1 files changed, 405 insertions, 0 deletions

diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
new file mode 100644
index 0000000..034c939
--- /dev/null
+++ b/crypto/blkcipher.c
@@ -0,0 +1,405 @@
+/*
+ * Block chaining cipher operations.
+ * 
+ * Generic encrypt/decrypt wrapper for ciphers, handles operations across
+ * multiple page boundaries by using temporary blocks.  In user context,
+ * the kernel is given a chance to schedule us once per page.
+ *
+ * Copyright (c) 2006 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 <linux/crypto.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "internal.h"
+#include "scatterwalk.h"
+
+enum {
+	BLKCIPHER_WALK_PHYS = 1 << 0,
+	BLKCIPHER_WALK_SLOW = 1 << 1,
+	BLKCIPHER_WALK_COPY = 1 << 2,
+	BLKCIPHER_WALK_DIFF = 1 << 3,
+};
+
+static int blkcipher_walk_next(struct blkcipher_desc *desc,
+			       struct blkcipher_walk *walk);
+static int blkcipher_walk_first(struct blkcipher_desc *desc,
+				struct blkcipher_walk *walk);
+
+static inline void blkcipher_map_src(struct blkcipher_walk *walk)
+{
+	walk->src.virt.addr = scatterwalk_map(&walk->in, 0);
+}
+
+static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
+{
+	walk->dst.virt.addr = scatterwalk_map(&walk->out, 1);
+}
+
+static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
+{
+	scatterwalk_unmap(walk->src.virt.addr, 0);
+}
+
+static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
+{
+	scatterwalk_unmap(walk->dst.virt.addr, 1);
+}
+
+static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
+{
+	if (offset_in_page(start + len) < len)
+		return (u8 *)((unsigned long)(start + len) & PAGE_MASK);
+	return start;
+}
+
+static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm,
+					       struct blkcipher_walk *walk,
+					       unsigned int bsize)
+{
+	u8 *addr;
+	unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
+
+	addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
+	addr = blkcipher_get_spot(addr, bsize);
+	scatterwalk_copychunks(addr, &walk->out, bsize, 1);
+	return bsize;
+}
+
+static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
+					       unsigned int n)
+{
+	n = walk->nbytes - n;
+
+	if (walk->flags & BLKCIPHER_WALK_COPY) {
+		blkcipher_map_dst(walk);
+		memcpy(walk->dst.virt.addr, walk->page, n);
+		blkcipher_unmap_dst(walk);
+	} else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
+		blkcipher_unmap_src(walk);
+		if (walk->flags & BLKCIPHER_WALK_DIFF)
+			blkcipher_unmap_dst(walk);
+	}
+
+	scatterwalk_advance(&walk->in, n);
+	scatterwalk_advance(&walk->out, n);
+
+	return n;
+}
+
+int blkcipher_walk_done(struct blkcipher_desc *desc,
+			struct blkcipher_walk *walk, int err)
+{
+	struct crypto_blkcipher *tfm = desc->tfm;
+	unsigned int nbytes = 0;
+
+	if (likely(err >= 0)) {
+		unsigned int bsize = crypto_blkcipher_blocksize(tfm);
+		unsigned int n;
+
+		if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
+			n = blkcipher_done_fast(walk, err);
+		else
+			n = blkcipher_done_slow(tfm, walk, bsize);
+
+		nbytes = walk->total - n;
+		err = 0;
+	}
+
+	scatterwalk_done(&walk->in, 0, nbytes);
+	scatterwalk_done(&walk->out, 1, nbytes);
+
+	walk->total = nbytes;
+	walk->nbytes = nbytes;
+
+	if (nbytes) {
+		crypto_yield(desc->flags);
+		return blkcipher_walk_next(desc, walk);
+	}
+
+	if (walk->iv != desc->info)
+		memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
+	if (walk->buffer != walk->page)
+		kfree(walk->buffer);
+	if (walk->page)
+		free_page((unsigned long)walk->page);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_done);
+
+static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
+				      struct blkcipher_walk *walk,
+				      unsigned int bsize,
+				      unsigned int alignmask)
+{
+	unsigned int n;
+
+	if (walk->buffer)
+		goto ok;
+
+	walk->buffer = walk->page;
+	if (walk->buffer)
+		goto ok;
+
+	n = bsize * 2 + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
+	walk->buffer = kmalloc(n, GFP_ATOMIC);
+	if (!walk->buffer)
+		return blkcipher_walk_done(desc, walk, -ENOMEM);
+
+ok:
+	walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
+					  alignmask + 1);
+	walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
+	walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + bsize,
+						 bsize);
+
+	scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
+
+	walk->nbytes = bsize;
+	walk->flags |= BLKCIPHER_WALK_SLOW;
+
+	return 0;
+}
+
+static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
+{
+	u8 *tmp = walk->page;
+
+	blkcipher_map_src(walk);
+	memcpy(tmp, walk->src.virt.addr, walk->nbytes);
+	blkcipher_unmap_src(walk);
+
+	walk->src.virt.addr = tmp;
+	walk->dst.virt.addr = tmp;
+
+	return 0;
+}
+
+static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
+				      struct blkcipher_walk *walk)
+{
+	unsigned long diff;
+
+	walk->src.phys.page = scatterwalk_page(&walk->in);
+	walk->src.phys.offset = offset_in_page(walk->in.offset);
+	walk->dst.phys.page = scatterwalk_page(&walk->out);
+	walk->dst.phys.offset = offset_in_page(walk->out.offset);
+
+	if (walk->flags & BLKCIPHER_WALK_PHYS)
+		return 0;
+
+	diff = walk->src.phys.offset - walk->dst.phys.offset;
+	diff |= walk->src.virt.page - walk->dst.virt.page;
+
+	blkcipher_map_src(walk);
+	walk->dst.virt.addr = walk->src.virt.addr;
+
+	if (diff) {
+		walk->flags |= BLKCIPHER_WALK_DIFF;
+		blkcipher_map_dst(walk);
+	}
+
+	return 0;
+}
+
+static int blkcipher_walk_next(struct blkcipher_desc *desc,
+			       struct blkcipher_walk *walk)
+{
+	struct crypto_blkcipher *tfm = desc->tfm;
+	unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
+	unsigned int bsize = crypto_blkcipher_blocksize(tfm);
+	unsigned int n;
+	int err;
+
+	n = walk->total;
+	if (unlikely(n < bsize)) {
+		desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
+		return blkcipher_walk_done(desc, walk, -EINVAL);
+	}
+
+	walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
+			 BLKCIPHER_WALK_DIFF);
+	if (!scatterwalk_aligned(&walk->in, alignmask) ||
+	    !scatterwalk_aligned(&walk->out, alignmask)) {
+		walk->flags |= BLKCIPHER_WALK_COPY;
+		if (!walk->page) {
+			walk->page = (void *)__get_free_page(GFP_ATOMIC);
+			if (!walk->page)
+				n = 0;
+		}
+	}
+
+	n = scatterwalk_clamp(&walk->in, n);
+	n = scatterwalk_clamp(&walk->out, n);
+
+	if (unlikely(n < bsize)) {
+		err = blkcipher_next_slow(desc, walk, bsize, alignmask);
+		goto set_phys_lowmem;
+	}
+
+	walk->nbytes = n;
+	if (walk->flags & BLKCIPHER_WALK_COPY) {
+		err = blkcipher_next_copy(walk);
+		goto set_phys_lowmem;
+	}
+
+	return blkcipher_next_fast(desc, walk);
+
+set_phys_lowmem:
+	if (walk->flags & BLKCIPHER_WALK_PHYS) {
+		walk->src.phys.page = virt_to_page(walk->src.virt.addr);
+		walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
+		walk->src.phys.offset &= PAGE_SIZE - 1;
+		walk->dst.phys.offset &= PAGE_SIZE - 1;
+	}
+	return err;
+}
+
+static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
+				    struct crypto_blkcipher *tfm,
+				    unsigned int alignmask)
+{
+	unsigned bs = crypto_blkcipher_blocksize(tfm);
