[PATCH] [v2] evm: Fix memleak in init_desc

[Dinghao Liu]

When kmalloc() fails, tmp_tfm allocated by
crypto_alloc_shash() has not been freed, which
leads to memleak.

Fixes: d46eb3699502b ("evm: crypto hash replaced by shash")
Signed-off-by: Dinghao Liu <dinghao....@zju.edu.cn>
---

Changelog:

v2: - Remove checks against tmp_tfm before freeing.
---
 security/integrity/evm/evm_crypto.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/security/integrity/evm/evm_crypto.c 
b/security/integrity/evm/evm_crypto.c
index 168c3b78ac47..a6dd47eb086d 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -73,7 +73,7 @@ static struct shash_desc *init_desc(char type, uint8_t 
hash_algo)
 {
        long rc;
        const char *algo;
-       struct crypto_shash **tfm, *tmp_tfm;
+       struct crypto_shash **tfm, *tmp_tfm = NULL;
        struct shash_desc *desc;
 
        if (type == EVM_XATTR_HMAC) {
@@ -118,13 +118,16 @@ static struct shash_desc *init_desc(char type, uint8_t 
hash_algo)
 alloc:
        desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm),
                        GFP_KERNEL);
-       if (!desc)
+       if (!desc) {
+               crypto_free_shash(tmp_tfm);
                return ERR_PTR(-ENOMEM);
+       }
 
        desc->tfm = *tfm;
 
        rc = crypto_shash_init(desc);
        if (rc) {
+               crypto_free_shash(tmp_tfm);
                kfree(desc);
                return ERR_PTR(rc);
        }
-- 
2.17.1