Patch "evm: Fix memleak in init_desc" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    evm: Fix memleak in init_desc

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     evm-fix-memleak-in-init_desc.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 97c654ef762ccc252ef6c7260cb8c8fab7aaa23c
Author: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
Date:   Sun Jan 10 16:02:53 2021 +0800

    evm: Fix memleak in init_desc
    
    [ Upstream commit ccf11dbaa07b328fa469415c362d33459c140a37 ]
    
    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@xxxxxxxxxx>
    [zohar@xxxxxxxxxxxxx: formatted/reworded patch description]
    Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index ee6bd945f3d6a..25dac691491b1 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -75,7 +75,7 @@ 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) {
@@ -120,13 +120,16 @@ 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);
 	}