linux-stable.git/net/x25, branch linux-4.4.y

net/x25: Return the correct errno code

2021-06-30T12:49:31+00:00

[ Upstream commit d7736958668c4facc15f421e622ffd718f5be80a ]

When kalloc or kmemdup failed, should return ENOMEM rather than ENOBUF.

Signed-off-by: Zheng Yongjun 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net/x25: prevent a couple of overflows

2020-12-11T12:36:43+00:00

[ Upstream commit 6ee50c8e262a0f0693dad264c3c99e30e6442a56 ]

The .x25_addr[] address comes from the user and is not necessarily
NUL terminated.  This leads to a couple problems.  The first problem is
that the strlen() in x25_bind() can read beyond the end of the buffer.

The second problem is more subtle and could result in memory corruption.
The call tree is:
  x25_connect()
  --> x25_write_internal()
      --> x25_addr_aton()

The .x25_addr[] buffers are copied to the "addresses" buffer from
x25_write_internal() so it will lead to stack corruption.

Verify that the strings are NUL terminated and return -EINVAL if they
are not.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: a9288525d2ae ("X25: Dont let x25_bind use addresses containing characters")
Reported-by: "kiyin(尹亮)" 
Signed-off-by: Dan Carpenter 
Acked-by: Martin Schiller 
Link: https://lore.kernel.org/r/X8ZeAKm8FnFpN//B@mwanda
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: x25: Increase refcnt of "struct x25_neigh" in x25_rx_call_request

2020-11-24T11:48:10+00:00

[ Upstream commit 4ee18c179e5e815fa5575e0d2db0c05795a804ee ]

The x25_disconnect function in x25_subr.c would decrease the refcount of
"x25->neighbour" (struct x25_neigh) and reset this pointer to NULL.

However, the x25_rx_call_request function in af_x25.c, which is called
when we receive a connection request, does not increase the refcount when
it assigns the pointer.

Fix this issue by increasing the refcount of "struct x25_neigh" in
x25_rx_call_request.

This patch fixes frequent kernel crashes when using AF_X25 sockets.

Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect")
Cc: Martin Schiller 
Signed-off-by: Xie He 
Link: https://lore.kernel.org/r/20201112103506.5875-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net/x25: Fix null-ptr-deref in x25_connect

2020-11-18T17:25:02+00:00

[ Upstream commit 361182308766a265b6c521879b34302617a8c209 ]

This fixes a regression for blocking connects introduced by commit
4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect").

The x25->neighbour is already set to "NULL" by x25_disconnect() now,
while a blocking connect is waiting in
x25_wait_for_connection_establishment(). Therefore x25->neighbour must
not be accessed here again and x25->state is also already set to
X25_STATE_0 by x25_disconnect().

Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect")
Signed-off-by: Martin Schiller 
Reviewed-by: Xie He 
Link: https://lore.kernel.org/r/20201109065449.9014-1-ms@dev.tdt.de
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net/x25: Fix null-ptr-deref in x25_disconnect

2020-08-21T08:52:53+00:00

commit 8999dc89497ab1c80d0718828e838c7cd5f6bffe upstream.

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

 #include 
 #include 

 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 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/x25: Fix x25_neigh refcnt leak when x25 disconnect

2020-08-21T08:52:53+00:00

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 
Signed-off-by: Xin Tan 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/x25: Fix x25_neigh refcnt leak when receiving frame

2020-05-02T15:20:33+00:00

[ 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 
Signed-off-by: Xin Tan 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/x25: fix nonblocking connect

2020-01-29T09:21:53+00:00

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 
Reported-by: syzbot+429c200ffc8772bfe070@syzkaller.appspotmail.com
Reported-by: syzbot+eec0c87f31a7c3b66f7b@syzkaller.appspotmail.com
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/x25: fix null_x25_address handling

2019-12-21T09:34:41+00:00

[ Upstream commit 06137619f061f498c2924f6543fa45b7d39f0501 ]

o x25_find_listener(): the compare for the null_x25_address was wrong.
   We have to check the x25_addr of the listener socket instead of the
   x25_addr of the incomming call.

 o x25_bind(): it was not possible to bind a socket to null_x25_address

Signed-off-by: Martin Schiller 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net/x25: fix called/calling length calculation in x25_parse_address_block

2019-12-21T09:34:40+00:00

[ Upstream commit d449ba3d581ed29f751a59792fdc775572c66904 ]

The length of the called and calling address was not calculated
correctly (BCD encoding).

Signed-off-by: Martin Schiller 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin