linux-stable.git/net/rxrpc, branch linux-4.9.y Linux kernel stable tree rxrpc: Don't try to resend the request if we're receiving the reply 2022-06-14T14:52:33+00:00 David Howells dhowells@redhat.com 2022-05-21T08:03:11+00:00 46585a76949c61be303cd5b2d399e4f5c8186c8a [ Upstream commit 114af61f88fbe34d641b13922d098ffec4c1be1b ] rxrpc has a timer to trigger resending of unacked data packets in a call. This is not cancelled when a client call switches to the receive phase on the basis that most calls don't last long enough for it to ever expire. However, if it *does* expire after we've started to receive the reply, we shouldn't then go into trying to retransmit or pinging the server to find out if an ack got lost. Fix this by skipping the resend code if we're into receiving the reply to a client call. Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 114af61f88fbe34d641b13922d098ffec4c1be1b ]

rxrpc has a timer to trigger resending of unacked data packets in a call.
This is not cancelled when a client call switches to the receive phase on
the basis that most calls don't last long enough for it to ever expire.
However, if it *does* expire after we've started to receive the reply, we
shouldn't then go into trying to retransmit or pinging the server to find
out if an ack got lost.

Fix this by skipping the resend code if we're into receiving the reply to a
client call.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Fix listen() setting the bar too high for the prealloc rings 2022-06-14T14:52:33+00:00 David Howells dhowells@redhat.com 2022-05-21T08:03:04+00:00 61fb38cfbb1d54d3dafd0c25752f684b3cd00b32 [ Upstream commit 88e22159750b0d55793302eeed8ee603f5c1a95c ] AF_RXRPC's listen() handler lets you set the backlog up to 32 (if you bump up the sysctl), but whilst the preallocation circular buffers have 32 slots in them, one of them has to be a dead slot because we're using CIRC_CNT(). This means that listen(rxrpc_sock, 32) will cause an oops when the socket is closed because rxrpc_service_prealloc_one() allocated one too many calls and rxrpc_discard_prealloc() won't then be able to get rid of them because it'll think the ring is empty. rxrpc_release_calls_on_socket() then tries to abort them, but oopses because call->peer isn't yet set. Fix this by setting the maximum backlog to RXRPC_BACKLOG_MAX - 1 to match the ring capacity. BUG: kernel NULL pointer dereference, address: 0000000000000086 ... RIP: 0010:rxrpc_send_abort_packet+0x73/0x240 [rxrpc] Call Trace: <TASK> ? __wake_up_common_lock+0x7a/0x90 ? rxrpc_notify_socket+0x8e/0x140 [rxrpc] ? rxrpc_abort_call+0x4c/0x60 [rxrpc] rxrpc_release_calls_on_socket+0x107/0x1a0 [rxrpc] rxrpc_release+0xc9/0x1c0 [rxrpc] __sock_release+0x37/0xa0 sock_close+0x11/0x20 __fput+0x89/0x240 task_work_run+0x59/0x90 do_exit+0x319/0xaa0 Fixes: 00e907127e6f ("rxrpc: Preallocate peers, conns and calls for incoming service requests") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-afs@lists.infradead.org Link: https://lists.infradead.org/pipermail/linux-afs/2022-March/005079.html Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 88e22159750b0d55793302eeed8ee603f5c1a95c ]

AF_RXRPC's listen() handler lets you set the backlog up to 32 (if you bump
up the sysctl), but whilst the preallocation circular buffers have 32 slots
in them, one of them has to be a dead slot because we're using CIRC_CNT().

This means that listen(rxrpc_sock, 32) will cause an oops when the socket
is closed because rxrpc_service_prealloc_one() allocated one too many calls
and rxrpc_discard_prealloc() won't then be able to get rid of them because
it'll think the ring is empty.  rxrpc_release_calls_on_socket() then tries
to abort them, but oopses because call->peer isn't yet set.

Fix this by setting the maximum backlog to RXRPC_BACKLOG_MAX - 1 to match
the ring capacity.

 BUG: kernel NULL pointer dereference, address: 0000000000000086
 ...
 RIP: 0010:rxrpc_send_abort_packet+0x73/0x240 [rxrpc]
 Call Trace:
  <TASK>
  ? __wake_up_common_lock+0x7a/0x90
  ? rxrpc_notify_socket+0x8e/0x140 [rxrpc]
  ? rxrpc_abort_call+0x4c/0x60 [rxrpc]
  rxrpc_release_calls_on_socket+0x107/0x1a0 [rxrpc]
  rxrpc_release+0xc9/0x1c0 [rxrpc]
  __sock_release+0x37/0xa0
  sock_close+0x11/0x20
  __fput+0x89/0x240
  task_work_run+0x59/0x90
  do_exit+0x319/0xaa0

Fixes: 00e907127e6f ("rxrpc: Preallocate peers, conns and calls for incoming service requests")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org
Link: https://lists.infradead.org/pipermail/linux-afs/2022-March/005079.html
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Return an error to sendmsg if call failed 2022-06-14T14:52:30+00:00 David Howells dhowells@redhat.com 2022-05-21T07:45:41+00:00 019ed251b532c834a6d600d98da11c1028233bfd [ Upstream commit 4ba68c5192554876bd8c3afd904e3064d2915341 ] If at the end of rxrpc sendmsg() or rxrpc_kernel_send_data() the call that was being given data was aborted remotely or otherwise failed, return an error rather than returning the amount of data buffered for transmission. The call (presumably) did not complete, so there's not much point continuing with it. AF_RXRPC considers it "complete" and so will be unwilling to do anything else with it - and won't send a notification for it, deeming the return from sendmsg sufficient. Not returning an error causes afs to incorrectly handle a StoreData operation that gets interrupted by a change of address due to NAT reconfiguration. This doesn't normally affect most operations since their request parameters tend to fit into a single UDP packet and afs_make_call() returns before the server responds; StoreData is different as it involves transmission of a lot of data. This can be triggered on a client by doing something like: dd if=/dev/zero of=/afs/example.com/foo bs=1M count=512 at one prompt, and then changing the network address at another prompt, e.g.: ifconfig enp6s0 inet 192.168.6.2 && route add 192.168.6.1 dev enp6s0 Tracing packets on an Auristor fileserver looks something like: 192.168.6.1 -> 192.168.6.3 RX 107 ACK Idle Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 192.168.6.3 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(64538) (64538) 192.168.6.3 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(64538) (64538) 192.168.6.1 -> 192.168.6.3 RX 107 ACK Idle Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 <ARP exchange for 192.168.6.2> 192.168.6.2 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(0) (0) 192.168.6.2 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(0) (0) 192.168.6.1 -> 192.168.6.2 RX 107 ACK Exceeds Window Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 192.168.6.1 -> 192.168.6.2 RX 74 ABORT Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 192.168.6.1 -> 192.168.6.2 RX 74 ABORT Seq: 29321 Call: 4 Source Port: 7000 Destination Port: 7001 The Auristor fileserver logs code -453 (RXGEN_SS_UNMARSHAL), but the abort code received by kafs is -5 (RX_PROTOCOL_ERROR) as the rx layer sees the condition and generates an abort first and the unmarshal error is a consequence of that at the application layer. Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-December/004810.html # v1 Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4ba68c5192554876bd8c3afd904e3064d2915341 ]

If at the end of rxrpc sendmsg() or rxrpc_kernel_send_data() the call that
was being given data was aborted remotely or otherwise failed, return an
error rather than returning the amount of data buffered for transmission.

The call (presumably) did not complete, so there's not much point
continuing with it.  AF_RXRPC considers it "complete" and so will be
unwilling to do anything else with it - and won't send a notification for
it, deeming the return from sendmsg sufficient.

Not returning an error causes afs to incorrectly handle a StoreData
operation that gets interrupted by a change of address due to NAT
reconfiguration.

This doesn't normally affect most operations since their request parameters
tend to fit into a single UDP packet and afs_make_call() returns before the
server responds; StoreData is different as it involves transmission of a
lot of data.

This can be triggered on a client by doing something like:

	dd if=/dev/zero of=/afs/example.com/foo bs=1M count=512

at one prompt, and then changing the network address at another prompt,
e.g.:

	ifconfig enp6s0 inet 192.168.6.2 && route add 192.168.6.1 dev enp6s0

Tracing packets on an Auristor fileserver looks something like:

192.168.6.1 -> 192.168.6.3  RX 107 ACK Idle  Seq: 0  Call: 4  Source Port: 7000  Destination Port: 7001
192.168.6.3 -> 192.168.6.1  AFS (RX) 1482 FS Request: Unknown(64538) (64538)
192.168.6.3 -> 192.168.6.1  AFS (RX) 1482 FS Request: Unknown(64538) (64538)
192.168.6.1 -> 192.168.6.3  RX 107 ACK Idle  Seq: 0  Call: 4  Source Port: 7000  Destination Port: 7001
<ARP exchange for 192.168.6.2>
192.168.6.2 -> 192.168.6.1  AFS (RX) 1482 FS Request: Unknown(0) (0)
192.168.6.2 -> 192.168.6.1  AFS (RX) 1482 FS Request: Unknown(0) (0)
192.168.6.1 -> 192.168.6.2  RX 107 ACK Exceeds Window  Seq: 0  Call: 4  Source Port: 7000  Destination Port: 7001
192.168.6.1 -> 192.168.6.2  RX 74 ABORT  Seq: 0  Call: 4  Source Port: 7000  Destination Port: 7001
192.168.6.1 -> 192.168.6.2  RX 74 ABORT  Seq: 29321  Call: 4  Source Port: 7000  Destination Port: 7001

The Auristor fileserver logs code -453 (RXGEN_SS_UNMARSHAL), but the abort
code received by kafs is -5 (RX_PROTOCOL_ERROR) as the rx layer sees the
condition and generates an abort first and the unmarshal error is a
consequence of that at the application layer.

Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2021-December/004810.html # v1
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Fix handling of an unsupported token type in rxrpc_read() 2021-01-23T14:38:19+00:00 David Howells dhowells@redhat.com 2021-01-12T15:23:51+00:00 4a4ba4a0bd096a2e90bd0d0d1e6b238547906738 [ Upstream commit d52e419ac8b50c8bef41b398ed13528e75d7ad48 ] Clang static analysis reports the following: net/rxrpc/key.c:657:11: warning: Assigned value is garbage or undefined toksize = toksizes[tok++]; ^ ~~~~~~~~~~~~~~~ rxrpc_read() contains two consecutive loops. The first loop calculates the token sizes and stores the results in toksizes[] and the second one uses the array. When there is an error in identifying the token in the first loop, the token is skipped, no change is made to the toksizes[] array. When the same error happens in the second loop, the token is not skipped. This will cause the toksizes[] array to be out of step and will overrun past the calculated sizes. Fix this by making both loops log a message and return an error in this case. This should only happen if a new token type is incompletely implemented, so it should normally be impossible to trigger this. Fixes: 9a059cd5ca7d ("rxrpc: Downgrade the BUG() for unsupported token type in rxrpc_read()") Reported-by: Tom Rix <trix@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Tom Rix <trix@redhat.com> Link: https://lore.kernel.org/r/161046503122.2445787.16714129930607546635.stgit@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit d52e419ac8b50c8bef41b398ed13528e75d7ad48 ]

Clang static analysis reports the following:

net/rxrpc/key.c:657:11: warning: Assigned value is garbage or undefined
                toksize = toksizes[tok++];
                        ^ ~~~~~~~~~~~~~~~

rxrpc_read() contains two consecutive loops.  The first loop calculates the
token sizes and stores the results in toksizes[] and the second one uses
the array.  When there is an error in identifying the token in the first
loop, the token is skipped, no change is made to the toksizes[] array.
When the same error happens in the second loop, the token is not skipped.
This will cause the toksizes[] array to be out of step and will overrun
past the calculated sizes.

Fix this by making both loops log a message and return an error in this
case.  This should only happen if a new token type is incompletely
implemented, so it should normally be impossible to trigger this.

Fixes: 9a059cd5ca7d ("rxrpc: Downgrade the BUG() for unsupported token type in rxrpc_read()")
Reported-by: Tom Rix <trix@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/161046503122.2445787.16714129930607546635.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rxrpc: Fix server keyring leak 2020-10-14T07:48:17+00:00 David Howells dhowells@redhat.com 2020-10-02T13:04:51+00:00 2f2a503643ad8204be8f8f8e7fb7f227b5972e4a [ Upstream commit 38b1dc47a35ba14c3f4472138ea56d014c2d609b ] If someone calls setsockopt() twice to set a server key keyring, the first keyring is leaked. Fix it to return an error instead if the server key keyring is already set. Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 38b1dc47a35ba14c3f4472138ea56d014c2d609b ]

If someone calls setsockopt() twice to set a server key keyring, the first
keyring is leaked.

Fix it to return an error instead if the server key keyring is already set.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Fix some missing _bh annotations on locking conn->state_lock 2020-10-14T07:48:17+00:00 David Howells dhowells@redhat.com 2020-10-01T10:57:40+00:00 81f997b4b9f4527be45699224ec7f7ac4970cef4 [ Upstream commit fa1d113a0f96f9ab7e4fe4f8825753ba1e34a9d3 ] conn->state_lock may be taken in softirq mode, but a previous patch replaced an outer lock in the response-packet event handling code, and lost the _bh from that when doing so. Fix this by applying the _bh annotation to the state_lock locking. Fixes: a1399f8bb033 ("rxrpc: Call channels should have separate call number spaces") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit fa1d113a0f96f9ab7e4fe4f8825753ba1e34a9d3 ]

conn->state_lock may be taken in softirq mode, but a previous patch
replaced an outer lock in the response-packet event handling code, and lost
the _bh from that when doing so.

Fix this by applying the _bh annotation to the state_lock locking.

Fixes: a1399f8bb033 ("rxrpc: Call channels should have separate call number spaces")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Downgrade the BUG() for unsupported token type in rxrpc_read() 2020-10-14T07:48:17+00:00 David Howells dhowells@redhat.com 2020-09-08T21:09:04+00:00 90a4dcfd864ca1854ff32e7feab457e786877091 [ Upstream commit 9a059cd5ca7d9c5c4ca5a6e755cf72f230176b6a ] If rxrpc_read() (which allows KEYCTL_READ to read a key), sees a token of a type it doesn't recognise, it can BUG in a couple of places, which is unnecessary as it can easily get back to userspace. Fix this to print an error message instead. Fixes: 99455153d067 ("RxRPC: Parse security index 5 keys (Kerberos 5)") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9a059cd5ca7d9c5c4ca5a6e755cf72f230176b6a ]

If rxrpc_read() (which allows KEYCTL_READ to read a key), sees a token of a
type it doesn't recognise, it can BUG in a couple of places, which is
unnecessary as it can easily get back to userspace.

Fix this to print an error message instead.

Fixes: 99455153d067 ("RxRPC: Parse security index 5 keys (Kerberos 5)")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Fix rxkad token xdr encoding 2020-10-14T07:48:16+00:00 Marc Dionne marc.dionne@auristor.com 2020-09-04T17:01:24+00:00 922888326eb52239f3a76bbb7aa3f1fb952c0076 [ Upstream commit 56305118e05b2db8d0395bba640ac9a3aee92624 ] The session key should be encoded with just the 8 data bytes and no length; ENCODE_DATA precedes it with a 4 byte length, which confuses some existing tools that try to parse this format. Add an ENCODE_BYTES macro that does not include a length, and use it for the key. Also adjust the expected length. Note that commit 774521f353e1d ("rxrpc: Fix an assertion in rxrpc_read()") had fixed a BUG by changing the length rather than fixing the encoding. The original length was correct. Fixes: 99455153d067 ("RxRPC: Parse security index 5 keys (Kerberos 5)") Signed-off-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 56305118e05b2db8d0395bba640ac9a3aee92624 ]

The session key should be encoded with just the 8 data bytes and
no length; ENCODE_DATA precedes it with a 4 byte length, which
confuses some existing tools that try to parse this format.

Add an ENCODE_BYTES macro that does not include a length, and use
it for the key.  Also adjust the expected length.

Note that commit 774521f353e1d ("rxrpc: Fix an assertion in
rxrpc_read()") had fixed a BUG by changing the length rather than
fixing the encoding.  The original length was correct.

Fixes: 99455153d067 ("RxRPC: Parse security index 5 keys (Kerberos 5)")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rxrpc: Fix sendmsg() returning EPIPE due to recvmsg() returning ENODATA 2020-07-31T14:44:06+00:00 David Howells dhowells@redhat.com 2020-07-20T11:41:46+00:00 3a74e2808eba19e42249f183e6a12450d3f00d54 [ Upstream commit 639f181f0ee20d3249dbc55f740f0167267180f0 ] rxrpc_sendmsg() returns EPIPE if there's an outstanding error, such as if rxrpc_recvmsg() indicating ENODATA if there's nothing for it to read. Change rxrpc_recvmsg() to return EAGAIN instead if there's nothing to read as this particular error doesn't get stored in ->sk_err by the networking core. Also change rxrpc_sendmsg() so that it doesn't fail with delayed receive errors (there's no way for it to report which call, if any, the error was caused by). Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 639f181f0ee20d3249dbc55f740f0167267180f0 ]

rxrpc_sendmsg() returns EPIPE if there's an outstanding error, such as if
rxrpc_recvmsg() indicating ENODATA if there's nothing for it to read.

Change rxrpc_recvmsg() to return EAGAIN instead if there's nothing to read
as this particular error doesn't get stored in ->sk_err by the networking
core.

Also change rxrpc_sendmsg() so that it doesn't fail with delayed receive
errors (there's no way for it to report which call, if any, the error was
caused by).

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rxrpc: Fix notification call on completion of discarded calls 2020-06-30T19:38:38+00:00 David Howells dhowells@redhat.com 2020-06-19T22:38:16+00:00 5e43d1cbe3b91e439c1eab631a0c9380b37a6d20 [ Upstream commit 0041cd5a50442db6e456b145892a0eaf2dff061f ] When preallocated service calls are being discarded, they're passed to ->discard_new_call() to have the caller clean up any attached higher-layer preallocated pieces before being marked completed. However, the act of marking them completed now invokes the call's notification function - which causes a problem because that function might assume that the previously freed pieces of memory are still there. Fix this by setting a dummy notification function on the socket after calling ->discard_new_call(). This results in the following kasan message when the kafs module is removed. ================================================================== BUG: KASAN: use-after-free in afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707 Write of size 1 at addr ffff8880946c39e4 by task kworker/u4:1/21 CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707 rxrpc_notify_socket+0x1db/0x5d0 net/rxrpc/recvmsg.c:40 __rxrpc_set_call_completion.part.0+0x172/0x410 net/rxrpc/recvmsg.c:76 __rxrpc_call_completed net/rxrpc/recvmsg.c:112 [inline] rxrpc_call_completed+0xca/0xf0 net/rxrpc/recvmsg.c:111 rxrpc_discard_prealloc+0x781/0xab0 net/rxrpc/call_accept.c:233 rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603 process_one_work+0x965/0x1690 kernel/workqueue.c:2269 worker_thread+0x96/0xe10 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Allocated by task 6820: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc mm/kasan/common.c:494 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] afs_alloc_call+0x55/0x630 fs/afs/rxrpc.c:141 afs_charge_preallocation+0xe9/0x2d0 fs/afs/rxrpc.c:757 afs_open_socket+0x292/0x360 fs/afs/rxrpc.c:92 afs_net_init+0xa6c/0xe30 fs/afs/main.c:125 ops_init+0xaf/0x420 net/core/net_namespace.c:151 setup_net+0x2de/0x860 net/core/net_namespace.c:341 copy_net_ns+0x293/0x590 net/core/net_namespace.c:482 create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231 ksys_unshare+0x43d/0x8e0 kernel/fork.c:2983 __do_sys_unshare kernel/fork.c:3051 [inline] __se_sys_unshare kernel/fork.c:3049 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3049 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 21: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 afs_put_call+0x585/0xa40 fs/afs/rxrpc.c:190 rxrpc_discard_prealloc+0x764/0xab0 net/rxrpc/call_accept.c:230 rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603 process_one_work+0x965/0x1690 kernel/workqueue.c:2269 worker_thread+0x96/0xe10 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 The buggy address belongs to the object at ffff8880946c3800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 484 bytes inside of 1024-byte region [ffff8880946c3800, ffff8880946c3c00) The buggy address belongs to the page: page:ffffea000251b0c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002546508 ffffea00024fa248 ffff8880aa000c40 raw: 0000000000000000 ffff8880946c3000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880946c3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880946c3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880946c3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880946c3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880946c3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Reported-by: syzbot+d3eccef36ddbd02713e9@syzkaller.appspotmail.com Fixes: 5ac0d62226a0 ("rxrpc: Fix missing notification") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 0041cd5a50442db6e456b145892a0eaf2dff061f ]

