crypto: hash - Add shash interface

The shash interface replaces the current synchronous hash interface.
It improves over hash in two ways.  Firstly shash is reentrant,
meaning that the same tfm may be used by two threads simultaneously
as all hashing state is stored in a local descriptor.

The other enhancement is that shash no longer takes scatter list
entries.  This is because shash is specifically designed for
synchronous algorithms and as such scatter lists are unnecessary.

All existing hash users will be converted to shash once the
algorithms have been completely converted.

There is also a new finup function that combines update with final.
This will be extended to ahash once the algorithm conversion is
done.

This is also the first time that an algorithm type has their own
registration function.  Existing algorithm types will be converted
to this way in due course.

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

1 files changed, 239 insertions, 0 deletions

diff --git a/crypto/shash.c b/crypto/shash.c
new file mode 100644
index 0000000..82ec4bd
--- /dev/null
+++ b/crypto/shash.c
@@ -0,0 +1,239 @@
+/*
+ * Synchronous Cryptographic Hash operations.
+ *
+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * 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/internal/hash.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+
+static inline struct crypto_shash *__crypto_shash_cast(struct crypto_tfm *tfm)
+{
+	return container_of(tfm, struct crypto_shash, base);
+}
+
+static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
+				  unsigned int keylen)
+{
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+	unsigned long absize;
+	u8 *buffer, *alignbuffer;
+	int err;
+
+	absize = keylen + (alignmask & ~(CRYPTO_MINALIGN - 1));
+	buffer = kmalloc(absize, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
+	memcpy(alignbuffer, key, keylen);
+	err = shash->setkey(tfm, alignbuffer, keylen);
+	memset(alignbuffer, 0, keylen);
+	kfree(buffer);
+	return err;
+}
+
+int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
+			unsigned int keylen)
+{
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+
+	if ((unsigned long)key & alignmask)
+		return shash_setkey_unaligned(tfm, key, keylen);
+
+	return shash->setkey(tfm, key, keylen);
+}
+EXPORT_SYMBOL_GPL(crypto_shash_setkey);
+
+static inline unsigned int shash_align_buffer_size(unsigned len,
+						   unsigned long mask)
+{
+	return len + (mask & ~(__alignof__(u8 __attribute__ ((aligned))) - 1));
+}
+
+static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
+				  unsigned int len)
+{
+	struct crypto_shash *tfm = desc->tfm;
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+	unsigned int unaligned_len = alignmask + 1 -
+				     ((unsigned long)data & alignmask);
+	u8 buf[shash_align_buffer_size(unaligned_len, alignmask)]
+		__attribute__ ((aligned));
+
+	memcpy(buf, data, unaligned_len);
+
+	return shash->update(desc, buf, unaligned_len) ?:
+	       shash->update(desc, data + unaligned_len, len - unaligned_len);
+}
+
+int crypto_shash_update(struct shash_desc *desc, const u8 *data,
+			unsigned int len)
+{
+	struct crypto_shash *tfm = desc->tfm;
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+
+	if ((unsigned long)data & alignmask)
+		return shash_update_unaligned(desc, data, len);
+
+	return shash->update(desc, data, len);
+}
+EXPORT_SYMBOL_GPL(crypto_shash_update);
+
+static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
+{
+	struct crypto_shash *tfm = desc->tfm;
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned int ds = crypto_shash_digestsize(tfm);
+	u8 buf[shash_align_buffer_size(ds, alignmask)]
+		__attribute__ ((aligned));
+	int err;
+
+	err = shash->final(desc, buf);
+	memcpy(out, buf, ds);
+	return err;
+}
+
+int crypto_shash_final(struct shash_desc *desc, u8 *out)
+{
+	struct crypto_shash *tfm = desc->tfm;
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+
+	if ((unsigned long)out & alignmask)
+		return shash_final_unaligned(desc, out);
+
+	return shash->final(desc, out);
+}
+EXPORT_SYMBOL_GPL(crypto_shash_final);
+
+static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
+				 unsigned int len, u8 *out)
+{
+	return crypto_shash_update(desc, data, len) ?:
+	       crypto_shash_final(desc, out);
+}
+
+int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
+		       unsigned int len, u8 *out)
+{
+	struct crypto_shash *tfm = desc->tfm;
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+
+	if (((unsigned long)data | (unsigned long)out) & alignmask ||
+	    !shash->finup)
+		return shash_finup_unaligned(desc, data, len, out);
+
+	return shash->finup(desc, data, len, out);
+}
+EXPORT_SYMBOL_GPL(crypto_shash_finup);
+
+static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
+				  unsigned int len, u8 *out)
+{
+	return crypto_shash_init(desc) ?:
+	       crypto_shash_update(desc, data, len) ?:
+	       crypto_shash_final(desc, out);
+}
+
+int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
+			unsigned int len, u8 *out)
+{
+	struct crypto_shash *tfm = desc->tfm;
+	struct shash_alg *shash = crypto_shash_alg(tfm);
+	unsigned long alignmask = crypto_shash_alignmask(tfm);
+
+	if (((unsigned long)data | (unsigned long)out) & alignmask ||
+	    !shash->digest)
+		return shash_digest_unaligned(desc, data, len, out);
+
+	return shash->digest(desc, data, len, out);
+}
+EXPORT_SYMBOL_GPL(crypto_shash_digest);
+
+static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
+				 const struct crypto_type *frontend)
+{
+	if (frontend->type != CRYPTO_ALG_TYPE_SHASH)
+		return -EINVAL;
+	return 0;
+}
+
+static unsigned int crypto_shash_extsize(struct crypto_alg *alg,
+					 const struct crypto_type *frontend)
+{
+	return alg->cra_ctxsize;
+}
+
+static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
+	__attribute__ ((unused));
+static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
+{
+	struct shash_alg *salg = __crypto_shash_alg(alg);
+
+	seq_printf(m, "type         : shash\n");
+	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
+	seq_printf(m, "digestsize   : %u\n", salg->digestsize);
+	seq_printf(m, "descsize     : %u\n", salg->descsize);
+}
+
+static const struct crypto_type crypto_shash_type = {
+	.extsize = crypto_shash_extsize,
+	.init_tfm = crypto_shash_init_tfm,
+#ifdef CONFIG_PROC_FS
+	.show = crypto_shash_show,
+#endif
+	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
+	.maskset = CRYPTO_ALG_TYPE_MASK,
+	.type = CRYPTO_ALG_TYPE_SHASH,
+	.tfmsize = offsetof(struct crypto_shash, base),
+};
+
+struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
+					u32 mask)
+{
+	return __crypto_shash_cast(
+		crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask));
+}
+EXPORT_SYMBOL_GPL(crypto_alloc_shash);
+
+int crypto_register_shash(struct shash_alg *alg)
+{
+	struct crypto_alg *base = &alg->base;
+
+	if (alg->digestsize > PAGE_SIZE / 8 ||
+	    alg->descsize > PAGE_SIZE / 8)
+		return -EINVAL;
+
+	base->cra_type = &crypto_shash_type;
+	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
+	base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
+
+	return crypto_register_alg(base);
+}
+EXPORT_SYMBOL_GPL(crypto_register_shash);
+
+int crypto_unregister_shash(struct shash_alg *alg)
+{
+	return crypto_unregister_alg(&alg->base);
+}
+EXPORT_SYMBOL_GPL(crypto_unregister_shash);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Synchronous cryptographic hash type");