crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS

crypto_stats_get() is a no-op when the kernel is compiled without
CONFIG_CRYPTO_STATS, so pairing it with crypto_alg_put() unconditionally
(as crypto_rng_reset() does) is wrong.

Fix this by moving the call to crypto_stats_get() to just before the
actual algorithm operation which might need it.  This makes it always
paired with crypto_stats_rng_seed().

Fixes: eed74b3eba9e ("crypto: rng - Fix a refcounting bug in crypto_rng_reset()")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/rng.c b/crypto/rng.c
index a888d84..fea082b 100644 (file)
--- a/crypto/rng.c
+++ b/crypto/rng.c
@@ -34,22 +34,18 @@ int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
        u8 *buf = NULL;
        int err;
 
        u8 *buf = NULL;
        int err;
 

-       crypto_stats_get(alg);

        if (!seed && slen) {
                buf = kmalloc(slen, GFP_KERNEL);
        if (!seed && slen) {
                buf = kmalloc(slen, GFP_KERNEL);

-               if (!buf) {
-                       crypto_alg_put(alg);
+               if (!buf)

                        return -ENOMEM;
                        return -ENOMEM;

-               }

 
                err = get_random_bytes_wait(buf, slen);
 
                err = get_random_bytes_wait(buf, slen);

-               if (err) {
-                       crypto_alg_put(alg);
+               if (err)

                        goto out;
                        goto out;

-               }

                seed = buf;
        }
 
                seed = buf;
        }
 

+       crypto_stats_get(alg);

        err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
        crypto_stats_rng_seed(alg, err);
 out:
        err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
        crypto_stats_rng_seed(alg, err);
 out: