evm: Fix memleak in init_desc

tmp_tfm is allocated, but not freed on subsequent kmalloc failure, which
leads to a memory leak.  Free tmp_tfm.

Fixes: d46eb3699502b ("evm: crypto hash replaced by shash")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
[zohar@linux.ibm.com: formatted/reworded patch description]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 168c3b78ac47b752c0543ccb3a0a626d8d021cc0..a6dd47eb086da079e5974e491cf554e3eeb11fd0 100644 (file)
--- 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 @@ unlock:
 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);
        }