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| author | Dmitry Kasatkin <dmitry.kasatkin@intel.com> | 2011-12-05 13:17:42 +0200 |
|---|---|---|
| committer | Dmitry Kasatkin <dmitry.kasatkin@intel.com> | 2011-12-20 17:50:08 +0200 |
| commit | 97426f985729573cea06e82e271cc3929f1f5f8e (patch) | |
| tree | 4aafe725018a95dc5c76ede5199d24aea524b060 /security | |
| parent | d21b59451886cb82448302f8d6f9ac87c3bd56cf (diff) | |
| download | lwn-97426f985729573cea06e82e271cc3929f1f5f8e.tar.gz lwn-97426f985729573cea06e82e271cc3929f1f5f8e.zip | |
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.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index 4ad657d88097..8738deff26fa 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), |