linux-kernel - [PATCH] crypto: ecc: fix NULL pointer dereferencing in ecc_gen

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Message-ID: <20240307071318.5206-1-r.smirnov@omp.ru>
Date: Thu, 7 Mar 2024 10:13:18 +0300
From: Roman Smirnov <r.smirnov@....ru>
To: Herbert Xu <herbert@...dor.apana.org.au>, "David S. Miller"
	<davem@...emloft.net>
CC: Roman Smirnov <r.smirnov@....ru>, Sergey Shtylyov <s.shtylyov@....ru>,
	Karina Yankevich <k.yankevich@....ru>, <linux-crypto@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <lvc-project@...uxtesting.org>
Subject: [PATCH] crypto: ecc: fix NULL pointer dereferencing in ecc_gen_privkey()

ecc_get_curve() can return NULL. It is necessary to check
for NULL before dereferencing.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Roman Smirnov <r.smirnov@....ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@....ru>
---
 crypto/ecc.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/crypto/ecc.c b/crypto/ecc.c
index f53fb4d6af99..fd63e354895b 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -1471,9 +1471,14 @@ int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
 	const struct ecc_curve *curve = ecc_get_curve(curve_id);
 	u64 priv[ECC_MAX_DIGITS];
 	unsigned int nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
-	unsigned int nbits = vli_num_bits(curve->n, ndigits);
+	unsigned int nbits;
 	int err;
 
+	if (!curve)
+		return -EINVAL;
+
+	nbits = vli_num_bits(curve->n, ndigits);
+
 	/* Check that N is included in Table 1 of FIPS 186-4, section 6.1.1 */
 	if (nbits < 160 || ndigits > ARRAY_SIZE(priv))
 		return -EINVAL;
-- 
2.34.1