linux/include/crypto/algapi.h, branch v5.9

crypto: algapi - introduce the flag CRYPTO_ALG_ALLOCATES_MEMORY

2020-07-16T11:49:09Z

Introduce a new algorithm flag CRYPTO_ALG_ALLOCATES_MEMORY. If this flag is set, then the driver allocates memory in its request routine. Such drivers are not suitable for disk encryption because GFP_ATOMIC allocation can fail anytime (causing random I/O errors) and GFP_KERNEL allocation can recurse into the block layer, causing a deadlock. For now, this flag is only implemented for some algorithm types. We also assume some usage constraints for it to be meaningful, since there are lots of edge cases the crypto API allows (e.g., misaligned or fragmented scatterlists) that mean that nearly any crypto algorithm can allocate memory in some case. See the comment for details. Also add this flag to CRYPTO_ALG_INHERITED_FLAGS so that when a template is instantiated, this flag is set on the template instance if it is set on any algorithm the instance uses. Based on a patch by Mikulas Patocka (https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com). Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: algapi - add NEED_FALLBACK to INHERITED_FLAGS

2020-07-16T11:49:08Z

CRYPTO_ALG_NEED_FALLBACK is handled inconsistently. When it's requested to be clear, some templates propagate that request to child algorithms, while others don't. It's apparently desired for NEED_FALLBACK to be propagated, to avoid deadlocks where a module tries to load itself while it's being initialized, and to avoid unnecessarily complex fallback chains where we have e.g. cbc-aes-$driver falling back to cbc(aes-$driver) where aes-$driver itself falls back to aes-generic, instead of cbc-aes-$driver simply falling back to cbc(aes-generic). There have been a number of fixes to this effect: commit 89027579bc6c ("crypto: xts - Propagate NEED_FALLBACK bit") commit d2c2a85cfe82 ("crypto: ctr - Propagate NEED_FALLBACK bit") commit e6c2e65c70a6 ("crypto: cbc - Propagate NEED_FALLBACK bit") But it seems that other templates can have the same problems too. To avoid this whack-a-mole, just add NEED_FALLBACK to INHERITED_FLAGS so that it's always inherited. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: algapi - use common mechanism for inheriting flags

2020-07-16T11:49:08Z

The flag CRYPTO_ALG_ASYNC is "inherited" in the sense that when a template is instantiated, the template will have CRYPTO_ALG_ASYNC set if any of the algorithms it uses has CRYPTO_ALG_ASYNC set. We'd like to add a second flag (CRYPTO_ALG_ALLOCATES_MEMORY) that gets "inherited" in the same way. This is difficult because the handling of CRYPTO_ALG_ASYNC is hardcoded everywhere. Address this by: - Add CRYPTO_ALG_INHERITED_FLAGS, which contains the set of flags that have these inheritance semantics. - Add crypto_algt_inherited_mask(), for use by template ->create() methods. It returns any of these flags that the user asked to be unset and thus must be passed in the 'mask' to crypto_grab_*(). - Also modify crypto_check_attr_type() to handle computing the 'mask' so that most templates can just use this. - Make crypto_grab_*() propagate these flags to the template instance being created so that templates don't have to do this themselves. Make crypto/simd.c propagate these flags too, since it "wraps" another algorithm, similar to a template. Based on a patch by Mikulas Patocka (https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com). Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: algapi - create function to add request in front of queue

2020-05-08T05:30:40Z

Add crypto_enqueue_request_head function that enqueues a request in front of queue. This will be used in crypto-engine, on error path. In case a request was not executed by hardware, enqueue it back in front of queue (to keep the order of requests). Signed-off-by: Iuliana Prodan Signed-off-by: Herbert Xu

crypto: algapi - remove crypto_template::{alloc,free}()

2020-01-09T03:30:58Z

Now that all templates provide a ->create() method which creates an instance, installs a strongly-typed ->free() method directly to it, and registers it, the older ->alloc() and ->free() methods in 'struct crypto_template' are no longer used. Remove them. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: algapi - fold crypto_init_spawn() into crypto_grab_spawn()

2020-01-09T03:30:57Z

Now that crypto_init_spawn() is only called by crypto_grab_spawn(), simplify things by moving its functionality into crypto_grab_spawn(). In the process of doing this, also be more consistent about when the spawn and instance are updated, and remove the crypto_spawn::dropref flag since now it's always set. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: algapi - remove obsoleted instance creation helpers

2020-01-09T03:30:57Z

Remove lots of helper functions that were previously used for instantiating crypto templates, but are now unused: - crypto_get_attr_alg() and similar functions looked up an inner algorithm directly from a template parameter. These were replaced with getting the algorithm's name, then calling crypto_grab_*(). - crypto_init_spawn2() and similar functions initialized a spawn, given an algorithm. Similarly, these were replaced with crypto_grab_*(). - crypto_alloc_instance() and similar functions allocated an instance with a single spawn, given the inner algorithm. These aren't useful anymore since crypto_grab_*() need the instance allocated first. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: cipher - make crypto_spawn_cipher() take a crypto_cipher_spawn

2020-01-09T03:30:57Z

Now that all users of single-block cipher spawns have been converted to use 'struct crypto_cipher_spawn' rather than the less specifically typed 'struct crypto_spawn', make crypto_spawn_cipher() take a pointer to a 'struct crypto_cipher_spawn' rather than a 'struct crypto_spawn'. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: cipher - introduce crypto_cipher_spawn and crypto_grab_cipher()

2020-01-09T03:30:55Z

Currently, "cipher" (single-block cipher) spawns are usually initialized by using crypto_get_attr_alg() to look up the algorithm, then calling crypto_init_spawn(). In one case, crypto_grab_spawn() is used directly. The former way is different from how skcipher, aead, and akcipher spawns are initialized (they use crypto_grab_*()), and for no good reason. This difference introduces unnecessary complexity. The crypto_grab_*() functions used to have some problems, like not holding a reference to the algorithm and requiring the caller to initialize spawn->base.inst. But those problems are fixed now. Also, the cipher spawns are not strongly typed; e.g., the API requires that the user manually specify the flags CRYPTO_ALG_TYPE_CIPHER and CRYPTO_ALG_TYPE_MASK. Though the "cipher" algorithm type itself isn't yet strongly typed, we can start by making the spawns strongly typed. So, let's introduce a new 'struct crypto_cipher_spawn', and functions crypto_grab_cipher() and crypto_drop_cipher() to grab and drop them. Later patches will convert all cipher spawns to use these, then make crypto_spawn_cipher() take 'struct crypto_cipher_spawn' as well, instead of a bare 'struct crypto_spawn' as it currently does. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: algapi - pass instance to crypto_grab_spawn()

2020-01-09T03:30:54Z

Currently, crypto_spawn::inst is first used temporarily to pass the instance to crypto_grab_spawn(). Then crypto_init_spawn() overwrites it with crypto_spawn::next, which shares the same union. Finally, crypto_spawn::inst is set again when the instance is registered. Make this less convoluted by just passing the instance as an argument to crypto_grab_spawn() instead. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu