From: Ignat Korchagin ignat@cloudflare.com
[ Upstream commit bc155c6c188c2f0c5749993b1405673d25a80389 ]
Changes from v1: * removed the default implementation from set_pub_key: it is assumed that an implementation must always have this callback defined as there are no use case for an algorithm, which doesn't need a public key
Many akcipher implementations (like ECDSA) support only signature verifications, so they don't have all callbacks defined.
Commit 78a0324f4a53 ("crypto: akcipher - default implementations for request callbacks") introduced default callbacks for sign/verify operations, which just return an error code.
However, these are not enough, because before calling sign the caller would likely call set_priv_key first on the instantiated transform (as the in-kernel testmgr does). This function does not have a default stub, so the kernel crashes, when trying to set a private key on an akcipher, which doesn't support signature generation.
I've noticed this, when trying to add a KAT vector for ECDSA signature to the testmgr.
With this patch the testmgr returns an error in dmesg (as it should) instead of crashing the kernel NULL ptr dereference.
Fixes: 78a0324f4a53 ("crypto: akcipher - default implementations for request callbacks") Signed-off-by: Ignat Korchagin ignat@cloudflare.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin sashal@kernel.org --- crypto/akcipher.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/crypto/akcipher.c b/crypto/akcipher.c index f866085c8a4a..ab975a420e1e 100644 --- a/crypto/akcipher.c +++ b/crypto/akcipher.c @@ -120,6 +120,12 @@ static int akcipher_default_op(struct akcipher_request *req) return -ENOSYS; }
+static int akcipher_default_set_key(struct crypto_akcipher *tfm, + const void *key, unsigned int keylen) +{ + return -ENOSYS; +} + int crypto_register_akcipher(struct akcipher_alg *alg) { struct crypto_alg *base = &alg->base; @@ -132,6 +138,8 @@ int crypto_register_akcipher(struct akcipher_alg *alg) alg->encrypt = akcipher_default_op; if (!alg->decrypt) alg->decrypt = akcipher_default_op; + if (!alg->set_priv_key) + alg->set_priv_key = akcipher_default_set_key;
akcipher_prepare_alg(alg); return crypto_register_alg(base);