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authorDmitry Kasatkin <dmitry.kasatkin@intel.com>2011-12-05 13:17:42 +0200
committerDmitry Kasatkin <dmitry.kasatkin@intel.com>2011-12-20 17:50:08 +0200
commit97426f985729573cea06e82e271cc3929f1f5f8e (patch)
tree4aafe725018a95dc5c76ede5199d24aea524b060 /security
parentd21b59451886cb82448302f8d6f9ac87c3bd56cf (diff)
downloadlinux-linaro-97426f985729573cea06e82e271cc3929f1f5f8e.tar.gz
evm: prevent racing during tfm allocation
There is a small chance of racing during tfm allocation. This patch fixes it. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/evm/evm_crypto.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 4ad657d8809..8738deff26f 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -27,26 +27,35 @@ static int evmkey_len = MAX_KEY_SIZE;
struct crypto_shash *hmac_tfm;
+static DEFINE_MUTEX(mutex);
+
static struct shash_desc *init_desc(void)
{
int rc;
struct shash_desc *desc;
if (hmac_tfm == NULL) {
+ mutex_lock(&mutex);
+ if (hmac_tfm)
+ goto out;
hmac_tfm = crypto_alloc_shash(evm_hmac, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hmac_tfm)) {
pr_err("Can not allocate %s (reason: %ld)\n",
evm_hmac, PTR_ERR(hmac_tfm));
rc = PTR_ERR(hmac_tfm);
hmac_tfm = NULL;
+ mutex_unlock(&mutex);
return ERR_PTR(rc);
}
rc = crypto_shash_setkey(hmac_tfm, evmkey, evmkey_len);
if (rc) {
crypto_free_shash(hmac_tfm);
hmac_tfm = NULL;
+ mutex_unlock(&mutex);
return ERR_PTR(rc);
}
+out:
+ mutex_unlock(&mutex);
}
desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac_tfm),