mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-10-01 01:35:54 -04:00
168 lines
8.4 KiB
Diff
168 lines
8.4 KiB
Diff
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From 32c231164b762dddefa13af5a0101032c70b50ef Mon Sep 17 00:00:00 2001
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From: Guillaume Nault <g.nault@alphalink.fr>
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Date: Fri, 18 Nov 2016 22:13:00 +0100
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Subject: l2tp: fix racy SOCK_ZAPPED flag check in l2tp_ip{,6}_bind()
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Lock socket before checking the SOCK_ZAPPED flag in l2tp_ip6_bind().
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Without lock, a concurrent call could modify the socket flags between
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the sock_flag(sk, SOCK_ZAPPED) test and the lock_sock() call. This way,
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a socket could be inserted twice in l2tp_ip6_bind_table. Releasing it
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would then leave a stale pointer there, generating use-after-free
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errors when walking through the list or modifying adjacent entries.
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BUG: KASAN: use-after-free in l2tp_ip6_close+0x22e/0x290 at addr ffff8800081b0ed8
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Write of size 8 by task syz-executor/10987
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CPU: 0 PID: 10987 Comm: syz-executor Not tainted 4.8.0+ #39
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Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
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ffff880031d97838 ffffffff829f835b ffff88001b5a1640 ffff8800081b0ec0
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ffff8800081b15a0 ffff8800081b6d20 ffff880031d97860 ffffffff8174d3cc
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ffff880031d978f0 ffff8800081b0e80 ffff88001b5a1640 ffff880031d978e0
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Call Trace:
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[<ffffffff829f835b>] dump_stack+0xb3/0x118 lib/dump_stack.c:15
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[<ffffffff8174d3cc>] kasan_object_err+0x1c/0x70 mm/kasan/report.c:156
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[< inline >] print_address_description mm/kasan/report.c:194
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[<ffffffff8174d666>] kasan_report_error+0x1f6/0x4d0 mm/kasan/report.c:283
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[< inline >] kasan_report mm/kasan/report.c:303
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[<ffffffff8174db7e>] __asan_report_store8_noabort+0x3e/0x40 mm/kasan/report.c:329
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[< inline >] __write_once_size ./include/linux/compiler.h:249
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[< inline >] __hlist_del ./include/linux/list.h:622
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[< inline >] hlist_del_init ./include/linux/list.h:637
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[<ffffffff8579047e>] l2tp_ip6_close+0x22e/0x290 net/l2tp/l2tp_ip6.c:239
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[<ffffffff850b2dfd>] inet_release+0xed/0x1c0 net/ipv4/af_inet.c:415
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[<ffffffff851dc5a0>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:422
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[<ffffffff84c4581d>] sock_release+0x8d/0x1d0 net/socket.c:570
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[<ffffffff84c45976>] sock_close+0x16/0x20 net/socket.c:1017
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[<ffffffff817a108c>] __fput+0x28c/0x780 fs/file_table.c:208
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[<ffffffff817a1605>] ____fput+0x15/0x20 fs/file_table.c:244
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[<ffffffff813774f9>] task_work_run+0xf9/0x170
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[<ffffffff81324aae>] do_exit+0x85e/0x2a00
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[<ffffffff81326dc8>] do_group_exit+0x108/0x330
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[<ffffffff81348cf7>] get_signal+0x617/0x17a0 kernel/signal.c:2307
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[<ffffffff811b49af>] do_signal+0x7f/0x18f0
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[<ffffffff810039bf>] exit_to_usermode_loop+0xbf/0x150 arch/x86/entry/common.c:156
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[< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190
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[<ffffffff81006060>] syscall_return_slowpath+0x1a0/0x1e0 arch/x86/entry/common.c:259
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[<ffffffff85e4d726>] entry_SYSCALL_64_fastpath+0xc4/0xc6
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Object at ffff8800081b0ec0, in cache L2TP/IPv6 size: 1448
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Allocated:
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PID = 10987
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[ 1116.897025] [<ffffffff811ddcb6>] save_stack_trace+0x16/0x20
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[ 1116.897025] [<ffffffff8174c736>] save_stack+0x46/0xd0
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[ 1116.897025] [<ffffffff8174c9ad>] kasan_kmalloc+0xad/0xe0
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[ 1116.897025] [<ffffffff8174cee2>] kasan_slab_alloc+0x12/0x20
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[ 1116.897025] [< inline >] slab_post_alloc_hook mm/slab.h:417
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[ 1116.897025] [< inline >] slab_alloc_node mm/slub.c:2708
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[ 1116.897025] [< inline >] slab_alloc mm/slub.c:2716
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[ 1116.897025] [<ffffffff817476a8>] kmem_cache_alloc+0xc8/0x2b0 mm/slub.c:2721
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[ 1116.897025] [<ffffffff84c4f6a9>] sk_prot_alloc+0x69/0x2b0 net/core/sock.c:1326
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[ 1116.897025] [<ffffffff84c58ac8>] sk_alloc+0x38/0xae0 net/core/sock.c:1388
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[ 1116.897025] [<ffffffff851ddf67>] inet6_create+0x2d7/0x1000 net/ipv6/af_inet6.c:182
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[ 1116.897025] [<ffffffff84c4af7b>] __sock_create+0x37b/0x640 net/socket.c:1153
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[ 1116.897025] [< inline >] sock_create net/socket.c:1193
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[ 1116.897025] [< inline >] SYSC_socket net/socket.c:1223
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[ 1116.897025] [<ffffffff84c4b46f>] SyS_socket+0xef/0x1b0 net/socket.c:1203
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[ 1116.897025] [<ffffffff85e4d685>] entry_SYSCALL_64_fastpath+0x23/0xc6
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Freed:
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PID = 10987
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[ 1116.897025] [<ffffffff811ddcb6>] save_stack_trace+0x16/0x20
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[ 1116.897025] [<ffffffff8174c736>] save_stack+0x46/0xd0
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[ 1116.897025] [<ffffffff8174cf61>] kasan_slab_free+0x71/0xb0
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[ 1116.897025] [< inline >] slab_free_hook mm/slub.c:1352
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[ 1116.897025] [< inline >] slab_free_freelist_hook mm/slub.c:1374
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[ 1116.897025] [< inline >] slab_free mm/slub.c:2951
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[ 1116.897025] [<ffffffff81748b28>] kmem_cache_free+0xc8/0x330 mm/slub.c:2973
