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877b5691f2
The flags field in 'struct shash_desc' never actually does anything. The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP. However, no shash algorithm ever sleeps, making this flag a no-op. With this being the case, inevitably some users who can't sleep wrongly pass MAY_SLEEP. These would all need to be fixed if any shash algorithm actually started sleeping. For example, the shash_ahash_*() functions, which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP from the ahash API to the shash API. However, the shash functions are called under kmap_atomic(), so actually they're assumed to never sleep. Even if it turns out that some users do need preemption points while hashing large buffers, we could easily provide a helper function crypto_shash_update_large() which divides the data into smaller chunks and calls crypto_shash_update() and cond_resched() for each chunk. It's not necessary to have a flag in 'struct shash_desc', nor is it necessary to make individual shash algorithms aware of this at all. Therefore, remove shash_desc::flags, and document that the crypto_shash_*() functions can be called from any context. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
127 lines
2.5 KiB
C
127 lines
2.5 KiB
C
/*
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* AppArmor security module
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*
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* This file contains AppArmor policy loading interface function definitions.
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*
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* Copyright 2013 Canonical Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* Fns to provide a checksum of policy that has been loaded this can be
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* compared to userspace policy compiles to check loaded policy is what
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* it should be.
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*/
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#include <crypto/hash.h>
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#include "include/apparmor.h"
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#include "include/crypto.h"
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static unsigned int apparmor_hash_size;
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static struct crypto_shash *apparmor_tfm;
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unsigned int aa_hash_size(void)
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{
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return apparmor_hash_size;
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}
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char *aa_calc_hash(void *data, size_t len)
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{
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SHASH_DESC_ON_STACK(desc, apparmor_tfm);
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char *hash = NULL;
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int error = -ENOMEM;
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if (!apparmor_tfm)
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return NULL;
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hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
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if (!hash)
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goto fail;
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desc->tfm = apparmor_tfm;
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error = crypto_shash_init(desc);
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if (error)
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goto fail;
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error = crypto_shash_update(desc, (u8 *) data, len);
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if (error)
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goto fail;
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error = crypto_shash_final(desc, hash);
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if (error)
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goto fail;
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return hash;
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fail:
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kfree(hash);
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return ERR_PTR(error);
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}
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int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
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size_t len)
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{
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SHASH_DESC_ON_STACK(desc, apparmor_tfm);
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int error = -ENOMEM;
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__le32 le32_version = cpu_to_le32(version);
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if (!aa_g_hash_policy)
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return 0;
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if (!apparmor_tfm)
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return 0;
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profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
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if (!profile->hash)
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goto fail;
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desc->tfm = apparmor_tfm;
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error = crypto_shash_init(desc);
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if (error)
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goto fail;
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error = crypto_shash_update(desc, (u8 *) &le32_version, 4);
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if (error)
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goto fail;
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error = crypto_shash_update(desc, (u8 *) start, len);
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if (error)
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goto fail;
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error = crypto_shash_final(desc, profile->hash);
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if (error)
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goto fail;
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return 0;
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fail:
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kfree(profile->hash);
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profile->hash = NULL;
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return error;
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}
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static int __init init_profile_hash(void)
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{
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struct crypto_shash *tfm;
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if (!apparmor_initialized)
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return 0;
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tfm = crypto_alloc_shash("sha1", 0, 0);
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if (IS_ERR(tfm)) {
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int error = PTR_ERR(tfm);
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AA_ERROR("failed to setup profile sha1 hashing: %d\n", error);
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return error;
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}
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apparmor_tfm = tfm;
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apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm);
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aa_info_message("AppArmor sha1 policy hashing enabled");
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return 0;
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}
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late_initcall(init_profile_hash);
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