It might be possible for two callers to race the mutex lock after the
NULL ctx check. Instead, move the lock above the check so there isn't
the possibility of leaking a crypto ctx. Additionally, report the full
algo name when failing.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/ecryptfs/crypto.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index d107576..c134346 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -618,27 +618,28 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
"key_size_bits = [%zd]\n",
crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
crypt_stat->key_size << 3);
+ mutex_lock(&crypt_stat->cs_tfm_mutex);
if (crypt_stat->tfm) {
rc = 0;
- goto out;
+ goto out_unlock;
}
- mutex_lock(&crypt_stat->cs_tfm_mutex);
rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
crypt_stat->cipher, "cbc");
if (rc)
goto out_unlock;
crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
- kfree(full_alg_name);
if (IS_ERR(crypt_stat->tfm)) {
rc = PTR_ERR(crypt_stat->tfm);
crypt_stat->tfm = NULL;
ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
"Error initializing cipher [%s]\n",
- crypt_stat->cipher);
- goto out_unlock;
+ full_alg_name);
+ goto out_free;
}
crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
rc = 0;
+out_free:
+ kfree(full_alg_name);
out_unlock:
mutex_unlock(&crypt_stat->cs_tfm_mutex);
out:
--
1.7.9.5
--
Kees Cook
Chrome OS Security
--
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