linux-stable.git/net/tls, branch v5.2

net/tls: fix page double free on TX cleanup

2019-06-24T14:20:45+00:00

With commit 94850257cf0f ("tls: Fix tls_device handling of partial records")
a new path was introduced to cleanup partial records during sk_proto_close.
This path does not handle the SW KTLS tx_list cleanup.

This is unnecessary though since the free_resources calls for both
SW and offload paths will cleanup a partial record.

The visible effect is the following warning, but this bug also causes
a page double free.

    WARNING: CPU: 7 PID: 4000 at net/core/stream.c:206 sk_stream_kill_queues+0x103/0x110
    RIP: 0010:sk_stream_kill_queues+0x103/0x110
    RSP: 0018:ffffb6df87e07bd0 EFLAGS: 00010206
    RAX: 0000000000000000 RBX: ffff8c21db4971c0 RCX: 0000000000000007
    RDX: ffffffffffffffa0 RSI: 000000000000001d RDI: ffff8c21db497270
    RBP: ffff8c21db497270 R08: ffff8c29f4748600 R09: 000000010020001a
    R10: ffffb6df87e07aa0 R11: ffffffff9a445600 R12: 0000000000000007
    R13: 0000000000000000 R14: ffff8c21f03f2900 R15: ffff8c21f03b8df0
    Call Trace:
     inet_csk_destroy_sock+0x55/0x100
     tcp_close+0x25d/0x400
     ? tcp_check_oom+0x120/0x120
     tls_sk_proto_close+0x127/0x1c0
     inet_release+0x3c/0x60
     __sock_release+0x3d/0xb0
     sock_close+0x11/0x20
     __fput+0xd8/0x210
     task_work_run+0x84/0xa0
     do_exit+0x2dc/0xb90
     ? release_sock+0x43/0x90
     do_group_exit+0x3a/0xa0
     get_signal+0x295/0x720
     do_signal+0x36/0x610
     ? SYSC_recvfrom+0x11d/0x130
     exit_to_usermode_loop+0x69/0xb0
     do_syscall_64+0x173/0x180
     entry_SYSCALL_64_after_hwframe+0x3d/0xa2
    RIP: 0033:0x7fe9b9abc10d
    RSP: 002b:00007fe9b19a1d48 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
    RAX: fffffffffffffe00 RBX: 0000000000000006 RCX: 00007fe9b9abc10d
    RDX: 0000000000000002 RSI: 0000000000000080 RDI: 00007fe948003430
    RBP: 00007fe948003410 R08: 00007fe948003430 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000246 R12: 00005603739d9080
    R13: 00007fe9b9ab9f90 R14: 00007fe948003430 R15: 0000000000000000

Fixes: 94850257cf0f ("tls: Fix tls_device handling of partial records")
Signed-off-by: Dirk van der Merwe 
Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

net: tls, correctly account for copied bytes with multiple sk_msgs

2019-06-12T18:04:35+00:00

tls_sw_do_sendpage needs to return the total number of bytes sent
regardless of how many sk_msgs are allocated. Unfortunately, copied
(the value we return up the stack) is zero'd before each new sk_msg
is allocated so we only return the copied size of the last sk_msg used.

The caller (splice, etc.) of sendpage will then believe only part
of its data was sent and send the missing chunks again. However,
because the data actually was sent the receiver will get multiple
copies of the same data.

To reproduce this do multiple sendfile calls with a length close to
the max record size. This will in turn call splice/sendpage, sendpage
may use multiple sk_msg in this case and then returns the incorrect
number of bytes. This will cause splice to resend creating duplicate
data on the receiver. Andre created a C program that can easily
generate this case so we will push a similar selftest for this to
bpf-next shortly.

The fix is to _not_ zero the copied field so that the total sent
bytes is returned.

Reported-by: Steinar H. Gunderson 
Reported-by: Andre Tomt 
Tested-by: Andre Tomt 
Fixes: d829e9c4112b ("tls: convert to generic sk_msg interface")
Signed-off-by: John Fastabend 
Signed-off-by: David S. Miller

net/tls: replace the sleeping lock around RX resync with a bit lock

2019-06-04T20:34:37+00:00

Commit 38030d7cb779 ("net/tls: avoid NULL-deref on resync during device removal")
tried to fix a potential NULL-dereference by taking the
context rwsem.  Unfortunately the RX resync may get called
from soft IRQ, so we can't use the rwsem to protect from
the device disappearing.  Because we are guaranteed there
can be only one resync at a time (it's called from strparser)
use a bit to indicate resync is busy and make device
removal wait for the bit to get cleared.

Note that there is a leftover "flags" field in struct
tls_context already.

Fixes: 4799ac81e52a ("tls: Add rx inline crypto offload")
Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

Revert "net/tls: avoid NULL-deref on resync during device removal"

2019-06-04T20:34:37+00:00

This reverts commit 38030d7cb77963ba84cdbe034806e2b81245339f.
Unfortunately the RX resync may get called from soft IRQ,
so we can't take the rwsem to protect from the device
disappearing.

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

net/tls: fix no wakeup on partial reads

2019-05-27T04:47:13+00:00

When tls_sw_recvmsg() partially copies a record it pops that
record from ctx->recv_pkt and places it on rx_list.

Next iteration of tls_sw_recvmsg() reads from rx_list via
process_rx_list() before it enters the decryption loop.
If there is no more records to be read tls_wait_data()
will put the process on the wait queue and got to sleep.
This is incorrect, because some data was already copied
in process_rx_list().

In case of RPC connections process may never get woken up,
because peer also simply blocks in read().

I think this may also fix a similar issue when BPF is at
play, because after __tcp_bpf_recvmsg() returns some data
we subtract it from len and use continue to restart the
loop, but len could have just reached 0, so again we'd
sleep unnecessarily. That's added by:
commit d3b18ad31f93 ("tls: add bpf support to sk_msg handling")

Fixes: 692d7b5d1f91 ("tls: Fix recvmsg() to be able to peek across multiple records")
Reported-by: David Beckett 
Signed-off-by: Jakub Kicinski 
Reviewed-by: Dirk van der Merwe 
Tested-by: David Beckett 
Signed-off-by: David S. Miller

net/tls: fix lowat calculation if some data came from previous record

2019-05-27T04:47:12+00:00

If some of the data came from the previous record, i.e. from
the rx_list it had already been decrypted, so it's not counted
towards the "decrypted" variable, but the "copied" variable.
Take that into account when checking lowat.

When calculating lowat target we need to pass the original len.
E.g. if lowat is at 80, len is 100 and we had 30 bytes on rx_list
target would currently be incorrectly calculated as 70, even though
we only need 50 more bytes to make up the 80.

Fixes: 692d7b5d1f91 ("tls: Fix recvmsg() to be able to peek across multiple records")
Signed-off-by: Jakub Kicinski 
Reviewed-by: Dirk van der Merwe 
Tested-by: David Beckett 
Signed-off-by: David S. Miller

net/tls: don't ignore netdev notifications if no TLS features

2019-05-22T19:21:44+00:00

On device surprise removal path (the notifier) we can't
bail just because the features are disabled.  They may
have been enabled during the lifetime of the device.
This bug leads to leaking netdev references and
use-after-frees if there are active connections while
device features are cleared.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Jakub Kicinski 
Reviewed-by: Dirk van der Merwe 
Signed-off-by: David S. Miller

net/tls: fix state removal with feature flags off

2019-05-22T19:21:44+00:00

TLS offload drivers shouldn't (and currently don't) block
the TLS offload feature changes based on whether there are
active offloaded connections or not.

This seems to be a good idea, because we want the admin to
be able to disable the TLS offload at any time, and there
is no clean way of disabling it for active connections
(TX side is quite problematic).  So if features are cleared
existing connections will stay offloaded until they close,
and new connections will not attempt offload to a given
device.

However, the offload state removal handling is currently
broken if feature flags get cleared while there are
active TLS offloads.

RX side will completely bail from cleanup, even on normal
remove path, leaving device state dangling, potentially
causing issues when the 5-tuple is reused.  It will also
fail to release the netdev reference.

Remove the RX-side warning message, in next release cycle
it should be printed when features are disabled, rather
than when connection dies, but for that we need a more
efficient method of finding connection of a given netdev
(a'la BPF offload code).

Fixes: 4799ac81e52a ("tls: Add rx inline crypto offload")
Signed-off-by: Jakub Kicinski 
Reviewed-by: Dirk van der Merwe 
Signed-off-by: David S. Miller

net/tls: avoid NULL-deref on resync during device removal

2019-05-22T19:21:44+00:00

When netdev with active kTLS sockets in unregistered
notifier callback walks the offloaded sockets and
cleans up offload state.  RX data may still be processed,
however, and if resync was requested prior to device
removal we would hit a NULL pointer dereference on
ctx->netdev use.

Make sure resync is under the device offload lock
and NULL-check the netdev pointer.

This should be safe, because the pointer is set to
NULL either in the netdev notifier (under said lock)
or when socket is completely dead and no resync can
happen.

The other access to ctx->netdev in tls_validate_xmit_skb()
does not dereference the pointer, it just checks it against
other device pointer, so it should be pretty safe (perhaps
we can add a READ_ONCE/WRITE_ONCE there, if paranoid).

Fixes: 4799ac81e52a ("tls: Add rx inline crypto offload")
Signed-off-by: Jakub Kicinski 
Reviewed-by: Dirk van der Merwe 
Signed-off-by: David S. Miller

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

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 
Signed-off-by: Greg Kroah-Hartman