+	unsigned int ivsize = crypto_blkcipher_ivsize(tfm);
+	unsigned int size = bs * 2 + ivsize + max(bs, ivsize) - (alignmask + 1);
+	u8 *iv;
+
+	size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
+	walk->buffer = kmalloc(size, GFP_ATOMIC);
+	if (!walk->buffer)
+		return -ENOMEM;
+
+	iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
+	iv = blkcipher_get_spot(iv, bs) + bs;
+	iv = blkcipher_get_spot(iv, bs) + bs;
+	iv = blkcipher_get_spot(iv, ivsize);
+
+	walk->iv = memcpy(iv, walk->iv, ivsize);
+	return 0;
+}
+
+int blkcipher_walk_virt(struct blkcipher_desc *desc,
+			struct blkcipher_walk *walk)
+{
+	walk->flags &= ~BLKCIPHER_WALK_PHYS;
+	return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
+
+int blkcipher_walk_phys(struct blkcipher_desc *desc,
+			struct blkcipher_walk *walk)
+{
+	walk->flags |= BLKCIPHER_WALK_PHYS;
+	return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
+
+static int blkcipher_walk_first(struct blkcipher_desc *desc,
+				struct blkcipher_walk *walk)
+{
+	struct crypto_blkcipher *tfm = desc->tfm;
+	unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
+
+	walk->nbytes = walk->total;
+	if (unlikely(!walk->total))
+		return 0;
+
+	walk->buffer = NULL;
+	walk->iv = desc->info;
+	if (unlikely(((unsigned long)walk->iv & alignmask))) {
+		int err = blkcipher_copy_iv(walk, tfm, alignmask);
+		if (err)
+			return err;
+	}
+
+	scatterwalk_start(&walk->in, walk->in.sg);
+	scatterwalk_start(&walk->out, walk->out.sg);
+	walk->page = NULL;
+
+	return blkcipher_walk_next(desc, walk);
+}
+
+static int setkey(struct crypto_tfm *tfm, const u8 *key,
+		  unsigned int keylen)
+{
+	struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
+
+	if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
+		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	return cipher->setkey(tfm, key, keylen);
+}
+
+static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg)
+{
+	struct blkcipher_alg *cipher = &alg->cra_blkcipher;
+	unsigned int len = alg->cra_ctxsize;
+
+	if (cipher->ivsize) {
+		len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
+		len += cipher->ivsize;
+	}
+
+	return len;
+}
+
+static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm)
+{
+	struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
+	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
+	unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
+	unsigned long addr;
+
+	if (alg->ivsize > PAGE_SIZE / 8)
+		return -EINVAL;
+
+	crt->setkey = setkey;
+	crt->encrypt = alg->encrypt;
+	crt->decrypt = alg->decrypt;
+
+	addr = (unsigned long)crypto_tfm_ctx(tfm);
+	addr = ALIGN(addr, align);
+	addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
+	crt->iv = (void *)addr;
+
+	return 0;
+}
+
+static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
+	__attribute_used__;
+static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
+{
+	seq_printf(m, "type         : blkcipher\n");
+	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
+	seq_printf(m, "min keysize  : %u\n", alg->cra_blkcipher.min_keysize);
+	seq_printf(m, "max keysize  : %u\n", alg->cra_blkcipher.max_keysize);
+	seq_printf(m, "ivsize       : %u\n", alg->cra_blkcipher.ivsize);
+}
+
+const struct crypto_type crypto_blkcipher_type = {
+	.ctxsize = crypto_blkcipher_ctxsize,
+	.init = crypto_init_blkcipher_ops,
+#ifdef CONFIG_PROC_FS
+	.show = crypto_blkcipher_show,
+#endif
+};
+EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Generic block chaining cipher type");