linux-stable.git/include/net/tls.h, branch linux-5.4.y

net/tls: Fix flipped sign in tls_err_abort() calls

2021-11-02T18:46:12+00:00

commit da353fac65fede6b8b4cfe207f0d9408e3121105 upstream.

sk->sk_err appears to expect a positive value, a convention that ktls
doesn't always follow and that leads to memory corruption in other code.
For instance,

    [kworker]
    tls_encrypt_done(..., err=)
      tls_err_abort(.., err)
        sk->sk_err = err;

    [task]
    splice_from_pipe_feed
      ...
        tls_sw_do_sendpage
          if (sk->sk_err) {
            ret = -sk->sk_err;  // ret is positive

    splice_from_pipe_feed (continued)
      ret = actor(...)  // ret is still positive and interpreted as bytes
                        // written, resulting in underflow of buf->len and
                        // sd->len, leading to huge buf->offset and bogus
                        // addresses computed in later calls to actor()

Fix all tls_err_abort() callers to pass a negative error code
consistently and centralize the error-prone sign flip there, throwing in
a warning to catch future misuse and uninlining the function so it
really does only warn once.

Cc: stable@vger.kernel.org
Fixes: c46234ebb4d1e ("tls: RX path for ktls")
Reported-by: syzbot+b187b77c8474f9648fae@syzkaller.appspotmail.com
Signed-off-by: Daniel Jordan 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/tls: Protect from calling tls_dev_del for TLS RX twice

2020-12-08T09:40:23+00:00

[ Upstream commit 025cc2fb6a4e84e9a0552c0017dcd1c24b7ac7da ]

tls_device_offload_cleanup_rx doesn't clear tls_ctx->netdev after
calling tls_dev_del if TLX TX offload is also enabled. Clearing
tls_ctx->netdev gets postponed until tls_device_gc_task. It leaves a
time frame when tls_device_down may get called and call tls_dev_del for
RX one extra time, confusing the driver, which may lead to a crash.

This patch corrects this racy behavior by adding a flag to prevent
tls_device_down from calling tls_dev_del the second time.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Maxim Mikityanskiy 
Signed-off-by: Saeed Mahameed 
Link: https://lore.kernel.org/r/20201125221810.69870-1-saeedm@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

bpf: Fix running sk_skb program types with ktls

2020-06-22T07:31:12+00:00

[ Upstream commit e91de6afa81c10e9f855c5695eb9a53168d96b73 ]

KTLS uses a stream parser to collect TLS messages and send them to
the upper layer tls receive handler. This ensures the tls receiver
has a full TLS header to parse when it is run. However, when a
socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS
is enabled we end up with two stream parsers running on the same
socket.

The result is both try to run on the same socket. First the KTLS
stream parser runs and calls read_sock() which will tcp_read_sock
which in turn calls tcp_rcv_skb(). This dequeues the skb from the
sk_receive_queue. When this is done KTLS code then data_ready()
callback which because we stacked KTLS on top of the bpf stream
verdict program has been replaced with sk_psock_start_strp(). This
will in turn kick the stream parser again and eventually do the
same thing KTLS did above calling into tcp_rcv_skb() and dequeuing
a skb from the sk_receive_queue.

At this point the data stream is broke. Part of the stream was
handled by the KTLS side some other bytes may have been handled
by the BPF side. Generally this results in either missing data
or more likely a "Bad Message" complaint from the kTLS receive
handler as the BPF program steals some bytes meant to be in a
TLS header and/or the TLS header length is no longer correct.

We've already broke the idealized model where we can stack ULPs
in any order with generic callbacks on the TX side to handle this.
So in this patch we do the same thing but for RX side. We add
a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict
program is running and add a tls_sw_has_ctx_rx() helper so BPF
side can learn there is a TLS ULP on the socket.

Then on BPF side we omit calling our stream parser to avoid
breaking the data stream for the KTLS receiver. Then on the
KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS
receiver is done with the packet but before it posts the
msg to userspace. This gives us symmetry between the TX and
RX halfs and IMO makes it usable again. On the TX side we
process packets in this order BPF -> TLS -> TCP and on
the receive side in the reverse order TCP -> TLS -> BPF.

Discovered while testing OpenSSL 3.0 Alpha2.0 release.

Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface")
Signed-off-by: John Fastabend
Signed-off-by: Alexei Starovoitov
Link: https://lore.kernel.org/bpf/159079361946.5745.605854335665044485.stgit@john-Precision-5820-Tower
Signed-off-by: Alexei Starovoitov
Signed-off-by: Sasha Levin

net/tls: fix race condition causing kernel panic

2020-06-03T06:21:01+00:00

[ Upstream commit 0cada33241d9de205522e3858b18e506ca5cce2c ]

tls_sw_recvmsg() and tls_decrypt_done() can be run concurrently.
// tls_sw_recvmsg()
	if (atomic_read(&ctx->decrypt_pending))
		crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
	else
		reinit_completion(&ctx->async_wait.completion);

//tls_decrypt_done()
  	pending = atomic_dec_return(&ctx->decrypt_pending);

  	if (!pending && READ_ONCE(ctx->async_notify))
  		complete(&ctx->async_wait.completion);

Consider the scenario tls_decrypt_done() is about to run complete()

	if (!pending && READ_ONCE(ctx->async_notify))

and tls_sw_recvmsg() reads decrypt_pending == 0, does reinit_completion(),
then tls_decrypt_done() runs complete(). This sequence of execution
results in wrong completion. Consequently, for next decrypt request,
it will not wait for completion, eventually on connection close, crypto
resources freed, there is no way to handle pending decrypt response.

