Skip to content
This repository has been archived by the owner on Dec 20, 2023. It is now read-only.

Commit

Permalink
l2tp: fix kernel panic when using IPv4-mapped IPv6 addresses
Browse files Browse the repository at this point in the history 
IPv4 mapped addresses cause kernel panic.
The patch juste check whether the IPv6 address is an IPv4 mapped
address. If so, use IPv4 API instead of IPv6.

[  940.026915] general protection fault: 0000 [#1]
[  940.026915] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core pppox ppp_generic slhc loop psmouse
[  940.026915] CPU: 0 PID: 3184 Comm: memcheck-amd64- Not tainted 3.11.0+ #1
[  940.026915] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[  940.026915] task: ffff880007130e20 ti: ffff88000737e000 task.ti: ffff88000737e000
[  940.026915] RIP: 0010:[<ffffffff81333780>]  [<ffffffff81333780>] ip6_xmit+0x276/0x326
[  940.026915] RSP: 0018:ffff88000737fd28  EFLAGS: 00010286
[  940.026915] RAX: c748521a75ceff48 RBX: ffff880000c30800 RCX: 0000000000000000
[  940.026915] RDX: ffff88000075cc4e RSI: 0000000000000028 RDI: ffff8800060e5a40
[  940.026915] RBP: ffff8800060e5a40 R08: 0000000000000000 R09: ffff88000075cc90
[  940.026915] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88000737fda0
[  940.026915] R13: 0000000000000000 R14: 0000000000002000 R15: ffff880005d3b580
[  940.026915] FS:  00007f163dc5e800(0000) GS:ffffffff81623000(0000) knlGS:0000000000000000
[  940.026915] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  940.026915] CR2: 00000004032dc940 CR3: 0000000005c25000 CR4: 00000000000006f0
[  940.026915] Stack:
[  940.026915]  ffff88000075cc4e ffffffff81694e90 ffff880000c30b38 0000000000000020
[  940.026915]  11000000523c4bac ffff88000737fdb4 0000000000000000 ffff880000c30800
[  940.026915]  ffff880005d3b580 ffff880000c30b38 ffff8800060e5a40 0000000000000020
[  940.026915] Call Trace:
[  940.026915]  [<ffffffff81356cc3>] ? inet6_csk_xmit+0xa4/0xc4
[  940.026915]  [<ffffffffa0038535>] ? l2tp_xmit_skb+0x503/0x55a [l2tp_core]
[  940.026915]  [<ffffffff812b8d3b>] ? pskb_expand_head+0x161/0x214
[  940.026915]  [<ffffffffa003e91d>] ? pppol2tp_xmit+0xf2/0x143 [l2tp_ppp]
[  940.026915]  [<ffffffffa00292e0>] ? ppp_channel_push+0x36/0x8b [ppp_generic]
[  940.026915]  [<ffffffffa00293fe>] ? ppp_write+0xaf/0xc5 [ppp_generic]
[  940.026915]  [<ffffffff8110ead4>] ? vfs_write+0xa2/0x106
[  940.026915]  [<ffffffff8110edd6>] ? SyS_write+0x56/0x8a
[  940.026915]  [<ffffffff81378ac0>] ? system_call_fastpath+0x16/0x1b
[  940.026915] Code: 00 49 8b 8f d8 00 00 00 66 83 7c 11 02 00 74 60 49
8b 47 58 48 83 e0 fe 48 8b 80 18 01 00 00 48 85 c0 74 13 48 8b 80 78 02
00 00 <48> ff 40 28 41 8b 57 68 48 01 50 30 48 8b 54 24 08 49 c7 c1 51
[  940.026915] RIP  [<ffffffff81333780>] ip6_xmit+0x276/0x326
[  940.026915]  RSP <ffff88000737fd28>
[  940.057945] ---[ end trace be8aba9a61c8b7f3 ]---
[  940.058583] Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: François CACHEREUL <f.cachereul@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
@fcachereul @davem330
fcachereul authored and davem330 committed Oct 2, 2013
1 parent 80ad1d6 commit e18503f
Show file tree
Hide file tree
Showing 2 changed files with 26 additions and 4 deletions.
27 changes: 23 additions & 4 deletions net/l2tp/l2tp_core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -496,6 +496,7 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
static inline int l2tp_verify_udp_checksum(struct sock *sk,
struct sk_buff *skb)
{
struct l2tp_tunnel *tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
struct udphdr *uh = udp_hdr(skb);
u16 ulen = ntohs(uh->len);
__wsum psum;
Expand All @@ -504,7 +505,7 @@ static inline int l2tp_verify_udp_checksum(struct sock *sk,
return 0;

#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == PF_INET6) {
if (sk->sk_family == PF_INET6 && !tunnel->v4mapped) {
if (!uh->check) {
LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
return 1;
Expand Down Expand Up @@ -1128,7 +1129,7 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
/* Queue the packet to IP for output */
skb->local_df = 1;
#if IS_ENABLED(CONFIG_IPV6)
if (skb->sk->sk_family == PF_INET6)
if (skb->sk->sk_family == PF_INET6 && !tunnel->v4mapped)
error = inet6_csk_xmit(skb, NULL);
else
#endif
Expand Down Expand Up @@ -1255,7 +1256,7 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len

/* Calculate UDP checksum if configured to do so */
#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == PF_INET6)
if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
l2tp_xmit_ipv6_csum(sk, skb, udp_len);
else
#endif
Expand Down Expand Up @@ -1704,6 +1705,24 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
if (cfg != NULL)
tunnel->debug = cfg->debug;

#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == PF_INET6) {
struct ipv6_pinfo *np = inet6_sk(sk);

if (ipv6_addr_v4mapped(&np->saddr) &&
ipv6_addr_v4mapped(&np->daddr)) {
struct inet_sock *inet = inet_sk(sk);

tunnel->v4mapped = true;
inet->inet_saddr = np->saddr.s6_addr32[3];
inet->inet_rcv_saddr = np->rcv_saddr.s6_addr32[3];
inet->inet_daddr = np->daddr.s6_addr32[3];
} else {
tunnel->v4mapped = false;
}
}
#endif

/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
tunnel->encap = encap;
if (encap == L2TP_ENCAPTYPE_UDP) {
Expand All @@ -1712,7 +1731,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
udp_sk(sk)->encap_destroy = l2tp_udp_encap_destroy;
#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == PF_INET6)
if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
udpv6_encap_enable();
else
#endif
Expand Down
3 changes: 3 additions & 0 deletions net/l2tp/l2tp_core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,9 @@ struct l2tp_tunnel {
struct sock *sock; /* Parent socket */
int fd; /* Parent fd, if tunnel socket
* was created by userspace */
#if IS_ENABLED(CONFIG_IPV6)
bool v4mapped;
#endif

struct work_struct del_work;

Expand Down

0 comments on commit e18503f

Please sign in to comment.