crypto: aesni-intel - Don't leak memory in rfc4106_set_hash_subkey

There's a small memory leak in
arch/x86/crypto/aesni-intel_glue.c::rfc4106_set_hash_subkey(). If the call
to kmalloc() fails and returns NULL then the memory allocated previously
by ablkcipher_request_alloc() is not freed when we leave the function.

I could have just added a call to ablkcipher_request_free() before we
return -ENOMEM, but that started to look too much like the code we
already had at the end of the function, so I chose instead to rework the
code a bit so that there are now a few labels at the end that we goto when
various allocations fail, so we don't have to repeat the same blocks of
code (this also reduces the object code size slightly).

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index e1e60c7..e013552 100644 (file)
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -873,21 +873,19 @@ rfc4106_set_hash_subkey(u8 *hash_subkey, const u8 *key, unsigned int key_len)
        crypto_ablkcipher_clear_flags(ctr_tfm, ~0);
 
        ret = crypto_ablkcipher_setkey(ctr_tfm, key, key_len);
-       if (ret) {
-               crypto_free_ablkcipher(ctr_tfm);
-               return ret;
-       }
+       if (ret)
+               goto out;
 
        req = ablkcipher_request_alloc(ctr_tfm, GFP_KERNEL);
        if (!req) {
-               crypto_free_ablkcipher(ctr_tfm);
-               return -EINVAL;
+               ret = -EINVAL;
+               goto out_free_ablkcipher;
        }
 
        req_data = kmalloc(sizeof(*req_data), GFP_KERNEL);
        if (!req_data) {
-               crypto_free_ablkcipher(ctr_tfm);
-               return -ENOMEM;
+               ret = -ENOMEM;
+               goto out_free_request;
        }
        memset(req_data->iv, 0, sizeof(req_data->iv));
 
@@ -913,9 +911,12 @@ rfc4106_set_hash_subkey(u8 *hash_subkey, const u8 *key, unsigned int key_len)
                if (!ret)
                        ret = req_data->result.err;
        }
+out_free_request:
        ablkcipher_request_free(req);
        kfree(req_data);
+out_free_ablkcipher:
        crypto_free_ablkcipher(ctr_tfm);
+out:
        return ret;
 }