linux-stable.git/net/rxrpc/input.c, branch v5.6

afs: Fix client call Rx-phase signal handling

2020-03-13T23:04:35+00:00

Fix the handling of signals in client rxrpc calls made by the afs
filesystem.  Ignore signals completely, leaving call abandonment or
connection loss to be detected by timeouts inside AF_RXRPC.

Allowing a filesystem call to be interrupted after the entire request has
been transmitted and an abort sent means that the server may or may not
have done the action - and we don't know.  It may even be worse than that
for older servers.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells

rxrpc: Fix insufficient receive notification generation

2020-01-30T21:50:41+00:00

In rxrpc_input_data(), rxrpc_notify_socket() is called if the base sequence
number of the packet is immediately following the hard-ack point at the end
of the function.  However, this isn't sufficient, since the recvmsg side
may have been advancing the window and then overrun the position in which
we're adding - at which point rx_hard_ack >= seq0 and no notification is
generated.

Fix this by always generating a notification at the end of the input
function.

Without this, a long call may stall, possibly indefinitely.

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells

rxrpc: Fix use-after-free in rxrpc_receive_data()

2020-01-27T09:56:30+00:00

The subpacket scanning loop in rxrpc_receive_data() references the
subpacket count in the private data part of the sk_buff in the loop
termination condition.  However, when the final subpacket is pasted into
the ring buffer, the function is no longer has a ref on the sk_buff and
should not be looking at sp->* any more.  This point is actually marked in
the code when skb is cleared (but sp is not - which is an error).

Fix this by caching sp->nr_subpackets in a local variable and using that
instead.

Also clear 'sp' to catch accesses after that point.

This can show up as an oops in rxrpc_get_skb() if sp->nr_subpackets gets
trashed by the sk_buff getting freed and reused in the meantime.

Fixes: e2de6c404898 ("rxrpc: Use info in skbuff instead of reparsing a jumbo packet")
Signed-off-by: David Howells 
Signed-off-by: David S. Miller

rxrpc: Unlock new call in rxrpc_new_incoming_call() rather than the caller

2019-12-20T16:20:48+00:00

Move the unlock and the ping transmission for a new incoming call into
rxrpc_new_incoming_call() rather than doing it in the caller.  This makes
it clearer to see what's going on.

Suggested-by: Peter Zijlstra 
Signed-off-by: David Howells 
Acked-by: Peter Zijlstra (Intel) 
cc: Ingo Molnar 
cc: Will Deacon 
cc: Davidlohr Bueso

rxrpc: Fix misplaced traceline

2019-09-04T22:24:58+00:00

There's a misplaced traceline in rxrpc_input_packet() which is looking at a
packet that just got released rather than the replacement packet.

Fix this by moving the traceline after the assignment that moves the new
packet pointer to the actual packet pointer.

Fixes: d0d5c0cd1e71 ("rxrpc: Use skb_unshare() rather than skb_cow_data()")
Reported-by: Hillf Danton 
Signed-off-by: David Howells 
Signed-off-by: David S. Miller

rxrpc: Use skb_unshare() rather than skb_cow_data()

2019-08-27T09:13:46+00:00

The in-place decryption routines in AF_RXRPC's rxkad security module
currently call skb_cow_data() to make sure the data isn't shared and that
the skb can be written over.  This has a problem, however, as the softirq
handler may be still holding a ref or the Rx ring may be holding multiple
refs when skb_cow_data() is called in rxkad_verify_packet() - and so
skb_shared() returns true and __pskb_pull_tail() dislikes that.  If this
occurs, something like the following report will be generated.

	kernel BUG at net/core/skbuff.c:1463!
	...
	RIP: 0010:pskb_expand_head+0x253/0x2b0
	...
	Call Trace:
	 __pskb_pull_tail+0x49/0x460
	 skb_cow_data+0x6f/0x300
	 rxkad_verify_packet+0x18b/0xb10 [rxrpc]
	 rxrpc_recvmsg_data.isra.11+0x4a8/0xa10 [rxrpc]
	 rxrpc_kernel_recv_data+0x126/0x240 [rxrpc]
	 afs_extract_data+0x51/0x2d0 [kafs]
	 afs_deliver_fs_fetch_data+0x188/0x400 [kafs]
	 afs_deliver_to_call+0xac/0x430 [kafs]
	 afs_wait_for_call_to_complete+0x22f/0x3d0 [kafs]
	 afs_make_call+0x282/0x3f0 [kafs]
	 afs_fs_fetch_data+0x164/0x300 [kafs]
	 afs_fetch_data+0x54/0x130 [kafs]
	 afs_readpages+0x20d/0x340 [kafs]
	 read_pages+0x66/0x180
	 __do_page_cache_readahead+0x188/0x1a0
	 ondemand_readahead+0x17d/0x2e0
	 generic_file_read_iter+0x740/0xc10
	 __vfs_read+0x145/0x1a0
	 vfs_read+0x8c/0x140
	 ksys_read+0x4a/0xb0
	 do_syscall_64+0x43/0xf0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by using skb_unshare() instead in the input path for DATA packets
that have a security index != 0.  Non-DATA packets don't need in-place
encryption and neither do unencrypted DATA packets.

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Reported-by: Julian Wollrath 
Signed-off-by: David Howells

rxrpc: Use the tx-phase skb flag to simplify tracing

2019-08-27T09:04:18+00:00

Use the previously-added transmit-phase skbuff private flag to simplify the
socket buffer tracing a bit.  Which phase the skbuff comes from can now be
divined from the skb rather than having to be guessed from the call state.

We can also reduce the number of rxrpc_skb_trace values by eliminating the
difference between Tx and Rx in the symbols.

Signed-off-by: David Howells

rxrpc: Pass the input handler's data skb reference to the Rx ring

2019-08-27T08:59:19+00:00

Pass the reference held on a DATA skb in the rxrpc input handler into the
Rx ring rather than getting an additional ref for this and then dropping
the original ref at the end.

Signed-off-by: David Howells

rxrpc: Use info in skbuff instead of reparsing a jumbo packet

2019-08-27T08:51:30+00:00

Use the information now cached in the skbuff private data to avoid the need
to reparse a jumbo packet.  We can find all the subpackets by dead
reckoning, so it's only necessary to note how many there are, whether the
last one is flagged as LAST_PACKET and whether any have the REQUEST_ACK
flag set.

This is necessary as once recvmsg() can see the packet, it can start
modifying it, such as doing in-place decryption.

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells

rxrpc: Improve jumbo packet counting

2019-08-27T08:48:37+00:00

Improve the information stored about jumbo packets so that we don't need to
reparse them so much later.

Signed-off-by: David Howells 
Reviewed-by: Jeffrey Altman