When preallocated service calls are being discarded, they're passed to
->discard_new_call() to have the caller clean up any attached higher-layer
preallocated pieces before being marked completed.  However, the act of
marking them completed now invokes the call's notification function - which
causes a problem because that function might assume that the previously
freed pieces of memory are still there.

Fix this by setting a dummy notification function on the socket after
calling ->discard_new_call().

This results in the following kasan message when the kafs module is
removed.

==================================================================
BUG: KASAN: use-after-free in afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707
Write of size 1 at addr ffff8880946c39e4 by task kworker/u4:1/21

CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707
 rxrpc_notify_socket+0x1db/0x5d0 net/rxrpc/recvmsg.c:40
 __rxrpc_set_call_completion.part.0+0x172/0x410 net/rxrpc/recvmsg.c:76
 __rxrpc_call_completed net/rxrpc/recvmsg.c:112 [inline]
 rxrpc_call_completed+0xca/0xf0 net/rxrpc/recvmsg.c:111
 rxrpc_discard_prealloc+0x781/0xab0 net/rxrpc/call_accept.c:233
 rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245
 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186
 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603
 process_one_work+0x965/0x1690 kernel/workqueue.c:2269
 worker_thread+0x96/0xe10 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 6820:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc mm/kasan/common.c:494 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 afs_alloc_call+0x55/0x630 fs/afs/rxrpc.c:141
 afs_charge_preallocation+0xe9/0x2d0 fs/afs/rxrpc.c:757
 afs_open_socket+0x292/0x360 fs/afs/rxrpc.c:92
 afs_net_init+0xa6c/0xe30 fs/afs/main.c:125
 ops_init+0xaf/0x420 net/core/net_namespace.c:151
 setup_net+0x2de/0x860 net/core/net_namespace.c:341
 copy_net_ns+0x293/0x590 net/core/net_namespace.c:482
 create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x43d/0x8e0 kernel/fork.c:2983
 __do_sys_unshare kernel/fork.c:3051 [inline]
 __se_sys_unshare kernel/fork.c:3049 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3049
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 21:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 afs_put_call+0x585/0xa40 fs/afs/rxrpc.c:190
 rxrpc_discard_prealloc+0x764/0xab0 net/rxrpc/call_accept.c:230
 rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245
 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186
 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603
 process_one_work+0x965/0x1690 kernel/workqueue.c:2269
 worker_thread+0x96/0xe10 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff8880946c3800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 484 bytes inside of
 1024-byte region [ffff8880946c3800, ffff8880946c3c00)
The buggy address belongs to the page:
page:ffffea000251b0c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002546508 ffffea00024fa248 ffff8880aa000c40
raw: 0000000000000000 ffff8880946c3000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880946c3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880946c3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880946c3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff8880946c3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880946c3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Reported-by: syzbot+d3eccef36ddbd02713e9@syzkaller.appspotmail.com
Fixes: 5ac0d62226a0 ("rxrpc: Fix missing notification")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>