From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49xq1xAVDQvJFWZ6lOLRVrhsdtt44jYSAIOfZFIaodb+3SD/1Iv0PXQ7KsWlQkkqzuozy6e ARC-Seal: i=1; a=rsa-sha256; t=1523399090; cv=none; d=google.com; s=arc-20160816; b=y25OzSXUL1gXoIlreru7gKlBSrdkUirIKb3IA81ryE+9YeFhvOolNbzurKu2VNCAfq hBtXvnvLqD3vH6h3sgYxNdG4h/LgRDs/DBcCE/LWMs5QZFZBjwn9i4gahlgPySaMqfjo WqJnz9gW0Jgw07cdhIKbXSajpjYI8L77/r0Ehx6cUa0o10cgj0C/diLp3NPxVOZe9KFV nEDosJHtO6pliM5d9tVzRpsyzd+MPdolbgQWH+5uTd+COK/rqIB0Z9fZbhO0ySVyZsdU 2Grm0nbSYNUas2/KFQFqtWdBajrSkm5Xl17RZwCjba5RVjR/g+Wl7ptTa15FkaAtEq8R +6Iw== 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:arc-authentication-results; bh=+arqfKyJfTjSpJV1JdTXKWYmspztIIye2gJBn9IM7l4=; b=1G6XmSqFfcHrnFA4T9j/3ackGkWJiCS8zH/Gn9mkGuhaUwTt/9L4Cn5U8o0HNv7xpj vhTzrfY7QgZ0B3wf34qDwKwwhzb5TllaTh0zieRXgjZQp/e4CjESTbBaJhO4tSXCIWa4 Xzy+SIjmrxIH+gdcHAFBcUKIiwl8ykWsNor9SpWZDhK+GkZxas3mxmIY9spCqy/8wvV+ BcZEsvgNImcX6m4rWTQcw0hmPx1SXaepFEH68u1Kdm2c8KpcHZfKJmy/34Iauw28V02T oyvpXiPNcVpqm1uUbfl/I8YBI7vhtthhXCW3SUFYP/fiQdsdzyNZFYfiTssRLdAhA2Rn Bu3w== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) 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 4.16 13/18] ipv6: sit: better validate user provided tunnel names Date: Wed, 11 Apr 2018 00:23:48 +0200 Message-Id: <20180410212759.286373955@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180410212758.564682823@linuxfoundation.org> References: <20180410212758.564682823@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?1597399724483027149?= X-GMAIL-MSGID: =?utf-8?q?1597399724483027149?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit b95211e066fc3494b7c115060b2297b4ba21f025 ] Use dev_valid_name() to make sure user does not provide illegal device name. syzbot caught the following bug : BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline] BUG: KASAN: stack-out-of-bounds in ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254 Write of size 33 at addr ffff8801b64076d8 by task syzkaller932654/4453 CPU: 0 PID: 4453 Comm: syzkaller932654 Not tainted 4.16.0+ #1 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+0x1b9/0x29f lib/dump_stack.c:53 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 strlcpy include/linux/string.h:300 [inline] ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254 ipip6_tunnel_ioctl+0xe71/0x241b net/ipv6/sit.c:1221 dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334 dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525 sock_ioctl+0x47e/0x680 net/socket.c:1015 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 SYSC_ioctl fs/ioctl.c:708 [inline] SyS_ioctl+0x24/0x30 fs/ioctl.c:706 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/sit.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -250,11 +250,13 @@ static struct ip_tunnel *ipip6_tunnel_lo if (!create) goto failed; - if (parms->name[0]) + if (parms->name[0]) { + if (!dev_valid_name(parms->name)) + goto failed; strlcpy(name, parms->name, IFNAMSIZ); - else + } else { strcpy(name, "sit%d"); - + } dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, ipip6_tunnel_setup); if (!dev)