Bluetooth: fix set_ecdh_privkey() prototype

gcc-11 points out that the declaration does not match the definition:

net/bluetooth/ecdh_helper.c:122:55: error: argument 2 of type ‘const u8[32]’ {aka ‘const unsigned char[32]’} with mismatched bound [-Werror=array-parameter=]
122 | int set_ecdh_privkey(struct crypto_kpp *tfm, const u8 private_key[32])
| ~~~~~~~~~^~~~~~~~~~~~~~~
In file included from net/bluetooth/ecdh_helper.c:23:
net/bluetooth/ecdh_helper.h:28:56: note: previously declared as ‘const u8 *’ {aka ‘const unsigned char *’}
28 | int set_ecdh_privkey(struct crypto_kpp *tfm, const u8 *private_key);
| ~~~~~~~~~~^~~~~~~~~~~

Change the declaration to contain the size of the array, rather than
just a pointer.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Fix misc new gcc warnings

It seems like Fedora 34 ends up enabling a few new gcc warnings, notably
"-Wstringop-overread" and "-Warray-parameter".

Both of them cause what seem to be valid warnings in the kernel, where
we have array size mismatches in function arguments (that are no longer
just silently converted to a pointer to element, but actually checked).

This fixes most of the trivial ones, by making the function declaration
match the function definition, and in the case of intel_pm.c, removing
the over-specified array size from the argument declaration.

At least one 'stringop-overread' warning remains in the i915 driver, but
that one doesn't have the same obvious trivial fix, and may or may not
actually be indicative of a bug.

[ It was a mistake to upgrade one of my machines to Fedora 34 while
being busy with the merge window, but if this is the extent of the
compiler upgrade problems, things are better than usual - Linus ]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Bluetooth: let the crypto subsystem generate the ecc privkey

That Bluetooth SMP knows about the private key is pointless, since the
detection of debug key usage is actually via the public key portion.
With this patch, the Bluetooth SMP will stop keeping a copy of the
ecdh private key and will let the crypto subsystem to generate and
handle the ecdh private key, potentially benefiting of hardware
ecc private key generation and retention.

The loop that tries to generate a correct private key is now removed and
we trust the crypto subsystem to generate a correct private key. This
backup logic should be done in crypto, if really needed.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: ecdh_helper - reveal error codes

ecdh_helper functions were hiding the error codes and chose to return
the return value of an relational operator, "==". Remove the unnecessary
query and reveal the error codes.

While updating the return values, code in a way that compilers will
warn in case of uninitialized err.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: move ecdh allocation outside of ecdh_helper

Before this change, a new crypto tfm was allocated, each time,
for both key generation and shared secret computation.

Allocate a single tfm for both cases.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: convert smp and selftest to crypto kpp API

* Convert both smp and selftest to crypto kpp API
* Remove module ecc as no more required
* Add ecdh_helper functions for wrapping kpp async calls

This patch has been tested *only* with selftest, which is called on
module loading.

Signed-off-by: Salvatore Benedetto <salvatore.benedetto@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>