From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZoOw+rwP/UeMSVwjSRDG671h/yEzQo6Aosdd8Xx1M+Yc7+rYVNi76dCAY19So7BCG6dLW28 ARC-Seal: i=1; a=rsa-sha256; t=1524837915; cv=none; d=google.com; s=arc-20160816; b=Q7//soc4Y4qNpFL+SWvYhw2lFRmncRisuYcZnndDmpCeD6DIYVdCuznZGCcDlGeTsn V1CVGL++XHYzfsp5PSMk3GErIUAXcGuSOmmzKZySRy+WdEV8zu0uQbNY+1iiI/QHKtC6 Cca1SI1H+6WexV1pDjtQhGkoQ0SDSx27P+9E4wEC4/V02xX9+mv/dSEfWkUed0frrPV8 iDAHNnO6jweiJTZaoI38KE0HkniUqofsUFUQnUd8S5KpIsvCubyCiKyPiC+uCIpIWSjD wXThmVn8q+qpw/Aj8ifZncfD90dQo5aCtnHRhGRrh7Fe+iFpeOkhwcW1yQagWtJ7hTXD gY0A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:dmarc-filter:arc-authentication-results; bh=/U+DHdBEjmuyrpHTDBPL4kN8S8M7Yr+kUxZ6WLFx+ik=; b=WiBDy8hIx8nvgRK8/Rk2JHmg93w2Ch7zJlCz2P0Cr58q+g4kCuCsQ+qa+KPkEw0J7T N5rjuCI+syGM87iUsgy2YkVdw+SHopG2ibZXCpCr/+HSsvpY40Zp7cDNyqbxNBGuJi4u jEIOkirAmWSU3buHqRr6sHwDTt+ZpqZPLo70fKpted1RO4oVLB1cwlwhbh0cA69s9+XC G5EFag2n693fC6FCay/gKiyAtb9Kw8W2L99NPlExPmwuLnSPd49/Ui7hPKlQzMKeZZ8/ NE2W9KjDJJYSzaQU9UYrNvzFoDb4Fdk5TZOCgJA0HiRjLPi8SJdExefqREMUsXMVyAjM sYMQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of srs0=4/0d=hq=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=4/0d=HQ=linuxfoundation.org=gregkh@kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of srs0=4/0d=hq=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=4/0d=HQ=linuxfoundation.org=gregkh@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8843B2189D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , "David S. Miller" Subject: [PATCH 4.9 66/74] net: af_packet: fix race in PACKET_{R|T}X_RING Date: Fri, 27 Apr 2018 15:58:56 +0200 Message-Id: <20180427135712.679106006@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180427135709.899303463@linuxfoundation.org> References: <20180427135709.899303463@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598908116836629664?= X-GMAIL-MSGID: =?utf-8?q?1598908442295358248?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 5171b37d959641bbc619781caf62e61f7b940871 ] In order to remove the race caught by syzbot [1], we need to lock the socket before using po->tp_version as this could change under us otherwise. This means lock_sock() and release_sock() must be done by packet_set_ring() callers. [1] : BUG: KMSAN: uninit-value in packet_set_ring+0x1254/0x3870 net/packet/af_packet.c:4249 CPU: 0 PID: 20195 Comm: syzkaller707632 Not tainted 4.16.0+ #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 packet_set_ring+0x1254/0x3870 net/packet/af_packet.c:4249 packet_setsockopt+0x12c6/0x5a90 net/packet/af_packet.c:3662 SYSC_setsockopt+0x4b8/0x570 net/socket.c:1849 SyS_setsockopt+0x76/0xa0 net/socket.c:1828 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x449099 RSP: 002b:00007f42b5307ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 000000000070003c RCX: 0000000000449099 RDX: 0000000000000005 RSI: 0000000000000107 RDI: 0000000000000003 RBP: 0000000000700038 R08: 000000000000001c R09: 0000000000000000 R10: 00000000200000c0 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000080eecf R14: 00007f42b53089c0 R15: 0000000000000001 Local variable description: ----req_u@packet_setsockopt Variable was created at: packet_setsockopt+0x13f/0x5a90 net/packet/af_packet.c:3612 SYSC_setsockopt+0x4b8/0x570 net/socket.c:1849 Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3024,6 +3024,7 @@ static int packet_release(struct socket packet_flush_mclist(sk); + lock_sock(sk); if (po->rx_ring.pg_vec) { memset(&req_u, 0, sizeof(req_u)); packet_set_ring(sk, &req_u, 1, 0); @@ -3033,6 +3034,7 @@ static int packet_release(struct socket memset(&req_u, 0, sizeof(req_u)); packet_set_ring(sk, &req_u, 1, 1); } + release_sock(sk); f = fanout_release(sk); @@ -3661,6 +3663,7 @@ packet_setsockopt(struct socket *sock, i union tpacket_req_u req_u; int len; + lock_sock(sk); switch (po->tp_version) { case TPACKET_V1: case TPACKET_V2: @@ -3671,12 +3674,17 @@ packet_setsockopt(struct socket *sock, i len = sizeof(req_u.req3); break; } - if (optlen < len) - return -EINVAL; - if (copy_from_user(&req_u.req, optval, len)) - return -EFAULT; - return packet_set_ring(sk, &req_u, 0, - optname == PACKET_TX_RING); + if (optlen < len) { + ret = -EINVAL; + } else { + if (copy_from_user(&req_u.req, optval, len)) + ret = -EFAULT; + else + ret = packet_set_ring(sk, &req_u, 0, + optname == PACKET_TX_RING); + } + release_sock(sk); + return ret; } case PACKET_COPY_THRESH: { @@ -4247,7 +4255,6 @@ static int packet_set_ring(struct sock * /* Added to avoid minimal code churn */ struct tpacket_req *req = &req_u->req; - lock_sock(sk); /* Opening a Tx-ring is NOT supported in TPACKET_V3 */ if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) { net_warn_ratelimited("Tx-ring is not supported.\n"); @@ -4383,7 +4390,6 @@ static int packet_set_ring(struct sock * if (pg_vec) free_pg_vec(pg_vec, order, req->tp_block_nr); out: - release_sock(sk); return err; }