linux.git/net/x25, branch v5.4.64 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git net/x25: Fix null-ptr-deref in x25_disconnect 2020-08-05T07:59:44+00:00 YueHaibing yuehaibing@huawei.com 2020-04-28T08:12:08+00:00 bbb13adb07affddc2cf2559ef0697cf0ef2c1974 commit 8999dc89497ab1c80d0718828e838c7cd5f6bffe upstream. We should check null before do x25_neigh_put in x25_disconnect, otherwise may cause null-ptr-deref like this: #include <sys/socket.h> #include <linux/x25.h> int main() { int sck_x25; sck_x25 = socket(AF_X25, SOCK_SEQPACKET, 0); close(sck_x25); return 0; } BUG: kernel NULL pointer dereference, address: 00000000000000d8 CPU: 0 PID: 4817 Comm: t2 Not tainted 5.7.0-rc3+ #159 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3- RIP: 0010:x25_disconnect+0x91/0xe0 Call Trace: x25_release+0x18a/0x1b0 __sock_release+0x3d/0xc0 sock_close+0x13/0x20 __fput+0x107/0x270 ____fput+0x9/0x10 task_work_run+0x6d/0xb0 exit_to_usermode_loop+0x102/0x110 do_syscall_64+0x23c/0x260 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Reported-by: syzbot+6db548b615e5aeefdce2@syzkaller.appspotmail.com Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8999dc89497ab1c80d0718828e838c7cd5f6bffe upstream.

We should check null before do x25_neigh_put in x25_disconnect,
otherwise may cause null-ptr-deref like this:

 #include <sys/socket.h>
 #include <linux/x25.h>

 int main() {
    int sck_x25;
    sck_x25 = socket(AF_X25, SOCK_SEQPACKET, 0);
    close(sck_x25);
    return 0;
 }

BUG: kernel NULL pointer dereference, address: 00000000000000d8
CPU: 0 PID: 4817 Comm: t2 Not tainted 5.7.0-rc3+ #159
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-
RIP: 0010:x25_disconnect+0x91/0xe0
Call Trace:
 x25_release+0x18a/0x1b0
 __sock_release+0x3d/0xc0
 sock_close+0x13/0x20
 __fput+0x107/0x270
 ____fput+0x9/0x10
 task_work_run+0x6d/0xb0
 exit_to_usermode_loop+0x102/0x110
 do_syscall_64+0x23c/0x260
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Reported-by: syzbot+6db548b615e5aeefdce2@syzkaller.appspotmail.com
Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/x25: Fix x25_neigh refcnt leak when x25 disconnect 2020-08-05T07:59:44+00:00 Xiyu Yang xiyuyang19@fudan.edu.cn 2020-04-25T13:06:25+00:00 69cd304cfa5cfb0f130488af579c143382432766 commit 4becb7ee5b3d2829ed7b9261a245a77d5b7de902 upstream. x25_connect() invokes x25_get_neigh(), which returns a reference of the specified x25_neigh object to "x25->neighbour" with increased refcnt. When x25 connect success and returns, the reference still be hold by "x25->neighbour", so the refcount should be decreased in x25_disconnect() to keep refcount balanced. The reference counting issue happens in x25_disconnect(), which forgets to decrease the refcnt increased by x25_get_neigh() in x25_connect(), causing a refcnt leak. Fix this issue by calling x25_neigh_put() before x25_disconnect() returns. Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4becb7ee5b3d2829ed7b9261a245a77d5b7de902 upstream.

x25_connect() invokes x25_get_neigh(), which returns a reference of the
specified x25_neigh object to "x25->neighbour" with increased refcnt.

When x25 connect success and returns, the reference still be hold by
"x25->neighbour", so the refcount should be decreased in
x25_disconnect() to keep refcount balanced.

The reference counting issue happens in x25_disconnect(), which forgets
to decrease the refcnt increased by x25_get_neigh() in x25_connect(),
causing a refcnt leak.

Fix this issue by calling x25_neigh_put() before x25_disconnect()
returns.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/x25: Fix x25_neigh refcnt leak when receiving frame 2020-04-29T14:33:09+00:00 Xiyu Yang xiyuyang19@fudan.edu.cn 2020-04-23T05:13:03+00:00 5a2ddf8e5a5d280fe9399d928db612bf1e4d3b03 [ Upstream commit f35d12971b4d814cdb2f659d76b42f0c545270b6 ] x25_lapb_receive_frame() invokes x25_get_neigh(), which returns a reference of the specified x25_neigh object to "nb" with increased refcnt. When x25_lapb_receive_frame() returns, local variable "nb" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in one path of x25_lapb_receive_frame(). When pskb_may_pull() returns false, the function forgets to decrease the refcnt increased by x25_get_neigh(), causing a refcnt leak. Fix this issue by calling x25_neigh_put() when pskb_may_pull() returns false. Fixes: cb101ed2c3c7 ("x25: Handle undersized/fragmented skbs") Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit f35d12971b4d814cdb2f659d76b42f0c545270b6 ]

x25_lapb_receive_frame() invokes x25_get_neigh(), which returns a
reference of the specified x25_neigh object to "nb" with increased
refcnt.

When x25_lapb_receive_frame() returns, local variable "nb" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one path of
x25_lapb_receive_frame(). When pskb_may_pull() returns false, the
function forgets to decrease the refcnt increased by x25_get_neigh(),
causing a refcnt leak.

Fix this issue by calling x25_neigh_put() when pskb_may_pull() returns
false.

Fixes: cb101ed2c3c7 ("x25: Handle undersized/fragmented skbs")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/x25: fix nonblocking connect 2020-01-29T15:45:33+00:00 Martin Schiller ms@dev.tdt.de 2020-01-09T06:31:14+00:00 d8a11e0f4e26f033a217a24617c11bcd24b8f65a commit e21dba7a4df4d93da237da65a096084b4f2e87b4 upstream. This patch fixes 2 issues in x25_connect(): 1. It makes absolutely no sense to reset the neighbour and the connection state after a (successful) nonblocking call of x25_connect. This prevents any connection from being established, since the response (call accept) cannot be processed. 2. Any further calls to x25_connect() while a call is pending should simply return, instead of creating new Call Request (on different logical channels). This patch should also fix the "KASAN: null-ptr-deref Write in x25_connect" and "BUG: unable to handle kernel NULL pointer dereference in x25_connect" bugs reported by syzbot. Signed-off-by: Martin Schiller <ms@dev.tdt.de> Reported-by: syzbot+429c200ffc8772bfe070@syzkaller.appspotmail.com Reported-by: syzbot+eec0c87f31a7c3b66f7b@syzkaller.appspotmail.com Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e21dba7a4df4d93da237da65a096084b4f2e87b4 upstream.

This patch fixes 2 issues in x25_connect():

1. It makes absolutely no sense to reset the neighbour and the
connection state after a (successful) nonblocking call of x25_connect.
This prevents any connection from being established, since the response
(call accept) cannot be processed.

2. Any further calls to x25_connect() while a call is pending should
simply return, instead of creating new Call Request (on different
logical channels).

This patch should also fix the "KASAN: null-ptr-deref Write in
x25_connect" and "BUG: unable to handle kernel NULL pointer dereference
in x25_connect" bugs reported by syzbot.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Reported-by: syzbot+429c200ffc8772bfe070@syzkaller.appspotmail.com
Reported-by: syzbot+eec0c87f31a7c3b66f7b@syzkaller.appspotmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: silence KCSAN warnings around sk_add_backlog() calls 2019-10-10T04:42:59+00:00 Eric Dumazet edumazet@google.com 2019-10-09T22:21:13+00:00 8265792bf8871acc2d00fd03883d830e2249d395 sk_add_backlog() callers usually read sk->sk_rcvbuf without owning the socket lock. This means sk_rcvbuf value can be changed by other cpus, and KCSAN complains. Add READ_ONCE() annotations to document the lockless nature of these reads. Note that writes over sk_rcvbuf should also use WRITE_ONCE(), but this will be done in separate patches to ease stable backports (if we decide this is relevant for stable trees). BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg write to 0xffff88812ab369f8 of 8 bytes by interrupt on cpu 1: __sk_add_backlog include/net/sock.h:902 [inline] sk_add_backlog include/net/sock.h:933 [inline] tcp_add_backlog+0x45a/0xcc0 net/ipv4/tcp_ipv4.c:1737 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208 napi_skb_finish net/core/dev.c:5671 [inline] napi_gro_receive+0x28f/0x330 net/core/dev.c:5704 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061 virtnet_receive drivers/net/virtio_net.c:1323 [inline] virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428 napi_poll net/core/dev.c:6352 [inline] net_rx_action+0x3ae/0xa50 net/core/dev.c:6418 read to 0xffff88812ab369f8 of 8 bytes by task 7271 on cpu 0: tcp_recvmsg+0x470/0x1a30 net/ipv4/tcp.c:2047 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7271 Comm: syz-fuzzer Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> 
sk_add_backlog() callers usually read sk->sk_rcvbuf without
owning the socket lock. This means sk_rcvbuf value can
be changed by other cpus, and KCSAN complains.

Add READ_ONCE() annotations to document the lockless nature
of these reads.

Note that writes over sk_rcvbuf should also use WRITE_ONCE(),
but this will be done in separate patches to ease stable
backports (if we decide this is relevant for stable trees).

BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg

write to 0xffff88812ab369f8 of 8 bytes by interrupt on cpu 1:
 __sk_add_backlog include/net/sock.h:902 [inline]
 sk_add_backlog include/net/sock.h:933 [inline]
 tcp_add_backlog+0x45a/0xcc0 net/ipv4/tcp_ipv4.c:1737
 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925
 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118
 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208
 napi_skb_finish net/core/dev.c:5671 [inline]
 napi_gro_receive+0x28f/0x330 net/core/dev.c:5704
 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061
 virtnet_receive drivers/net/virtio_net.c:1323 [inline]
 virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428
 napi_poll net/core/dev.c:6352 [inline]
 net_rx_action+0x3ae/0xa50 net/core/dev.c:6418

read to 0xffff88812ab369f8 of 8 bytes by task 7271 on cpu 0:
 tcp_recvmsg+0x470/0x1a30 net/ipv4/tcp.c:2047
 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:871 [inline]
 sock_recvmsg net/socket.c:889 [inline]
 sock_recvmsg+0x92/0xb0 net/socket.c:885
 sock_read_iter+0x15f/0x1e0 net/socket.c:967
 call_read_iter include/linux/fs.h:1864 [inline]
 new_sync_read+0x389/0x4f0 fs/read_write.c:414
 __vfs_read+0xb1/0xc0 fs/read_write.c:427
 vfs_read fs/read_write.c:461 [inline]
 vfs_read+0x143/0x2c0 fs/read_write.c:446
 ksys_read+0xd5/0x1b0 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read fs/read_write.c:595 [inline]
 __x64_sys_read+0x4c/0x60 fs/read_write.c:595
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7271 Comm: syz-fuzzer Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 41 2019-05-24T15:27:12+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-20T17:08:06+00:00 ee5d8f4d89eef00f3659f0327038fd64927ed17a Based on 1 normalized pattern(s): this module is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 18 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Based on 1 normalized pattern(s):

  this module is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 18 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21T08:50:46+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-19T12:07:45+00:00 ec8f24b7faaf3d4799a7c3f4c1b87f6b02778ad1 Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: rework SIOCGSTAMP ioctl handling 2019-04-19T21:07:40+00:00 Arnd Bergmann arnd@arndb.de 2019-04-17T20:51:48+00:00 c7cbdbf29f488a19982cd9f4a109887f18028bbb The SIOCGSTAMP/SIOCGSTAMPNS ioctl commands are implemented by many socket protocol handlers, and all of those end up calling the same sock_get_timestamp()/sock_get_timestampns() helper functions, which results in a lot of duplicate code. With the introduction of 64-bit time_t on 32-bit architectures, this gets worse, as we then need four different ioctl commands in each socket protocol implementation. To simplify that, let's add a new .gettstamp() operation in struct proto_ops, and move ioctl implementation into the common sock_ioctl()/compat_sock_ioctl_trans() functions that these all go through. We can reuse the sock_get_timestamp() implementation, but generalize it so it can deal with both native and compat mode, as well as timeval and timespec structures. Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> Link: https://lore.kernel.org/lkml/CAK8P3a038aDQQotzua_QtKGhq8O9n+rdiz2=WDCp82ys8eUT+A@mail.gmail.com/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The SIOCGSTAMP/SIOCGSTAMPNS ioctl commands are implemented by many
socket protocol handlers, and all of those end up calling the same
sock_get_timestamp()/sock_get_timestampns() helper functions, which
results in a lot of duplicate code.

With the introduction of 64-bit time_t on 32-bit architectures, this
gets worse, as we then need four different ioctl commands in each
socket protocol implementation.

To simplify that, let's add a new .gettstamp() operation in
struct proto_ops, and move ioctl implementation into the common
sock_ioctl()/compat_sock_ioctl_trans() functions that these all go
through.

We can reuse the sock_get_timestamp() implementation, but generalize
it so it can deal with both native and compat mode, as well as
timeval and timespec structures.

Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/lkml/CAK8P3a038aDQQotzua_QtKGhq8O9n+rdiz2=WDCp82ys8eUT+A@mail.gmail.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/x25: reset state in x25_connect() 2019-03-11T22:40:14+00:00 Eric Dumazet edumazet@google.com 2019-03-11T20:48:44+00:00 ee74d0bd4325efb41e38affe5955f920ed973f23 In case x25_connect() fails and frees the socket neighbour, we also need to undo the change done to x25->state. Before my last bug fix, we had use-after-free so this patch fixes a latent bug. syzbot report : kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 16137 Comm: syz-executor.1 Not tainted 5.0.0+ #117 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:x25_write_internal+0x1e8/0xdf0 net/x25/x25_subr.c:173 Code: 00 40 88 b5 e0 fe ff ff 0f 85 01 0b 00 00 48 8b 8b 80 04 00 00 48 ba 00 00 00 00 00 fc ff df 48 8d 79 1c 48 89 fe 48 c1 ee 03 <0f> b6 34 16 48 89 fa 83 e2 07 83 c2 03 40 38 f2 7c 09 40 84 f6 0f RSP: 0018:ffff888076717a08 EFLAGS: 00010207 RAX: ffff88805f2f2292 RBX: ffff8880a0ae6000 RCX: 0000000000000000 kobject: 'loop5' (0000000018d0d0ee): kobject_uevent_env RDX: dffffc0000000000 RSI: 0000000000000003 RDI: 000000000000001c RBP: ffff888076717b40 R08: ffff8880950e0580 R09: ffffed100be5e46d R10: ffffed100be5e46c R11: ffff88805f2f2363 R12: ffff888065579840 kobject: 'loop5' (0000000018d0d0ee): fill_kobj_path: path = '/devices/virtual/block/loop5' R13: 1ffff1100ece2f47 R14: 0000000000000013 R15: 0000000000000013 FS: 00007fb88cf43700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9a42a41028 CR3: 0000000087a67000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: x25_release+0xd0/0x340 net/x25/af_x25.c:658 __sock_release+0xd3/0x2b0 net/socket.c:579 sock_close+0x1b/0x30 net/socket.c:1162 __fput+0x2df/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 get_signal+0x1961/0x1d50 kernel/signal.c:2388 do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457f29 Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb88cf42c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffe00 RBX: 0000000000000003 RCX: 0000000000457f29 RDX: 0000000000000012 RSI: 0000000020000080 RDI: 0000000000000004 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb88cf436d4 R13: 00000000004be462 R14: 00000000004cec98 R15: 00000000ffffffff Modules linked in: Fixes: 95d6ebd53c79 ("net/x25: fix use-after-free in x25_device_event()") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: andrew hendry <andrew.hendry@gmail.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
In case x25_connect() fails and frees the socket neighbour,
we also need to undo the change done to x25->state.

Before my last bug fix, we had use-after-free so this
patch fixes a latent bug.

syzbot report :

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 16137 Comm: syz-executor.1 Not tainted 5.0.0+ #117
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:x25_write_internal+0x1e8/0xdf0 net/x25/x25_subr.c:173
Code: 00 40 88 b5 e0 fe ff ff 0f 85 01 0b 00 00 48 8b 8b 80 04 00 00 48 ba 00 00 00 00 00 fc ff df 48 8d 79 1c 48 89 fe 48 c1 ee 03 <0f> b6 34 16 48 89 fa 83 e2 07 83 c2 03 40 38 f2 7c 09 40 84 f6 0f
RSP: 0018:ffff888076717a08 EFLAGS: 00010207
RAX: ffff88805f2f2292 RBX: ffff8880a0ae6000 RCX: 0000000000000000
kobject: 'loop5' (0000000018d0d0ee): kobject_uevent_env
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: 000000000000001c
RBP: ffff888076717b40 R08: ffff8880950e0580 R09: ffffed100be5e46d
R10: ffffed100be5e46c R11: ffff88805f2f2363 R12: ffff888065579840
kobject: 'loop5' (0000000018d0d0ee): fill_kobj_path: path = '/devices/virtual/block/loop5'
R13: 1ffff1100ece2f47 R14: 0000000000000013 R15: 0000000000000013
FS:  00007fb88cf43700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a42a41028 CR3: 0000000087a67000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 x25_release+0xd0/0x340 net/x25/af_x25.c:658
 __sock_release+0xd3/0x2b0 net/socket.c:579
 sock_close+0x1b/0x30 net/socket.c:1162
 __fput+0x2df/0x8d0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 get_signal+0x1961/0x1d50 kernel/signal.c:2388
 do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457f29
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb88cf42c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffe00 RBX: 0000000000000003 RCX: 0000000000457f29
RDX: 0000000000000012 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb88cf436d4
R13: 00000000004be462 R14: 00000000004cec98 R15: 00000000ffffffff
Modules linked in:

Fixes: 95d6ebd53c79 ("net/x25: fix use-after-free in x25_device_event()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: andrew hendry <andrew.hendry@gmail.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/x25: fix use-after-free in x25_device_event() 2019-03-10T18:03:59+00:00 Eric Dumazet edumazet@google.com 2019-03-10T16:07:14+00:00 95d6ebd53c79522bf9502dbc7e89e0d63f94dae4 In case of failure x25_connect() does a x25_neigh_put(x25->neighbour) but forgets to clear x25->neighbour pointer, thus triggering use-after-free. Since the socket is visible in x25_list, we need to hold x25_list_lock to protect the operation. syzbot report : BUG: KASAN: use-after-free in x25_kill_by_device net/x25/af_x25.c:217 [inline] BUG: KASAN: use-after-free in x25_device_event+0x296/0x2b0 net/x25/af_x25.c:252 Read of size 8 at addr ffff8880a030edd0 by task syz-executor003/7854 CPU: 0 PID: 7854 Comm: syz-executor003 Not tainted 5.0.0+ #97 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 x25_kill_by_device net/x25/af_x25.c:217 [inline] x25_device_event+0x296/0x2b0 net/x25/af_x25.c:252 notifier_call_chain+0xc7/0x240 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739 call_netdevice_notifiers_extack net/core/dev.c:1751 [inline] call_netdevice_notifiers net/core/dev.c:1765 [inline] __dev_notify_flags+0x1e9/0x2c0 net/core/dev.c:7607 dev_change_flags+0x10d/0x170 net/core/dev.c:7643 dev_ifsioc+0x2b0/0x940 net/core/dev_ioctl.c:237 dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:488 sock_do_ioctl+0x1bd/0x300 net/socket.c:995 sock_ioctl+0x32b/0x610 net/socket.c:1096 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4467c9 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fdbea222d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006dbc58 RCX: 00000000004467c9 RDX: 0000000020000340 RSI: 0000000000008914 RDI: 0000000000000003 RBP: 00000000006dbc50 R08: 00007fdbea223700 R09: 0000000000000000 R10: 00007fdbea223700 R11: 0000000000000246 R12: 00000000006dbc5c R13: 6000030030626669 R14: 0000000000000000 R15: 0000000030626669 Allocated by task 7843: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:509 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3615 kmalloc include/linux/slab.h:545 [inline] x25_link_device_up+0x46/0x3f0 net/x25/x25_link.c:249 x25_device_event+0x116/0x2b0 net/x25/af_x25.c:242 notifier_call_chain+0xc7/0x240 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739 call_netdevice_notifiers_extack net/core/dev.c:1751 [inline] call_netdevice_notifiers net/core/dev.c:1765 [inline] __dev_notify_flags+0x121/0x2c0 net/core/dev.c:7605 dev_change_flags+0x10d/0x170 net/core/dev.c:7643 dev_ifsioc+0x2b0/0x940 net/core/dev_ioctl.c:237 dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:488 sock_do_ioctl+0x1bd/0x300 net/socket.c:995 sock_ioctl+0x32b/0x610 net/socket.c:1096 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7865: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465 __cache_free mm/slab.c:3494 [inline] kfree+0xcf/0x230 mm/slab.c:3811 x25_neigh_put include/net/x25.h:253 [inline] x25_connect+0x8d8/0xde0 net/x25/af_x25.c:824 __sys_connect+0x266/0x330 net/socket.c:1685 __do_sys_connect net/socket.c:1696 [inline] __se_sys_connect net/socket.c:1693 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1693 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a030edc0 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 16 bytes inside of 256-byte region [ffff8880a030edc0, ffff8880a030eec0) The buggy address belongs to the page: page:ffffea000280c380 count:1 mapcount:0 mapping:ffff88812c3f07c0 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002806788 ffffea00027f0188 ffff88812c3f07c0 raw: 0000000000000000 ffff8880a030e000 000000010000000c 0000000000000000 page dumped because: kasan: bad access detected Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot+04babcefcd396fabec37@syzkaller.appspotmail.com Cc: andrew hendry <andrew.hendry@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
In case of failure x25_connect() does a x25_neigh_put(x25->neighbour)
but forgets to clear x25->neighbour pointer, thus triggering use-after-free.

Since the socket is visible in x25_list, we need to hold x25_list_lock
to protect the operation.

syzbot report :

BUG: KASAN: use-after-free in x25_kill_by_device net/x25/af_x25.c:217 [inline]
BUG: KASAN: use-after-free in x25_device_event+0x296/0x2b0 net/x25/af_x25.c:252
Read of size 8 at addr ffff8880a030edd0 by task syz-executor003/7854

CPU: 0 PID: 7854 Comm: syz-executor003 Not tainted 5.0.0+ #97
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 x25_kill_by_device net/x25/af_x25.c:217 [inline]
 x25_device_event+0x296/0x2b0 net/x25/af_x25.c:252
 notifier_call_chain+0xc7/0x240 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739
 call_netdevice_notifiers_extack net/core/dev.c:1751 [inline]
 call_netdevice_notifiers net/core/dev.c:1765 [inline]
 __dev_notify_flags+0x1e9/0x2c0 net/core/dev.c:7607
 dev_change_flags+0x10d/0x170 net/core/dev.c:7643
 dev_ifsioc+0x2b0/0x940 net/core/dev_ioctl.c:237
 dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:488
 sock_do_ioctl+0x1bd/0x300 net/socket.c:995
 sock_ioctl+0x32b/0x610 net/socket.c:1096
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4467c9
Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fdbea222d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dbc58 RCX: 00000000004467c9
RDX: 0000000020000340 RSI: 0000000000008914 RDI: 0000000000000003
RBP: 00000000006dbc50 R08: 00007fdbea223700 R09: 0000000000000000
R10: 00007fdbea223700 R11: 0000000000000246 R12: 00000000006dbc5c
R13: 6000030030626669 R14: 0000000000000000 R15: 0000000030626669

Allocated by task 7843:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:509
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3615
 kmalloc include/linux/slab.h:545 [inline]
 x25_link_device_up+0x46/0x3f0 net/x25/x25_link.c:249
 x25_device_event+0x116/0x2b0 net/x25/af_x25.c:242
 notifier_call_chain+0xc7/0x240 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739
 call_netdevice_notifiers_extack net/core/dev.c:1751 [inline]
 call_netdevice_notifiers net/core/dev.c:1765 [inline]
 __dev_notify_flags+0x121/0x2c0 net/core/dev.c:7605
 dev_change_flags+0x10d/0x170 net/core/dev.c:7643
 dev_ifsioc+0x2b0/0x940 net/core/dev_ioctl.c:237
 dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:488
 sock_do_ioctl+0x1bd/0x300 net/socket.c:995
 sock_ioctl+0x32b/0x610 net/socket.c:1096
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7865:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465
 __cache_free mm/slab.c:3494 [inline]
 kfree+0xcf/0x230 mm/slab.c:3811
 x25_neigh_put include/net/x25.h:253 [inline]
 x25_connect+0x8d8/0xde0 net/x25/af_x25.c:824
 __sys_connect+0x266/0x330 net/socket.c:1685
 __do_sys_connect net/socket.c:1696 [inline]
 __se_sys_connect net/socket.c:1693 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1693
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a030edc0
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 16 bytes inside of
 256-byte region [ffff8880a030edc0, ffff8880a030eec0)
The buggy address belongs to the page:
page:ffffea000280c380 count:1 mapcount:0 mapping:ffff88812c3f07c0 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002806788 ffffea00027f0188 ffff88812c3f07c0
raw: 0000000000000000 ffff8880a030e000 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+04babcefcd396fabec37@syzkaller.appspotmail.com
Cc: andrew hendry <andrew.hendry@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>