1 files changed, 276 insertions, 0 deletions
diff --git a/crypto/hmac.c b/crypto/hmac.c
new file mode 100644
index 000000000..e74730224
--- /dev/null
+++ b/crypto/hmac.c
@@ -0,0 +1,276 @@
+/*
+ * Cryptographic API.
+ *
+ * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * The HMAC implementation is derived from USAGI.
+ * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <crypto/hmac.h>
+#include <crypto/internal/hash.h>
+#include <crypto/scatterwalk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/string.h>
+
+struct hmac_ctx {
+	struct crypto_shash *hash;
+};
+
+static inline void *align_ptr(void *p, unsigned int align)
+{
+	return (void *)ALIGN((unsigned long)p, align);
+}
+
+static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
+{
+	return align_ptr(crypto_shash_ctx_aligned(tfm) +
+			 crypto_shash_statesize(tfm) * 2,
+			 crypto_tfm_ctx_alignment());
+}
+
+static int hmac_setkey(struct crypto_shash *parent,
+		       const u8 *inkey, unsigned int keylen)
+{
+	int bs = crypto_shash_blocksize(parent);
+	int ds = crypto_shash_digestsize(parent);
+	int ss = crypto_shash_statesize(parent);
+	char *ipad = crypto_shash_ctx_aligned(parent);
+	char *opad = ipad + ss;
+	struct hmac_ctx *ctx = align_ptr(opad + ss,
+					 crypto_tfm_ctx_alignment());
+	struct crypto_shash *hash = ctx->hash;
+	SHASH_DESC_ON_STACK(shash, hash);
+	unsigned int i;
+
+	shash->tfm = hash;
+	shash->flags = crypto_shash_get_flags(parent)
+		& CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	if (keylen > bs) {
+		int err;
+
+		err = crypto_shash_digest(shash, inkey, keylen, ipad);
+		if (err)
+			return err;
+
+		keylen = ds;
+	} else
+		memcpy(ipad, inkey, keylen);
+
+	memset(ipad + keylen, 0, bs - keylen);
+	memcpy(opad, ipad, bs);
+
+	for (i = 0; i < bs; i++) {
+		ipad[i] ^= HMAC_IPAD_VALUE;
+		opad[i] ^= HMAC_OPAD_VALUE;
+	}
+
+	return crypto_shash_init(shash) ?:
+	       crypto_shash_update(shash, ipad, bs) ?:
+	       crypto_shash_export(shash, ipad) ?:
+	       crypto_shash_init(shash) ?:
+	       crypto_shash_update(shash, opad, bs) ?:
+	       crypto_shash_export(shash, opad);
+}
+
+static int hmac_export(struct shash_desc *pdesc, void *out)
+{
+	struct shash_desc *desc = shash_desc_ctx(pdesc);
+
+	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	return crypto_shash_export(desc, out);
+}
+
+static int hmac_import(struct shash_desc *pdesc, const void *in)
+{
+	struct shash_desc *desc = shash_desc_ctx(pdesc);
+	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
+
+	desc->tfm = ctx->hash;
+	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	return crypto_shash_import(desc, in);
+}
+
+static int hmac_init(struct shash_desc *pdesc)
+{
+	return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
+}
+
+static int hmac_update(struct shash_desc *pdesc,
+		       const u8 *data, unsigned int nbytes)
+{
+	struct shash_desc *desc = shash_desc_ctx(pdesc);
+
+	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	return crypto_shash_update(desc, data, nbytes);
+}
+
+static int hmac_final(struct shash_desc *pdesc, u8 *out)
+{
+	struct crypto_shash *parent = pdesc->tfm;
+	int ds = crypto_shash_digestsize(parent);
+	int ss = crypto_shash_statesize(parent);
+	char *opad = crypto_shash_ctx_aligned(parent) + ss;
+	struct shash_desc *desc = shash_desc_ctx(pdesc);
+
+	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	return crypto_shash_final(desc, out) ?:
+	       crypto_shash_import(desc, opad) ?:
