sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES)

Remove ->sendpage() and ->sendpage_locked(). sendmsg() with
MSG_SPLICE_PAGES should be used instead. This allows multiple pages and
multipage folios to be passed through.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # for net/can
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-afs@lists.infradead.org
cc: mptcp@lists.linux.dev
cc: rds-devel@oss.oracle.com
cc: tipc-discussion@lists.sourceforge.net
cc: virtualization@lists.linux-foundation.org
Link: https://lore.kernel.org/r/20230623225513.2732256-16-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

crypto: af_alg - add extra parameters for DRBG interface

Extend the user-space RNG interface:
1. Add entropy input via ALG_SET_DRBG_ENTROPY setsockopt option;
2. Add additional data input via sendmsg syscall.

This allows DRBG to be tested with test vectors, for example for the
purpose of CAVP testing, which otherwise isn't possible.

To prevent erroneous use of entropy input, it is hidden under
CRYPTO_USER_API_RNG_CAVP config option and requires CAP_SYS_ADMIN to
succeed.

Signed-off-by: Elena Petrova <lenaptr@google.com>
Acked-by: Stephan Müller <smueller@chronox.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

net: make ->{get,set}sockopt in proto_ops optional

Just check for a NULL method instead of wiring up
sock_no_{get,set}sockopt.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

crypto: algif_rng - remove redundant assignment to variable err

The variable err is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

net: remove sock_no_poll

Now that sock_poll handles a NULL ->poll or ->poll_mask there is no need
for a stub.

Signed-off-by: Christoph Hellwig <hch@lst.de>

crypto: algif_rng - Remove obsolete const-removal cast

Now that crypto_rng_reset takes a const argument, we no longer
need to cast away the const qualifier.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: algif_rng - zeroize buffer with random data

Due to the change to RNGs to always return zero in success case, the RNG
interface must zeroize the buffer with the length provided by the
caller.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

net: Remove iocb argument from sendmsg and recvmsg

After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.

Cc: Christoph Hellwig <hch@lst.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

crypto: algif_rng - fix sparse non static symbol warning

Fixes the following sparse warnings:

crypto/algif_rng.c:185:13: warning:
symbol 'rng_exit' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Stephan Mueller <smueller@chronox.de>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: algif_rng - add random number generator support

This patch adds the random number generator support for AF_ALG.

A random number generator's purpose is to generate data without
requiring the caller to provide any data. Therefore, the AF_ALG
interface handler for RNGs only implements a callback handler for
recvmsg.

The following parameters provided with a recvmsg are processed by the
RNG callback handler:

* sock - to resolve the RNG context data structure accessing the
RNG instance private to the socket

* len - this parameter allows userspace callers to specify how
many random bytes the RNG shall produce and return. As the
kernel context for the RNG allocates a buffer of 128 bytes to
store random numbers before copying them to userspace, the len
parameter is checked that it is not larger than 128. If a
caller wants more random numbers, a new request for recvmsg
shall be made.

The size of 128 bytes is chose because of the following considerations:

* to increase the memory footprint of the kernel too much (note,
that would be 128 bytes per open socket)

* 128 is divisible by any typical cryptographic block size an
RNG may have

* A request for random numbers typically only shall supply small
amount of data like for keys or IVs that should only require
one invocation of the recvmsg function.

Note, during instantiation of the RNG, the code checks whether the RNG
implementation requires seeding. If so, the RNG is seeded with output
from get_random_bytes.

A fully working example using all aspects of the RNG interface is
provided at http://www.chronox.de/libkcapi.html

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>