crypto: sig - Add interface for sign/verify

Split out the sign/verify functionality from the existing akcipher
interface.  Most algorithms in akcipher either support encryption
and decryption, or signing and verify.  Only one supports both.

As a signature algorithm may not support encryption at all, these
two should be spearated.

For now sig is simply a wrapper around akcipher as all algorithms
remain unchanged.  This is a first step and allows users to start
allocating sig instead of akcipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 159 insertions, 0 deletions

diff --git a/crypto/sig.c b/crypto/sig.c
new file mode 100644
index 000000000000..d812555c88af
--- /dev/null
+++ b/crypto/sig.c
@@ -0,0 +1,159 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Public Key Signature Algorithm
+ *
+ * Copyright (c) 2023 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <crypto/akcipher.h>
+#include <crypto/internal/sig.h>
+#include <linux/cryptouser.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <net/netlink.h>
+
+#include "internal.h"
+
+#define CRYPTO_ALG_TYPE_SIG_MASK	0x0000000e
+
+static const struct crypto_type crypto_sig_type;
+
+static inline struct crypto_sig *__crypto_sig_tfm(struct crypto_tfm *tfm)
+{
+	return container_of(tfm, struct crypto_sig, base);
+}
+
+static int crypto_sig_init_tfm(struct crypto_tfm *tfm)
+{
+	if (tfm->__crt_alg->cra_type != &crypto_sig_type)
+		return crypto_init_akcipher_ops_sig(tfm);
+
+	return 0;
+}
+
+static void __maybe_unused crypto_sig_show(struct seq_file *m,
+					   struct crypto_alg *alg)
+{
+	seq_puts(m, "type         : sig\n");
+}
+
+static int __maybe_unused crypto_sig_report(struct sk_buff *skb,
+					    struct crypto_alg *alg)
+{
+	struct crypto_report_akcipher rsig = {};
+
+	strscpy(rsig.type, "sig", sizeof(rsig.type));
+
+	return nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER, sizeof(rsig), &rsig);
+}
+
+static int __maybe_unused crypto_sig_report_stat(struct sk_buff *skb,
+						 struct crypto_alg *alg)
+{
+	struct crypto_stat_akcipher rsig = {};
+
+	strscpy(rsig.type, "sig", sizeof(rsig.type));
+
+	return nla_put(skb, CRYPTOCFGA_STAT_AKCIPHER, sizeof(rsig), &rsig);
+}
+
+static const struct crypto_type crypto_sig_type = {
+	.extsize = crypto_alg_extsize,
+	.init_tfm = crypto_sig_init_tfm,
+#ifdef CONFIG_PROC_FS
+	.show = crypto_sig_show,
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_USER)
+	.report = crypto_sig_report,
+#endif
+#ifdef CONFIG_CRYPTO_STATS
+	.report_stat = crypto_sig_report_stat,
+#endif
+	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
+	.maskset = CRYPTO_ALG_TYPE_SIG_MASK,
+	.type = CRYPTO_ALG_TYPE_SIG,
+	.tfmsize = offsetof(struct crypto_sig, base),
+};
+
+struct crypto_sig *crypto_alloc_sig(const char *alg_name, u32 type, u32 mask)
+{
+	return crypto_alloc_tfm(alg_name, &crypto_sig_type, type, mask);
+}
+EXPORT_SYMBOL_GPL(crypto_alloc_sig);
+
+int crypto_sig_maxsize(struct crypto_sig *tfm)
+{
+	struct crypto_akcipher **ctx = crypto_sig_ctx(tfm);
+
+	return crypto_akcipher_maxsize(*ctx);
+}
+EXPORT_SYMBOL_GPL(crypto_sig_maxsize);
+
+int crypto_sig_sign(struct crypto_sig *tfm,
+		    const void *src, unsigned int slen,
+		    void *dst, unsigned int dlen)
+{
+	struct crypto_akcipher **ctx = crypto_sig_ctx(tfm);
+	struct crypto_akcipher_sync_data data = {
+		.tfm = *ctx,
+		.src = src,
+		.dst = dst,
+		.slen = slen,
+		.dlen = dlen,
+	};
+
+	return crypto_akcipher_sync_prep(&data) ?:
+	       crypto_akcipher_sync_post(&data,
+					 crypto_akcipher_sign(data.req));
+}
+EXPORT_SYMBOL_GPL(crypto_sig_sign);
+
+int crypto_sig_verify(struct crypto_sig *tfm,
+		      const void *src, unsigned int slen,
+		      const void *digest, unsigned int dlen)
+{
+	struct crypto_akcipher **ctx = crypto_sig_ctx(tfm);
+	struct crypto_akcipher_sync_data data = {
+		.tfm = *ctx,
+		.src = src,
+		.slen = slen,
+		.dlen = dlen,
+	};
+	int err;
+
+	err = crypto_akcipher_sync_prep(&data);
+	if (err)
+		return err;
+
+	sg_init_table(data.sg, 2);
+	sg_set_buf(&data.sg[0], src, slen);
+	sg_set_buf(&data.sg[1], digest, dlen);
+
+	return crypto_akcipher_sync_post(&data,
+					 crypto_akcipher_verify(data.req));
+}
+EXPORT_SYMBOL_GPL(crypto_sig_verify);
+
+int crypto_sig_set_pubkey(struct crypto_sig *tfm,
+			  const void *key, unsigned int keylen)
+{
+	struct crypto_akcipher **ctx = crypto_sig_ctx(tfm);
+
+	return crypto_akcipher_set_pub_key(*ctx, key, keylen);
+}
+EXPORT_SYMBOL_GPL(crypto_sig_set_pubkey);
+
+int crypto_sig_set_privkey(struct crypto_sig *tfm,
+			  const void *key, unsigned int keylen)
+{
+	struct crypto_akcipher **ctx = crypto_sig_ctx(tfm);
+
+	return crypto_akcipher_set_priv_key(*ctx, key, keylen);
+}
+EXPORT_SYMBOL_GPL(crypto_sig_set_privkey);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Public Key Signature Algorithms");