kernel/crypto/skcipher.c, branch linux-5.10.y

mm, treewide: rename kzfree() to kfree_sensitive()

2020-08-07T18:33:22Z

As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches Signed-off-by: Waiman Long Signed-off-by: Andrew Morton Acked-by: David Howells Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Jarkko Sakkinen Cc: James Morris Cc: "Serge E. Hallyn" Cc: Joe Perches Cc: Matthew Wilcox Cc: David Rientjes Cc: Dan Carpenter Cc: "Jason A . Donenfeld" Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds

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 - enforce that all instances have a ->free() method

2020-01-09T03:30:58Z

All instances need to have a ->free() method, but people could forget to set it and then not notice if the instance is never unregistered. To help detect this bug earlier, don't allow an instance without a ->free() method to be registered, and complain loudly if someone tries to do it. 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: skcipher - use crypto_grab_cipher() and simplify error paths

2020-01-09T03:30:56Z

Make skcipher_alloc_instance_simple() use the new function crypto_grab_cipher() to initialize its cipher spawn. This is needed to make all spawns be initialized in a consistent way. Also simplify the error handling by taking advantage of crypto_drop_*() now accepting (as a no-op) spawns that haven't been initialized yet, and by taking advantage of crypto_grab_*() now handling ERR_PTR() names. 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

crypto: skcipher - pass instance to crypto_grab_skcipher()

2020-01-09T03:30:54Z

Initializing a crypto_skcipher_spawn currently requires: 1. Set spawn->base.inst to point to the instance. 2. Call crypto_grab_skcipher(). But there's no reason for these steps to be separate, and in fact this unneeded complication has caused at least one bug, the one fixed by commit 6db43410179b ("crypto: adiantum - initialize crypto_spawn::inst") So just make crypto_grab_skcipher() take the instance as an argument. To keep the function calls from getting too unwieldy due to this extra argument, also introduce a 'mask' variable into the affected places which weren't already using one. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: remove propagation of CRYPTO_TFM_RES_* flags

2020-01-09T03:30:53Z

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 Signed-off-by: Herbert Xu

crypto: remove CRYPTO_TFM_RES_BAD_KEY_LEN

2020-01-09T03:30:53Z

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 Reviewed-by: Horia Geantă Signed-off-by: Herbert Xu