From:   Eric Biggers <ebiggers@kernel.org>
To:     Herbert Xu <herbert@gondor.apana.org.au>,
        linux-crypto@vger.kernel.org
Cc:     keyrings@vger.kernel.org,
        Andrzej Zaborowski <andrew.zaborowski@intel.com>,
        stable@vger.kernel.org
Subject: [PATCH] crypto: rsa-pkcs1pad - only allow with rsa
Date:   Thu, 13 Jan 2022 11:34:35 -0800
Message-Id: <20220113193435.64281-1-ebiggers@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Eric Biggers <ebiggers@google.com>

The pkcs1pad template can be instantiated with an arbitrary akcipher
algorithm, which doesn't make sense; it is specifically an RSA padding
scheme.  Make it check that the underlying algorithm really is RSA.

Fixes: 3d5b1ecdea6f ("crypto: rsa - RSA padding algorithm")
Cc: <stable@vger.kernel.org> # v4.5+
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 crypto/rsa-pkcs1pad.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 8ac3e73e8ea6..1b3545781425 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -621,6 +621,11 @@ static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 
 	rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
 
+	if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) {
+		err = -EINVAL;
+		goto err_free_inst;
+	}
+
 	err = -ENAMETOOLONG;
 	hash_name = crypto_attr_alg_name(tb[2]);
 	if (IS_ERR(hash_name)) {

base-commit: feb7a43de5ef625ad74097d8fd3481d5dbc06a59
-- 
2.34.1