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linux-next/security/apparmor/crypto.c
Nicolas Iooss 9814448da7 apparmor: use SHASH_DESC_ON_STACK
When building the kernel with clang, the compiler fails to build
security/apparmor/crypto.c with the following error:

    security/apparmor/crypto.c:36:8: error: fields must have a constant
    size: 'variable length array in structure' extension will never be
    supported
                    char ctx[crypto_shash_descsize(apparmor_tfm)];
                         ^

Since commit a0a77af141 ("crypto: LLVMLinux: Add macro to remove use
of VLAIS in crypto code"), include/crypto/hash.h defines
SHASH_DESC_ON_STACK to work around this issue. Use it in aa_calc_hash()
and aa_calc_profile_hash().

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-04-07 08:58:35 +10:00

130 lines
2.5 KiB
C

/*
* AppArmor security module
*
* This file contains AppArmor policy loading interface function definitions.
*
* Copyright 2013 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
* Fns to provide a checksum of policy that has been loaded this can be
* compared to userspace policy compiles to check loaded policy is what
* it should be.
*/
#include <crypto/hash.h>
#include "include/apparmor.h"
#include "include/crypto.h"
static unsigned int apparmor_hash_size;
static struct crypto_shash *apparmor_tfm;
unsigned int aa_hash_size(void)
{
return apparmor_hash_size;
}
char *aa_calc_hash(void *data, size_t len)
{
SHASH_DESC_ON_STACK(desc, apparmor_tfm);
char *hash = NULL;
int error = -ENOMEM;
if (!apparmor_tfm)
return NULL;
hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
if (!hash)
goto fail;
desc->tfm = apparmor_tfm;
desc->flags = 0;
error = crypto_shash_init(desc);
if (error)
goto fail;
error = crypto_shash_update(desc, (u8 *) data, len);
if (error)
goto fail;
error = crypto_shash_final(desc, hash);
if (error)
goto fail;
return hash;
fail:
kfree(hash);
return ERR_PTR(error);
}
int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
size_t len)
{
SHASH_DESC_ON_STACK(desc, apparmor_tfm);
int error = -ENOMEM;
__le32 le32_version = cpu_to_le32(version);
if (!aa_g_hash_policy)
return 0;
if (!apparmor_tfm)
return 0;
profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
if (!profile->hash)
goto fail;
desc->tfm = apparmor_tfm;
desc->flags = 0;
error = crypto_shash_init(desc);
if (error)
goto fail;
error = crypto_shash_update(desc, (u8 *) &le32_version, 4);
if (error)
goto fail;
error = crypto_shash_update(desc, (u8 *) start, len);
if (error)
goto fail;
error = crypto_shash_final(desc, profile->hash);
if (error)
goto fail;
return 0;
fail:
kfree(profile->hash);
profile->hash = NULL;
return error;
}
static int __init init_profile_hash(void)
{
struct crypto_shash *tfm;
if (!apparmor_initialized)
return 0;
tfm = crypto_alloc_shash("sha1", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm)) {
int error = PTR_ERR(tfm);
AA_ERROR("failed to setup profile sha1 hashing: %d\n", error);
return error;
}
apparmor_tfm = tfm;
apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm);
aa_info_message("AppArmor sha1 policy hashing enabled");
return 0;
}
late_initcall(init_profile_hash);