142 lines
5.8 KiB
Diff
142 lines
5.8 KiB
Diff
From 8be4005ed947924104df5850944a20b7f6570137 Mon Sep 17 00:00:00 2001
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From: François CACHEREUL <f.cachereul@alphalink.fr>
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Date: Wed, 2 Oct 2013 10:16:02 +0200
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Subject: l2tp: fix kernel panic when using IPv4-mapped IPv6 addresses
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From: François CACHEREUL <f.cachereul@alphalink.fr>
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[ Upstream commit e18503f41f9b12132c95d7c31ca6ee5155e44e5c ]
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IPv4 mapped addresses cause kernel panic.
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The patch juste check whether the IPv6 address is an IPv4 mapped
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address. If so, use IPv4 API instead of IPv6.
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[ 940.026915] general protection fault: 0000 [#1]
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[ 940.026915] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core pppox ppp_generic slhc loop psmouse
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[ 940.026915] CPU: 0 PID: 3184 Comm: memcheck-amd64- Not tainted 3.11.0+ #1
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[ 940.026915] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
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[ 940.026915] task: ffff880007130e20 ti: ffff88000737e000 task.ti: ffff88000737e000
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[ 940.026915] RIP: 0010:[<ffffffff81333780>] [<ffffffff81333780>] ip6_xmit+0x276/0x326
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[ 940.026915] RSP: 0018:ffff88000737fd28 EFLAGS: 00010286
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[ 940.026915] RAX: c748521a75ceff48 RBX: ffff880000c30800 RCX: 0000000000000000
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[ 940.026915] RDX: ffff88000075cc4e RSI: 0000000000000028 RDI: ffff8800060e5a40
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[ 940.026915] RBP: ffff8800060e5a40 R08: 0000000000000000 R09: ffff88000075cc90
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[ 940.026915] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88000737fda0
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[ 940.026915] R13: 0000000000000000 R14: 0000000000002000 R15: ffff880005d3b580
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[ 940.026915] FS: 00007f163dc5e800(0000) GS:ffffffff81623000(0000) knlGS:0000000000000000
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[ 940.026915] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
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[ 940.026915] CR2: 00000004032dc940 CR3: 0000000005c25000 CR4: 00000000000006f0
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[ 940.026915] Stack:
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[ 940.026915] ffff88000075cc4e ffffffff81694e90 ffff880000c30b38 0000000000000020
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[ 940.026915] 11000000523c4bac ffff88000737fdb4 0000000000000000 ffff880000c30800
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[ 940.026915] ffff880005d3b580 ffff880000c30b38 ffff8800060e5a40 0000000000000020
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[ 940.026915] Call Trace:
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[ 940.026915] [<ffffffff81356cc3>] ? inet6_csk_xmit+0xa4/0xc4
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[ 940.026915] [<ffffffffa0038535>] ? l2tp_xmit_skb+0x503/0x55a [l2tp_core]
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[ 940.026915] [<ffffffff812b8d3b>] ? pskb_expand_head+0x161/0x214
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[ 940.026915] [<ffffffffa003e91d>] ? pppol2tp_xmit+0xf2/0x143 [l2tp_ppp]
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[ 940.026915] [<ffffffffa00292e0>] ? ppp_channel_push+0x36/0x8b [ppp_generic]
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[ 940.026915] [<ffffffffa00293fe>] ? ppp_write+0xaf/0xc5 [ppp_generic]
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[ 940.026915] [<ffffffff8110ead4>] ? vfs_write+0xa2/0x106
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[ 940.026915] [<ffffffff8110edd6>] ? SyS_write+0x56/0x8a
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[ 940.026915] [<ffffffff81378ac0>] ? system_call_fastpath+0x16/0x1b
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[ 940.026915] Code: 00 49 8b 8f d8 00 00 00 66 83 7c 11 02 00 74 60 49
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8b 47 58 48 83 e0 fe 48 8b 80 18 01 00 00 48 85 c0 74 13 48 8b 80 78 02
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00 00 <48> ff 40 28 41 8b 57 68 48 01 50 30 48 8b 54 24 08 49 c7 c1 51
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[ 940.026915] RIP [<ffffffff81333780>] ip6_xmit+0x276/0x326
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[ 940.026915] RSP <ffff88000737fd28>
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[ 940.057945] ---[ end trace be8aba9a61c8b7f3 ]---
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[ 940.058583] Kernel panic - not syncing: Fatal exception in interrupt
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Signed-off-by: François CACHEREUL <f.cachereul@alphalink.fr>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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net/l2tp/l2tp_core.c | 27 +++++++++++++++++++++++----
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net/l2tp/l2tp_core.h | 3 +++
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2 files changed, 26 insertions(+), 4 deletions(-)
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--- a/net/l2tp/l2tp_core.c
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+++ b/net/l2tp/l2tp_core.c
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@@ -496,6 +496,7 @@ out:
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static inline int l2tp_verify_udp_checksum(struct sock *sk,
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struct sk_buff *skb)
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{
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+ struct l2tp_tunnel *tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
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struct udphdr *uh = udp_hdr(skb);
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u16 ulen = ntohs(uh->len);
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__wsum psum;
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@@ -504,7 +505,7 @@ static inline int l2tp_verify_udp_checks
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return 0;
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#if IS_ENABLED(CONFIG_IPV6)
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- if (sk->sk_family == PF_INET6) {
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+ if (sk->sk_family == PF_INET6 && !tunnel->v4mapped) {
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if (!uh->check) {
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LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
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return 1;
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@@ -1128,7 +1129,7 @@ static int l2tp_xmit_core(struct l2tp_se
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/* Queue the packet to IP for output */
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skb->local_df = 1;
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#if IS_ENABLED(CONFIG_IPV6)
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- if (skb->sk->sk_family == PF_INET6)
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+ if (skb->sk->sk_family == PF_INET6 && !tunnel->v4mapped)
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error = inet6_csk_xmit(skb, NULL);
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else
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#endif
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@@ -1255,7 +1256,7 @@ int l2tp_xmit_skb(struct l2tp_session *s
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/* Calculate UDP checksum if configured to do so */
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#if IS_ENABLED(CONFIG_IPV6)
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- if (sk->sk_family == PF_INET6)
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+ if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
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l2tp_xmit_ipv6_csum(sk, skb, udp_len);
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else
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#endif
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@@ -1704,6 +1705,24 @@ int l2tp_tunnel_create(struct net *net,
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if (cfg != NULL)
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tunnel->debug = cfg->debug;
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+#if IS_ENABLED(CONFIG_IPV6)
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+ if (sk->sk_family == PF_INET6) {
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+ struct ipv6_pinfo *np = inet6_sk(sk);
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+
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+ if (ipv6_addr_v4mapped(&np->saddr) &&
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+ ipv6_addr_v4mapped(&np->daddr)) {
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+ struct inet_sock *inet = inet_sk(sk);
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+
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+ tunnel->v4mapped = true;
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+ inet->inet_saddr = np->saddr.s6_addr32[3];
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+ inet->inet_rcv_saddr = np->rcv_saddr.s6_addr32[3];
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+ inet->inet_daddr = np->daddr.s6_addr32[3];
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+ } else {
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+ tunnel->v4mapped = false;
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+ }
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+ }
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+#endif
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+
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/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
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tunnel->encap = encap;
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if (encap == L2TP_ENCAPTYPE_UDP) {
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@@ -1712,7 +1731,7 @@ int l2tp_tunnel_create(struct net *net,
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udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
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udp_sk(sk)->encap_destroy = l2tp_udp_encap_destroy;
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#if IS_ENABLED(CONFIG_IPV6)
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- if (sk->sk_family == PF_INET6)
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+ if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
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udpv6_encap_enable();
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else
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#endif
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--- a/net/l2tp/l2tp_core.h
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+++ b/net/l2tp/l2tp_core.h
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@@ -194,6 +194,9 @@ struct l2tp_tunnel {
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struct sock *sock; /* Parent socket */
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int fd; /* Parent fd, if tunnel socket
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* was created by userspace */
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+#if IS_ENABLED(CONFIG_IPV6)
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+ bool v4mapped;
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+#endif
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struct work_struct del_work;
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