From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/O4ESQYD2sHb6qrZdqytDMC46FD0nWc+EI+L7f7kAU+mQbsst07hkx84UGT3KBdVN5rIQx ARC-Seal: i=1; a=rsa-sha256; t=1523472184; cv=none; d=google.com; s=arc-20160816; b=t8zn1hjmpP57/4w2kyb8OBwEmTtsM1ffzACGmtS71MM+Ilvq58ihkT706F9X7xmVJj ONTSadPCfVarjPdp4iOHC3RWd12TZFkLJ9BI9q4lxo7gTCrkLKewdDx5J7KI49lbVa3x iKrZo0mhUiHUbjW1GJQEyo4pBGIN6bgs/iuGLQXBvdKwuHKzUg1oL6xlHFAvH2Z2u/tc JsSUN7FNkcSs3QjHNBZ2dLZI8+95UvU31F+PnlxXPISyuwGdO2o6wHroo0N7K1j+gttl u+hCkPIaOelIpDeNJVjHxgrmQlQDFMtBZlnfTbr4Afw9QBfBIjY6x8P/RarslzYu/2Mt wLmg== 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=+VMHHvqfHxXrpXdEi26ZWJqCBnXxIJ4viy2HiGwDq9g=; b=tBzFxj03vTsx6b52n+SnAx/Bp7kuiiHNq+yVGbMIvsH183f7I8Al3qWLw9HdyI551h bIA7km+5EHyzoV6yoXQAhCuxcqksoWBcbWzBkz2PT0lA08yix3y4pXzswwQN6vGaI+TY KrkrVkLUXxgp7oCtzgu67bII5M3PJKlLpXmphqAbEm6pjWPnPRewOuqIV9ppNjs51Qdp cD1ds4sbnIjf1CcX25mF4vhdxgONN28JEV+3XKUPRV01zLoJttaS+EG3MxPiLe4ufjOL cAFSf2/7nHLU/tyW2dDQ01QvFCCNWdvV7q1bSQ7R3/XrhElT3PRhXEyvsFwD1nNbsvOa UfQw== 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 3.18 116/121] ip6_gre: better validate user provided tunnel names Date: Wed, 11 Apr 2018 20:36:59 +0200 Message-Id: <20180411183503.985288454@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180411183456.195010921@linuxfoundation.org> References: <20180411183456.195010921@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?1597476369362751797?= X-GMAIL-MSGID: =?utf-8?q?1597476369362751797?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 5f42df013b8bc1b6511af7a04bf93b014884ae2a ] 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 ip6gre_tunnel_locate+0x334/0x860 net/ipv6/ip6_gre.c:339 Write of size 20 at addr ffff8801afb9f7b8 by task syzkaller851048/4466 CPU: 1 PID: 4466 Comm: syzkaller851048 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] ip6gre_tunnel_locate+0x334/0x860 net/ipv6/ip6_gre.c:339 ip6gre_tunnel_ioctl+0x69d/0x12e0 net/ipv6/ip6_gre.c:1195 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: c12b395a4664 ("gre: Support GRE over IPv6") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_gre.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -320,11 +320,13 @@ static struct ip6_tnl *ip6gre_tunnel_loc if (t || !create) return t; - if (parms->name[0]) + if (parms->name[0]) { + if (!dev_valid_name(parms->name)) + return NULL; strlcpy(name, parms->name, IFNAMSIZ); - else + } else { strcpy(name, "ip6gre%d"); - + } dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, ip6gre_tunnel_setup); if (!dev)