kernel/linux.git/crypto/shash.c, branch v6.3.2

crypto: scatterwalk - use kmap_local() not kmap_atomic()

2022-12-30T14:56:27+00:00

kmap_atomic() is used to create short-lived mappings of pages that may not be accessible via the kernel direct map. This is only needed on 32-bit architectures that implement CONFIG_HIGHMEM, but it can be used on 64-bit other architectures too, where the returned mapping is simply the kernel direct address of the page. However, kmap_atomic() does not support migration on CONFIG_HIGHMEM configurations, due to the use of per-CPU kmap slots, and so it disables preemption on all architectures, not just the 32-bit ones. This implies that all scatterwalk based crypto routines essentially execute with preemption disabled all the time, which is less than ideal. So let's switch scatterwalk_map/_unmap and the shash/ahash routines to kmap_local() instead, which serves a similar purpose, but without the resulting impact on preemption on architectures that have no need for CONFIG_HIGHMEM. Cc: Eric Biggers Cc: Herbert Xu Cc: "Elliott, Robert (Servers)" Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu

crypto: api - Increase MAX_ALGAPI_ALIGNMASK to 127

2022-12-02T10:12:40+00:00

Previously we limited the maximum alignment mask to 63. This is mostly due to stack usage for shash. This patch introduces a separate limit for shash algorithms and increases the general limit to 127 which is the value that we need for DMA allocations on arm64. Signed-off-by: Herbert Xu

Revert "crypto: shash - avoid comparing pointers to exported functions under CFI"

2022-11-25T09:39:19+00:00

This reverts commit 22ca9f4aaf431a9413dcc115dd590123307f274f because CFI no longer breaks cross-module function address equality, so crypto_shash_alg_has_setkey() can now be an inline function like before. This commit should not be backported to kernels that don't have the new CFI implementation. Acked-by: Peter Zijlstra (Intel) Reviewed-by: Sami Tolvanen Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: add crypto_has_shash()

2022-08-02T23:14:47+00:00

Add helper function to determine if a given synchronous hash is supported. Signed-off-by: Hannes Reinecke Reviewed-by: Sagi Grimberg Reviewed-by: Chaitanya Kulkarni Reviewed-by: Himanshu Madhani Acked-by: Herbert Xu Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

crypto: shash - avoid comparing pointers to exported functions under CFI

2021-06-17T07:07:31+00:00

crypto_shash_alg_has_setkey() is implemented by testing whether the .setkey() member of a struct shash_alg points to the default version, called shash_no_setkey(). As crypto_shash_alg_has_setkey() is a static inline, this requires shash_no_setkey() to be exported to modules. Unfortunately, when building with CFI, function pointers are routed via CFI stubs which are private to each module (or to the kernel proper) and so this function pointer comparison may fail spuriously. Let's fix this by turning crypto_shash_alg_has_setkey() into an out of line function. Cc: Sami Tolvanen Cc: Eric Biggers Signed-off-by: Ard Biesheuvel Reviewed-by: Eric Biggers Reviewed-by: Sami Tolvanen Signed-off-by: Herbert Xu

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

2020-08-07T18:33:22+00:00

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: hash - introduce crypto_shash_tfm_digest()

2020-05-08T05:32:12+00:00

Currently the simplest use of the shash API is to use crypto_shash_digest() to digest a whole buffer. However, this still requires allocating a hash descriptor (struct shash_desc). Many users don't really want to preallocate one and instead just use a one-off descriptor on the stack like the following: { SHASH_DESC_ON_STACK(desc, tfm); int err; desc->tfm = tfm; err = crypto_shash_digest(desc, data, len, out); shash_desc_zero(desc); } Wrap this in a new helper function crypto_shash_tfm_digest() that can be used instead of the above. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

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

2020-01-09T03:30:58+00:00

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

2020-01-09T03:30:58+00:00

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: shash - convert shash_free_instance() to new style

2020-01-09T03:30:57+00:00

Convert shash_free_instance() and its users to the new way of freeing instances, where a ->free() method is installed to the instance struct itself. This replaces the weakly-typed method crypto_template::free(). This will allow removing support for the old way of freeing instances. Also give shash_free_instance() a more descriptive name to reflect that it's only for instances with a single spawn, not for any instance. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu