The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Convert platform_get_resource(), devm_ioremap_resource() to a single
call to devm_platform_get_and_ioremap_resource(), as this is exactly
what this function does.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Change blocksize to match the cfb(aes) generic implementation.
Signed-off-by: Ryan Wanner <Ryan.Wanner@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Avoiding detecting finely in-place operations with different
scatter lists. Copying the source data for decryption into rctx->lastc
regardless if the operation is in-place or not. This allows in-place
operations with different scatter lists.
This approach takes less resources than parsing both scatter lists to
check if they are equal.
Signed-off-by: Ryan Wanner <Ryan.Wanner@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
xts_check_key() is obsoleted by xts_verify_key(). Over time XTS crypto
drivers adopted the newer xts_verify_key() variant, but xts_check_key()
is still used by a number of drivers. Switch drivers to use the newer
xts_verify_key() and make a couple of cleanups. This allows us to drop
xts_check_key() completely and avoid redundancy.
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In order for the driver to be made aware of the capabilities of the SHA
and AES IP versions 0x600 , such as those present on the SAM9X60 SoC's,
add a corresponding switch case to the capability method of the respective
drivers. Without this, besides the capabilities not being correctly set,
the self tests may hang since the driver is endlessly waiting for a
completion to be set by a never occurring DMA interrupt handler.
Signed-off-by: Sergiu Moga <sergiu.moga@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The remove callback is only called after probe completed successfully.
In this case platform_set_drvdata() was called with a non-NULL argument
and so aes_dd is never NULL.
This is a preparation for making platform remove callbacks return void.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds support for hardware version of AES and SHA IPs
available on lan966x SoC.
Signed-off-by: Kavyasree Kotagiri <kavyasree.kotagiri@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case there were more requests from different tfms in the crypto
queue, only the context of the last initialized tfm was considered.
Fixes: ec2088b66f ("crypto: atmel-aes - Allocate aes dev at tfm init time")
Reported-by: Wolfgang Ocker <weo@reccoware.de>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Use swap() instead of implementing it in order to make code more clean.
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Allocate the atmel_aes_dev data at tfm init time, and not for
each crypt request.
There's a single AES IP per SoC, clarify that in the code.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
XTS is supported just for input lengths with data units of 128-bit blocks.
Add a fallback to software implementation when the last block is shorter
than 128 bits.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Set cra_blocksize to 1 to indicate OFB is a stream cipher.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
NIST 800-38A requires for the ECB, CBC, CFB, OFB and CTR modes that
the plaintext and ciphertext to have a positive integer length.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Input length smaller than block size does not make sense for XTS.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
NIST 800-38A requires for the ECB and CBC modes that the total number
of bits in the plaintext to be a multiple of the block cipher.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Convert cpu_to_be32(be32_to_cpu(E1) + E2) to use be32_add_cpu().
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
These drivers no longer need it as they are only probed via DT.
crypto_platform_data was allocated but unused, so remove it.
This is a follow up for:
commit 45a536e3a7 ("crypto: atmel-tdes - Retire dma_request_slave_channel_compat()")
commit db28512f48 ("crypto: atmel-sha - Retire dma_request_slave_channel_compat()")
commit 62f72cbdcf ("crypto: atmel-aes - Retire dma_request_slave_channel_compat()")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The CRYPTO_TFM_RES_* flags were apparently meant as a way to make the
->setkey() functions provide more information about errors. But these
flags weren't actually being used or tested, and in many cases they
weren't being set correctly anyway. So they've now been removed.
Also, if someone ever actually needs to start better distinguishing
->setkey() errors (which is somewhat unlikely, as this has been unneeded
for a long time), we'd be much better off just defining different return
values, like -EINVAL if the key is invalid for the algorithm vs.
-EKEYREJECTED if the key was rejected by a policy like "no weak keys".
That would be much simpler, less error-prone, and easier to test.
So just remove CRYPTO_TFM_RES_MASK and all the unneeded logic that
propagates these flags around.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The CRYPTO_TFM_RES_BAD_KEY_LEN flag was apparently meant as a way to
make the ->setkey() functions provide more information about errors.
However, no one actually checks for this flag, which makes it pointless.
Also, many algorithms fail to set this flag when given a bad length key.
Reviewing just the generic implementations, this is the case for
aes-fixed-time, cbcmac, echainiv, nhpoly1305, pcrypt, rfc3686, rfc4309,
rfc7539, rfc7539esp, salsa20, seqiv, and xcbc. But there are probably
many more in arch/*/crypto/ and drivers/crypto/.
Some algorithms can even set this flag when the key is the correct
length. For example, authenc and authencesn set it when the key payload
is malformed in any way (not just a bad length), the atmel-sha and ccree
drivers can set it if a memory allocation fails, and the chelsio driver
sets it for bad auth tag lengths, not just bad key lengths.
So even if someone actually wanted to start checking this flag (which
seems unlikely, since it's been unused for a long time), there would be
a lot of work needed to get it working correctly. But it would probably
be much better to go back to the drawing board and just define different
return values, like -EINVAL if the key is invalid for the algorithm vs.
-EKEYREJECTED if the key was rejected by a policy like "no weak keys".
That would be much simpler, less error-prone, and easier to test.
So just remove this flag.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The CTR transfer works in fragments of data of maximum 1 MByte because
of the 16 bit CTR counter embedded in the IP. Fix the CTR counter
overflow handling for messages larger than 1 MByte.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 781a08d974 ("crypto: atmel-aes - Fix counter overflow in CTR mode")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Do not update the IV in case of errors.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Even when deferring, we would like to know what caused it.
Update dev_warn to dev_err because if the DMA init fails,
the probe is stopped.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The 'direction' member of the dma_slave_config will be going away
as it duplicates the direction given in the prepare call.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
device_terminate_all() is used to abort all the pending and
ongoing transfers on the channel, it should be used just in the
error path.
Also, dmaengine_terminate_all() is deprecated and one should use
dmaengine_terminate_async() or dmaengine_terminate_sync(). The method
is not used in atomic context, use dmaengine_terminate_sync().
A secondary aspect of this patch is that it luckily avoids a deadlock
between atmel_aes and at_hdmac.c. While in tasklet with the lock held,
the dma controller invokes the client callback (dmaengine_terminate_all),
which tries to get the same lock. The at_hdmac fix would be to drop the
lock before invoking the client callback, a fix on at_hdmac will follow.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Move common alg type init to dedicated methods.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The req->iv of the skcipher_request is expected to contain the
last used IV. Update the req->iv for CTR mode.
Fixes: bd3c7b5c2a ("crypto: atmel - add Atmel AES driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
32 bit counter is not supported by neither of our AES IPs, all implement
a 16 bit block counter. Drop the 32 bit block counter logic.
Fixes: fcac83656a ("crypto: atmel-aes - fix the counter overflow in CTR mode")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Choose label names which say what the goto does and not from where
the goto was issued. This avoids adding superfluous labels like
"err_aes_buff".
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case the probe fails, the device/driver core takes care of printing
the driver name, device name and error code. Drop superfluous error message
at probe.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The driver no longer boots in legacy mode, only via DT. This makes the
dma_request_slave_channel_compat() redundant.
If ever the filter function would be executed it will return false as the
dma_slave is not really initialized.
Switch to use dma_request_chan() which would allow legacy boot if ever
needed again by configuring dma_slave_map for the DMA driver.
At the same time skip allocating memory for dma_slave as it is not used
anymore.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case of in-place decryption, the "lastc" buffer is used to copy
the last ciphertext block before the decryption of the message. It
is later used to update the req->iv of the skcipher_request.
"lastc" variable is not used to interact with the hardware, there
is no restriction to be of type "u32". Change the type of "lastc"
to "u8".
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Commit 7a7ffe65c8 ("crypto: skcipher - Add top-level skcipher interface")
dated 20 august 2015 introduced the new skcipher API which is supposed to
replace both blkcipher and ablkcipher. While all consumers of the API have
been converted long ago, some producers of the ablkcipher remain, forcing
us to keep the ablkcipher support routines alive, along with the matching
code to expose [a]blkciphers via the skcipher API.