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[ 1116.897025] [< inline >] sk_prot_free net/core/sock.c:1369
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[ 1116.897025] [<ffffffff84c541eb>] __sk_destruct+0x32b/0x4f0 net/core/sock.c:1444
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[ 1116.897025] [<ffffffff84c5aca4>] sk_destruct+0x44/0x80 net/core/sock.c:1452
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[ 1116.897025] [<ffffffff84c5ad33>] __sk_free+0x53/0x220 net/core/sock.c:1460
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[ 1116.897025] [<ffffffff84c5af23>] sk_free+0x23/0x30 net/core/sock.c:1471
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[ 1116.897025] [<ffffffff84c5cb6c>] sk_common_release+0x28c/0x3e0 ./include/net/sock.h:1589
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[ 1116.897025] [<ffffffff8579044e>] l2tp_ip6_close+0x1fe/0x290 net/l2tp/l2tp_ip6.c:243
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[ 1116.897025] [<ffffffff850b2dfd>] inet_release+0xed/0x1c0 net/ipv4/af_inet.c:415
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[ 1116.897025] [<ffffffff851dc5a0>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:422
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[ 1116.897025] [<ffffffff84c4581d>] sock_release+0x8d/0x1d0 net/socket.c:570
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[ 1116.897025] [<ffffffff84c45976>] sock_close+0x16/0x20 net/socket.c:1017
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[ 1116.897025] [<ffffffff817a108c>] __fput+0x28c/0x780 fs/file_table.c:208
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[ 1116.897025] [<ffffffff817a1605>] ____fput+0x15/0x20 fs/file_table.c:244
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[ 1116.897025] [<ffffffff813774f9>] task_work_run+0xf9/0x170
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[ 1116.897025] [<ffffffff81324aae>] do_exit+0x85e/0x2a00
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[ 1116.897025] [<ffffffff81326dc8>] do_group_exit+0x108/0x330
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[ 1116.897025] [<ffffffff81348cf7>] get_signal+0x617/0x17a0 kernel/signal.c:2307
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[ 1116.897025] [<ffffffff811b49af>] do_signal+0x7f/0x18f0
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[ 1116.897025] [<ffffffff810039bf>] exit_to_usermode_loop+0xbf/0x150 arch/x86/entry/common.c:156
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[ 1116.897025] [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190
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[ 1116.897025] [<ffffffff81006060>] syscall_return_slowpath+0x1a0/0x1e0 arch/x86/entry/common.c:259
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[ 1116.897025] [<ffffffff85e4d726>] entry_SYSCALL_64_fastpath+0xc4/0xc6
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Memory state around the buggy address:
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ffff8800081b0d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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ffff8800081b0e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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>ffff8800081b0e80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
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^
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ffff8800081b0f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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ffff8800081b0f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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==================================================================
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The same issue exists with l2tp_ip_bind() and l2tp_ip_bind_table.
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Fixes: c51ce49735c1 ("l2tp: fix oops in L2TP IP sockets for connect() AF_UNSPEC case")
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Reported-by: Baozeng Ding <sploving1@gmail.com>
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Reported-by: Andrey Konovalov <andreyknvl@google.com>
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Tested-by: Baozeng Ding <sploving1@gmail.com>
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Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/l2tp/l2tp_ip.c | 5 +++--
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net/l2tp/l2tp_ip6.c | 5 +++--
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2 files changed, 6 insertions(+), 4 deletions(-)
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diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
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index fce25af..982f6c4 100644
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--- a/net/l2tp/l2tp_ip.c
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+++ b/net/l2tp/l2tp_ip.c
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@@ -251,8 +251,6 @@ static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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int ret;
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int chk_addr_ret;
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- if (!sock_flag(sk, SOCK_ZAPPED))
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- return -EINVAL;
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if (addr_len < sizeof(struct sockaddr_l2tpip))
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return -EINVAL;
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if (addr->l2tp_family != AF_INET)
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@@ -267,6 +265,9 @@ static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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read_unlock_bh(&l2tp_ip_lock);
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lock_sock(sk);
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+ if (!sock_flag(sk, SOCK_ZAPPED))
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+ goto out;
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+
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if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
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goto out;
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diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
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index ad3468c..9978d01 100644
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--- a/net/l2tp/l2tp_ip6.c
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+++ b/net/l2tp/l2tp_ip6.c
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@@ -269,8 +269,6 @@ static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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int addr_type;
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int err;
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- if (!sock_flag(sk, SOCK_ZAPPED))
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- return -EINVAL;
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if (addr->l2tp_family != AF_INET6)
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return -EINVAL;
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if (addr_len < sizeof(*addr))
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@@ -296,6 +294,9 @@ static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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lock_sock(sk);
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err = -EINVAL;
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+ if (!sock_flag(sk, SOCK_ZAPPED))
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+ goto out_unlock;
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+
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if (sk->sk_state != TCP_CLOSE)
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goto out_unlock;
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--
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cgit v1.1
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