+	       crypto_shash_finup(desc, out, ds, out);
+}
+
+static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
+		      unsigned int nbytes, u8 *out)
+{
+
+	struct crypto_shash *parent = pdesc->tfm;
+	int ds = crypto_shash_digestsize(parent);
+	int ss = crypto_shash_statesize(parent);
+	char *opad = crypto_shash_ctx_aligned(parent) + ss;
+	struct shash_desc *desc = shash_desc_ctx(pdesc);
+
+	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	return crypto_shash_finup(desc, data, nbytes, out) ?:
+	       crypto_shash_import(desc, opad) ?:
+	       crypto_shash_finup(desc, out, ds, out);
+}
+
+static int hmac_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_shash *parent = __crypto_shash_cast(tfm);
+	struct crypto_shash *hash;
+	struct crypto_instance *inst = (void *)tfm->__crt_alg;
+	struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
+	struct hmac_ctx *ctx = hmac_ctx(parent);
+
+	hash = crypto_spawn_shash(spawn);
+	if (IS_ERR(hash))
+		return PTR_ERR(hash);
+
+	parent->descsize = sizeof(struct shash_desc) +
+			   crypto_shash_descsize(hash);
+
+	ctx->hash = hash;
+	return 0;
+}
+
+static void hmac_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
+	crypto_free_shash(ctx->hash);
+}
+
+static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct shash_instance *inst;
+	struct crypto_alg *alg;
+	struct shash_alg *salg;
+	int err;
+	int ds;
+	int ss;
+
+	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
+	if (err)
+		return err;
+
+	salg = shash_attr_alg(tb[1], 0, 0);
+	if (IS_ERR(salg))
+		return PTR_ERR(salg);
+	alg = &salg->base;
+
+	/* The underlying hash algorithm must be unkeyed */
+	err = -EINVAL;
+	if (crypto_shash_alg_has_setkey(salg))
+		goto out_put_alg;
+
+	ds = salg->digestsize;
+	ss = salg->statesize;
+	if (ds > alg->cra_blocksize ||
+	    ss < alg->cra_blocksize)
+		goto out_put_alg;
+
+	inst = shash_alloc_instance("hmac", alg);
+	err = PTR_ERR(inst);
+	if (IS_ERR(inst))
+		goto out_put_alg;
+
+	err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
+				      shash_crypto_instance(inst));
+	if (err)
+		goto out_free_inst;
+
+	inst->alg.base.cra_priority = alg->cra_priority;
+	inst->alg.base.cra_blocksize = alg->cra_blocksize;
+	inst->alg.base.cra_alignmask = alg->cra_alignmask;
+
+	ss = ALIGN(ss, alg->cra_alignmask + 1);
+	inst->alg.digestsize = ds;
+	inst->alg.statesize = ss;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
+				     ALIGN(ss * 2, crypto_tfm_ctx_alignment());
+
+	inst->alg.base.cra_init = hmac_init_tfm;
+	inst->alg.base.cra_exit = hmac_exit_tfm;
+
+	inst->alg.init = hmac_init;
+	inst->alg.update = hmac_update;
+	inst->alg.final = hmac_final;
+	inst->alg.finup = hmac_finup;
+	inst->alg.export = hmac_export;
+	inst->alg.import = hmac_import;
+	inst->alg.setkey = hmac_setkey;
+
+	err = shash_register_instance(tmpl, inst);
+	if (err) {
+out_free_inst:
+		shash_free_instance(shash_crypto_instance(inst));
+	}
+
+out_put_alg:
+	crypto_mod_put(alg);
+	return err;
+}
+
+static struct crypto_template hmac_tmpl = {
+	.name = "hmac",
+	.create = hmac_create,
+	.free = shash_free_instance,
+	.module = THIS_MODULE,
+};
+
+static int __init hmac_module_init(void)
+{
+	return crypto_register_template(&hmac_tmpl);
+}
+
+static void __exit hmac_module_exit(void)
+{
+	crypto_unregister_template(&hmac_tmpl);
+}
+
+module_init(hmac_module_init);
+module_exit(hmac_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("HMAC hash algorithm");
+MODULE_ALIAS_CRYPTO("hmac");