So switch this driver to the skcipher API, allowing us to finally drop the
ablkcipher code in the near future.
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As it is if CONFIG_CRYPTO_DEV_ATMEL_AUTHENC is set to m it is in
effect disabled. This patch fixes it by using IS_ENABLED instead
of ifdef.
Fixes: 89a82ef87e ("crypto: atmel-authenc - add support to...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The driver uses a couple of buffers that seem to
be __be32 or __be64 fields, but declares them as
u32. This means there are a number of warnings
from sparse due to casting to/from __beXXX.
Fix these by changing the types of the buffer
and the associated variables.
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1059:28: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1059:28: expected unsigned int
drivers/crypto/atmel-aes.c:1059:28: got restricted __be32 [usertype]
drivers/crypto/atmel-aes.c:1550:28: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1550:28: expected unsigned int
drivers/crypto/atmel-aes.c:1550:28: got restricted __be32 [usertype]
drivers/crypto/atmel-aes.c:1561:39: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1561:39: expected unsigned long long [usertype]
drivers/crypto/atmel-aes.c:1561:39: got restricted __be64 [usertype]
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:15: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1599:15: expected unsigned int [usertype]
drivers/crypto/atmel-aes.c:1599:15: got restricted __be32 [usertype]
drivers/crypto/atmel-aes.c:1692:17: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1692:17: expected unsigned long long [usertype]
drivers/crypto/atmel-aes.c:1692:17: got restricted __be64 [usertype]
drivers/crypto/atmel-aes.c:1693:17: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1693:17: expected unsigned long long [usertype]
drivers/crypto/atmel-aes.c:1693:17: got restricted __be64 [usertype]
drivers/crypto/atmel-aes.c:1888:63: warning: incorrect type in initializer (different base types)
drivers/crypto/atmel-aes.c:1888:63: expected unsigned int
drivers/crypto/atmel-aes.c:1888:63: got restricted __le32 [usertype]
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
commit 394a9e0447 ("crypto: cfb - add missing 'chunksize' property")
adds a test vector where the input length is smaller than the IV length
(the second test vector). This revealed a NULL pointer dereference in
the atmel-aes driver, that is caused by passing an incorrect offset in
scatterwalk_map_and_copy() when atmel_aes_complete() is called.
Do not save the IV in req->info of ablkcipher_request (or equivalently
req->iv of skcipher_request) when req->nbytes < ivsize, because the IV
will not be further used.
While touching the code, modify the type of ivsize from int to
unsigned int, to comply with the return type of
crypto_ablkcipher_ivsize().
Fixes: 91308019ec ("crypto: atmel-aes - properly set IV after {en,de}crypt")
Cc: <stable@vger.kernel.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.
// <smpl>
@@
expression ret;
struct platform_device *E;
@@
ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);
if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>
While we're here, remove braces on if statements that only have one
statement (manually).
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <linux-crypto@vger.kernel.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The Atmel AES driver uses memzero_explicit on the keys on error, but the
variable zeroed isn't the right one because of a typo. Fix this by using
the right variable.
Fixes: 89a82ef87e ("crypto: atmel-authenc - add support to authenc(hmac(shaX), Y(aes)) modes")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Omit extra messages for a memory allocation failure in these functions.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pointer members of an object with static storage duration, if not
explicitly initialized, will be initialized to a NULL pointer.
The crypto API checks if these pointers are not NULL before using them,
therefore we can safely remove these empty functions.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When using the rfc4543(gcm(aes))) mode, the registers of the hardware
engine are not empty after use. If the engine is not reset before its
next use, the following results will be invalid.
Always reset the hardware engine.
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Certain cipher modes like CTS expect the IV (req->info) of
ablkcipher_request (or equivalently req->iv of skcipher_request) to
contain the last ciphertext block when the {en,de}crypt operation is done.
Fix this issue for the Atmel AES hardware engine. The tcrypt test
case for cts(cbc(aes)) is now correctly passed.
In the case of in-place decryption, copy the ciphertext in an
intermediate buffer before decryption.
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
irq would be set to -1 and then unused, if we failed to get IORESOURCE_MEM.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Rob Herring