From 5f2d256875a5288b89b39b4f0d316ecb2306bf48 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 21 Mar 2021 22:07:48 -0700 Subject: [PATCH] crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS commit 30d0f6a956fc74bb2e948398daf3278c6b08c7e9 upstream. 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 Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/rng.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/crypto/rng.c b/crypto/rng.c index 1490d210f1a1..608d6ce1440a 100644 --- 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; - crypto_stats_get(alg); if (!seed && slen) { buf = kmalloc(slen, GFP_KERNEL); - if (!buf) { - crypto_alg_put(alg); + if (!buf) return -ENOMEM; - } err = get_random_bytes_wait(buf, slen); - if (err) { - crypto_alg_put(alg); + if (err) goto out; - } seed = buf; } + crypto_stats_get(alg); err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); crypto_stats_rng_seed(alg, err); out: