linux-kernel - [PATCH 5.6 163/254] crypto: rng - Fix a refcounting bug in crypto_rng

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Date:   Thu, 16 Apr 2020 15:24:12 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
        Neil Horman <nhorman@...driver.com>,
        Herbert Xu <herbert@...dor.apana.org.au>
Subject: [PATCH 5.6 163/254] crypto: rng - Fix a refcounting bug in crypto_rng_reset()

From: Dan Carpenter <dan.carpenter@...cle.com>

commit eed74b3eba9eda36d155c11a12b2b4b50c67c1d8 upstream.

We need to decrement this refcounter on these error paths.

Fixes: f7d76e05d058 ("crypto: user - fix use_after_free of struct xxx_request")
Cc: <stable@...r.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Acked-by: Neil Horman <nhorman@...driver.com>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 crypto/rng.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/crypto/rng.c
+++ b/crypto/rng.c
@@ -37,12 +37,16 @@ int crypto_rng_reset(struct crypto_rng *
 	crypto_stats_get(alg);
 	if (!seed && slen) {
 		buf = kmalloc(slen, GFP_KERNEL);
-		if (!buf)
+		if (!buf) {
+			crypto_alg_put(alg);
 			return -ENOMEM;
+		}
 
 		err = get_random_bytes_wait(buf, slen);
-		if (err)
+		if (err) {
+			crypto_alg_put(alg);
 			goto out;
+		}
 		seed = buf;
 	}