This race condition can be avoided by having atomic_read() mutually
exclusive with atomic_dec_return(),complete().Intoduced spin lock to
ensure the mutual exclution.

Addressed similar problem in tx direction.

v1->v2:
- More readable commit message.
- Corrected the lock to fix new race scenario.
- Removed barrier which is not needed now.

Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance")
Signed-off-by: Vinay Kumar Yadav 
Reviewed-by: Jakub Kicinski 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/tls: use sg_next() to walk sg entries

2019-12-04T21:31:02+00:00

[ Upstream commit c5daa6cccdc2f94aca2c9b3fa5f94e4469997293 ]

Partially sent record cleanup path increments an SG entry
directly instead of using sg_next(). This should not be a
problem today, as encrypted messages should be always
allocated as arrays. But given this is a cleanup path it's
easy to miss was this ever to change. Use sg_next(), and
simplify the code.

Signed-off-by: Jakub Kicinski 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/tls: remove the dead inplace_crypto code

2019-12-04T21:31:02+00:00

[ Upstream commit 9e5ffed37df68d0ccfb2fdc528609e23a1e70ebe ]

Looks like when BPF support was added by commit d3b18ad31f93
("tls: add bpf support to sk_msg handling") and
commit d829e9c4112b ("tls: convert to generic sk_msg interface")
it broke/removed the support for in-place crypto as added by
commit 4e6d47206c32 ("tls: Add support for inplace records
encryption").

The inplace_crypto member of struct tls_rec is dead, inited
to zero, and sometimes set to zero again. It used to be
set to 1 when record was allocated, but the skmsg code doesn't
seem to have been written with the idea of in-place crypto
in mind.

Since non trivial effort is required to bring the feature back
and we don't really have the HW to measure the benefit just
remove the left over support for now to avoid confusing readers.

Signed-off-by: Jakub Kicinski 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/tls: enable sk_msg redirect to tls socket egress

2019-11-19T23:03:02+00:00

Bring back tls_sw_sendpage_locked. sk_msg redirection into a socket
with TLS_TX takes the following path:

  tcp_bpf_sendmsg_redir
    tcp_bpf_push_locked
      tcp_bpf_push
        kernel_sendpage_locked
          sock->ops->sendpage_locked

Also update the flags test in tls_sw_sendpage_locked to allow flag
MSG_NO_SHARED_FRAGS. bpf_tcp_sendmsg sets this.

Link: https://lore.kernel.org/netdev/CA+FuTSdaAawmZ2N8nfDDKu3XLpXBbMtcCT0q4FntDD2gn8ASUw@mail.gmail.com/T/#t
Link: https://github.com/wdebruij/kerneltools/commits/icept.2
Fixes: 0608c69c9a80 ("bpf: sk_msg, sock{map|hash} redirect through ULP")
Fixes: f3de19af0f5b ("Revert \"net/tls: remove unused function tls_sw_sendpage_locked\"")
Signed-off-by: Willem de Bruijn 
Acked-by: John Fastabend 
Signed-off-by: David S. Miller

net/tls: add a TX lock

2019-11-07T01:33:32+00:00

TLS TX needs to release and re-acquire the socket lock if send buffer
fills up.

TLS SW TX path currently depends on only allowing one thread to enter
the function by the abuse of sk_write_pending. If another writer is
already waiting for memory no new ones are allowed in.

This has two problems:
- writers don't wake other threads up when they leave the kernel;
meaning that this scheme works for single extra thread (second
application thread or delayed work) because memory becoming
available will send a wake up request, but as Mallesham and
Pooja report with larger number of threads it leads to threads
being put to sleep indefinitely;
- the delayed work does not get _scheduled_ but it may _run_ when
other writers are present leading to crashes as writers don't
expect state to change under their feet (same records get pushed
and freed multiple times); it's hard to reliably bail from the
work, however, because the mere presence of a writer does not
guarantee that the writer will push pending records before exiting.

Ensuring wakeups always happen will make the code basically open
code a mutex. Just use a mutex.

The TLS HW TX path does not have any locking (not even the
sk_write_pending hack), yet it uses a per-socket sg_tx_data
array to push records.

Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance")
Reported-by: Mallesham Jatharakonda
Reported-by: Pooja Trivedi
Signed-off-by: Jakub Kicinski
Reviewed-by: Simon Horman
Signed-off-by: David S. Miller

net/tls: clean up the number of #ifdefs for CONFIG_TLS_DEVICE

2019-09-05T07:49:49+00:00

TLS code has a number of #ifdefs which make the code a little
harder to follow. Recent fixes removed the ifdef around the
TLS_HW define, so we can switch to the often used pattern
of defining tls_device functions as empty static inlines
in the header when CONFIG_TLS_DEVICE=n.

Signed-off-by: Jakub Kicinski 
Reviewed-by: John Hurley 
Reviewed-by: Dirk van der Merwe 
Acked-by: John Fastabend 
Signed-off-by: David S. Miller

net/tls: use the full sk_proto pointer

2019-09-05T07:49:49+00:00

Since we already have the pointer to the full original sk_proto
stored use that instead of storing all individual callback
pointers as well.

Signed-off-by: Jakub Kicinski 
Reviewed-by: John Hurley 
Reviewed-by: Dirk van der Merwe 
Acked-by: John Fastabend 
Signed-off-by: David S. Miller