGETnxcwmApHG74jycrNfmJD vU5i4m3eyIQ== X-Google-Smtp-Source: AGHT+IHh19cnk/darzEc3E39WxuE9OKGoS2V+Tv0rxm+SKD0cyLn2NzdCib+4iqypfExJeN1FcqO1dIpJNtypQ== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a05:6214:1042:b0:681:7c2b:2791 with SMTP id l2-20020a056214104200b006817c2b2791mr28269qvr.12.1705602986549; Thu, 18 Jan 2024 10:36:26 -0800 (PST) Date: Thu, 18 Jan 2024 18:36:25 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.43.0.429.g432eaa2c6b-goog Message-ID: <20240118183625.4007013-1-edumazet@google.com> Subject: [PATCH net] llc: make llc_ui_sendmsg() more robust against bonding changes From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , syzbot+2a7024e9502df538e8ef@syzkaller.appspotmail.com Content-Type: text/plain; charset="UTF-8" syzbot was able to trick llc_ui_sendmsg(), allocating an skb with no headroom, but subsequently trying to push 14 bytes of Ethernet header [1] Like some others, llc_ui_sendmsg() releases the socket lock before calling sock_alloc_send_skb(). Then it acquires it again, but does not redo all the sanity checks that were performed. This fix: - Uses LL_RESERVED_SPACE() to reserve space. - Check all conditions again after socket lock is held again. - Do not account Ethernet header for mtu limitation. [1] skbuff: skb_under_panic: text:ffff800088baa334 len:1514 put:14 head:ffff0000c9c37000 data:ffff0000c9c36ff2 tail:0x5dc end:0x6c0 dev:bond0 kernel BUG at net/core/skbuff.c:193 ! Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 6875 Comm: syz-executor.0 Not tainted 6.7.0-rc8-syzkaller-00101-g0802e17d9aca-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : skb_panic net/core/skbuff.c:189 [inline] pc : skb_under_panic+0x13c/0x140 net/core/skbuff.c:203 lr : skb_panic net/core/skbuff.c:189 [inline] lr : skb_under_panic+0x13c/0x140 net/core/skbuff.c:203 sp : ffff800096f97000 x29: ffff800096f97010 x28: ffff80008cc8d668 x27: dfff800000000000 x26: ffff0000cb970c90 x25: 00000000000005dc x24: ffff0000c9c36ff2 x23: ffff0000c9c37000 x22: 00000000000005ea x21: 00000000000006c0 x20: 000000000000000e x19: ffff800088baa334 x18: 1fffe000368261ce x17: ffff80008e4ed000 x16: ffff80008a8310f8 x15: 0000000000000001 x14: 1ffff00012df2d58 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000001 x10: 0000000000ff0100 x9 : e28a51f1087e8400 x8 : e28a51f1087e8400 x7 : ffff80008028f8d0 x6 : 0000000000000000 x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff800082b78714 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000089 Call trace: skb_panic net/core/skbuff.c:189 [inline] skb_under_panic+0x13c/0x140 net/core/skbuff.c:203 skb_push+0xf0/0x108 net/core/skbuff.c:2451 eth_header+0x44/0x1f8 net/ethernet/eth.c:83 dev_hard_header include/linux/netdevice.h:3188 [inline] llc_mac_hdr_init+0x110/0x17c net/llc/llc_output.c:33 llc_sap_action_send_xid_c+0x170/0x344 net/llc/llc_s_ac.c:85 llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] llc_sap_next_state net/llc/llc_sap.c:182 [inline] llc_sap_state_process+0x1ec/0x774 net/llc/llc_sap.c:209 llc_build_and_send_xid_pkt+0x12c/0x1c0 net/llc/llc_sap.c:270 llc_ui_sendmsg+0x7bc/0xb1c net/llc/af_llc.c:997 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_sendmsg+0x194/0x274 net/socket.c:767 splice_to_socket+0x7cc/0xd58 fs/splice.c:881 do_splice_from fs/splice.c:933 [inline] direct_splice_actor+0xe4/0x1c0 fs/splice.c:1142 splice_direct_to_actor+0x2a0/0x7e4 fs/splice.c:1088 do_splice_direct+0x20c/0x348 fs/splice.c:1194 do_sendfile+0x4bc/0xc70 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1322 [inline] __se_sys_sendfile64 fs/read_write.c:1308 [inline] __arm64_sys_sendfile64+0x160/0x3b4 fs/read_write.c:1308 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 Code: aa1803e6 aa1903e7 a90023f5 94792f6a (d4210000) Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-and-tested-by: syzbot+2a7024e9502df538e8ef@syzkaller.appspotmail.com Signed-off-by: Eric Dumazet --- net/llc/af_llc.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 9b06c380866b53bcb395bf255587279db025d11d..20551cfb7da6d8dd098c906477895e26c080fe32 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -928,14 +928,15 @@ static int llc_ui_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, */ static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { + DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name); struct sock *sk = sock->sk; struct llc_sock *llc = llc_sk(sk); - DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name); int flags = msg->msg_flags; int noblock = flags & MSG_DONTWAIT; + int rc = -EINVAL, copied = 0, hdrlen, hh_len; struct sk_buff *skb = NULL; + struct net_device *dev; size_t size = 0; - int rc = -EINVAL, copied = 0, hdrlen; dprintk("%s: sending from %02X to %02X\n", __func__, llc->laddr.lsap, llc->daddr.lsap); @@ -955,22 +956,29 @@ static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) if (rc) goto out; } - hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr); + dev = llc->dev; + hh_len = LL_RESERVED_SPACE(dev); + hdrlen = llc_ui_header_len(sk, addr); size = hdrlen + len; - if (size > llc->dev->mtu) - size = llc->dev->mtu; + size = min_t(size_t, size, READ_ONCE(dev->mtu)); copied = size - hdrlen; rc = -EINVAL; if (copied < 0) goto out; release_sock(sk); - skb = sock_alloc_send_skb(sk, size, noblock, &rc); + skb = sock_alloc_send_skb(sk, hh_len + size, noblock, &rc); lock_sock(sk); if (!skb) goto out; - skb->dev = llc->dev; + if (sock_flag(sk, SOCK_ZAPPED) || + llc->dev != dev || + hdrlen != llc_ui_header_len(sk, addr) || + hh_len != LL_RESERVED_SPACE(dev) || + size > READ_ONCE(dev->mtu)) + goto out; + skb->dev = dev; skb->protocol = llc_proto_type(addr->sllc_arphrd); - skb_reserve(skb, hdrlen); + skb_reserve(skb, hh_len + hdrlen); rc = memcpy_from_msg(skb_put(skb, copied), msg, copied); if (rc) goto out; -- 2.43.0.429.g432eaa2c6b-goog