linux.git/net/rxrpc, branch v5.11

rxrpc: Fix clearance of Tx/Rx ring when releasing a call

2021-02-05T02:11:08+00:00

At the end of rxrpc_release_call(), rxrpc_cleanup_ring() is called to clear
the Rx/Tx skbuff ring, but this doesn't lock the ring whilst it's accessing
it.  Unfortunately, rxrpc_resend() might be trying to retransmit a packet
concurrently with this - and whilst it does lock the ring, this isn't
protection against rxrpc_cleanup_call().

Fix this by removing the call to rxrpc_cleanup_ring() from
rxrpc_release_call().  rxrpc_cleanup_ring() will be called again anyway
from rxrpc_cleanup_call().  The earlier call is just an optimisation to
recycle skbuffs more quickly.

Alternative solutions include rxrpc_release_call() could try to cancel the
work item or wait for it to complete or rxrpc_cleanup_ring() could lock
when accessing the ring (which would require a bh lock).

This can produce a report like the following:

  BUG: KASAN: use-after-free in rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372
  Read of size 4 at addr ffff888011606e04 by task kworker/0:0/5
  ...
  Workqueue: krxrpcd rxrpc_process_call
  Call Trace:
   ...
   kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
   rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372
   rxrpc_resend net/rxrpc/call_event.c:266 [inline]
   rxrpc_process_call+0x1634/0x1f60 net/rxrpc/call_event.c:412
   process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
   ...

  Allocated by task 2318:
   ...
   sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2348
   rxrpc_send_data+0xb51/0x2bf0 net/rxrpc/sendmsg.c:358
   rxrpc_do_sendmsg+0xc03/0x1350 net/rxrpc/sendmsg.c:744
   rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:560
   ...

  Freed by task 2318:
   ...
   kfree_skb+0x140/0x3f0 net/core/skbuff.c:704
   rxrpc_free_skb+0x11d/0x150 net/rxrpc/skbuff.c:78
   rxrpc_cleanup_ring net/rxrpc/call_object.c:485 [inline]
   rxrpc_release_call+0x5dd/0x860 net/rxrpc/call_object.c:552
   rxrpc_release_calls_on_socket+0x21c/0x300 net/rxrpc/call_object.c:579
   rxrpc_release_sock net/rxrpc/af_rxrpc.c:885 [inline]
   rxrpc_release+0x263/0x5a0 net/rxrpc/af_rxrpc.c:916
   __sock_release+0xcd/0x280 net/socket.c:597
   ...

  The buggy address belongs to the object at ffff888011606dc0
   which belongs to the cache skbuff_head_cache of size 232

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Reported-by: syzbot+174de899852504e4a74a@syzkaller.appspotmail.com
Reported-by: syzbot+3d1c772efafd3c38d007@syzkaller.appspotmail.com
Signed-off-by: David Howells 
cc: Hillf Danton 
Link: https://lore.kernel.org/r/161234207610.653119.5287360098400436976.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

rxrpc: Fix deadlock around release of dst cached on udp tunnel

2021-01-30T05:38:11+00:00

AF_RXRPC sockets use UDP ports in encap mode.  This causes socket and dst
from an incoming packet to get stolen and attached to the UDP socket from
whence it is leaked when that socket is closed.

When a network namespace is removed, the wait for dst records to be cleaned
up happens before the cleanup of the rxrpc and UDP socket, meaning that the
wait never finishes.

Fix this by moving the rxrpc (and, by dependence, the afs) private
per-network namespace registrations to the device group rather than subsys
group.  This allows cached rxrpc local endpoints to be cleared and their
UDP sockets closed before we try waiting for the dst records.

The symptom is that lines looking like the following:

	unregister_netdevice: waiting for lo to become free

get emitted at regular intervals after running something like the
referenced syzbot test.

Thanks to Vadim for tracking this down and work out the fix.

Reported-by: syzbot+df400f2f24a1677cd7e0@syzkaller.appspotmail.com
Reported-by: Vadim Fedorenko 
Fixes: 5271953cad31 ("rxrpc: Use the UDP encap_rcv hook")
Signed-off-by: David Howells 
Acked-by: Vadim Fedorenko 
Link: https://lore.kernel.org/r/161196443016.3868642.5577440140646403533.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

rxrpc: Fix memory leak in rxrpc_lookup_local

2021-01-28T21:12:14+00:00

Commit 9ebeddef58c4 ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
Then release ref in __rxrpc_put_peer and rxrpc_put_peer_locked.

	struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
	-               peer->local = local;
	+               peer->local = rxrpc_get_local(local);

rxrpc_discard_prealloc also need ref release in discarding.

syzbot report:
BUG: memory leak
unreferenced object 0xffff8881080ddc00 (size 256):
  comm "syz-executor339", pid 8462, jiffies 4294942238 (age 12.350s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 0a 00 00 00 00 c0 00 08 81 88 ff ff  ................
  backtrace:
    [<000000002b6e495f>] kmalloc include/linux/slab.h:552 [inline]
    [<000000002b6e495f>] kzalloc include/linux/slab.h:682 [inline]
    [<000000002b6e495f>] rxrpc_alloc_local net/rxrpc/local_object.c:79 [inline]
    [<000000002b6e495f>] rxrpc_lookup_local+0x1c1/0x760 net/rxrpc/local_object.c:244
    [<000000006b43a77b>] rxrpc_bind+0x174/0x240 net/rxrpc/af_rxrpc.c:149
    [<00000000fd447a55>] afs_open_socket+0xdb/0x200 fs/afs/rxrpc.c:64
    [<000000007fd8867c>] afs_net_init+0x2b4/0x340 fs/afs/main.c:126
    [<0000000063d80ec1>] ops_init+0x4e/0x190 net/core/net_namespace.c:152
    [<00000000073c5efa>] setup_net+0xde/0x2d0 net/core/net_namespace.c:342
    [<00000000a6744d5b>] copy_net_ns+0x19f/0x3e0 net/core/net_namespace.c:483
    [<0000000017d3aec3>] create_new_namespaces+0x199/0x4f0 kernel/nsproxy.c:110
    [<00000000186271ef>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
    [<000000002de7bac4>] ksys_unshare+0x2fe/0x5c0 kernel/fork.c:2957
    [<00000000349b12ba>] __do_sys_unshare kernel/fork.c:3025 [inline]
    [<00000000349b12ba>] __se_sys_unshare kernel/fork.c:3023 [inline]
    [<00000000349b12ba>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3023
    [<000000006d178ef7>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000637076d4>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 9ebeddef58c4 ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
Signed-off-by: Takeshi Misawa 
Reported-and-tested-by: syzbot+305326672fed51b205f7@syzkaller.appspotmail.com
Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/161183091692.3506637.3206605651502458810.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

rxrpc: Call state should be read with READ_ONCE() under some circumstances

2021-01-13T18:38:20+00:00

The call state may be changed at any time by the data-ready routine in
response to received packets, so if the call state is to be read and acted
upon several times in a function, READ_ONCE() must be used unless the call
state lock is held.

As it happens, we used READ_ONCE() to read the state a few lines above the
unmarked read in rxrpc_input_data(), so use that value rather than
re-reading it.

Fixes: a158bdd3247b ("rxrpc: Fix call timeouts")
Signed-off-by: Baptiste Lepers 
Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/161046715522.2450566.488819910256264150.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

rxrpc: Fix handling of an unsupported token type in rxrpc_read()

2021-01-13T18:38:00+00:00

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 
Signed-off-by: David Howells 
Reviewed-by: Tom Rix 
Link: https://lore.kernel.org/r/161046503122.2445787.16714129930607546635.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

net: rxrpc: convert comma to semicolon

2020-12-10T00:23:07+00:00

Replace a comma between expression statements by a semicolon.

Signed-off-by: Zheng Yongjun 
Reviewed-by: David Howells 
Signed-off-by: David S. Miller

rxrpc: Ask the security class how much space to allow in a packet

2020-11-23T19:53:11+00:00

Ask the security class how much header and trailer space to allow for when
allocating a packet, given how much data is remaining.

This will allow the rxgk security class to stick both a trailer in as well
as a header as appropriate in the future.

Signed-off-by: David Howells

rxrpc: rxkad: Don't use pskb_pull() to advance through the response packet

2020-11-23T18:09:30+00:00

In the rxkad security class, don't use pskb_pull() to advance through the
contents of the response packet.  There's no point, especially as the next
and last access to the skbuff still has to allow for the wire header in the
offset (which we didn't advance over).

Better to just add the displacement to the next offset.

Signed-off-by: David Howells

rxrpc: Organise connection security to use a union

2020-11-23T18:09:30+00:00

Organise the security information in the rxrpc_connection struct to use a
union to allow for different data for different security classes.

Signed-off-by: David Howells

rxrpc: Don't reserve security header in Tx DATA skbuff

2020-11-23T18:09:30+00:00

Insert the security header into the skbuff representing a DATA packet to be
transmitted rather than using skb_reserve() when the packet is allocated.
This makes it easier to apply crypto that spans the security header and the
data, particularly in the upcoming RxGK class where we have a common
encrypt-and-checksum function that is used in a number of circumstances.

Signed-off-by: David Howells