1 files changed, 279 insertions, 2 deletions

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index f6f0833..a854df2 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -1,6 +1,6 @@
 /*
  * Asynchronous block chaining cipher operations.
- * 
+ *
  * This is the asynchronous version of blkcipher.c indicating completion
  * via a callback.
  *
@@ -8,7 +8,7 @@
  *
  * 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) 
+ * Software Foundation; either version 2 of the License, or (at your option)
  * any later version.
  *
  */
@@ -24,10 +24,287 @@
 #include <linux/slab.h>
 #include <linux/seq_file.h>
 
+#include <crypto/scatterwalk.h>
+
 #include "internal.h"
 
 static const char *skcipher_default_geniv __read_mostly;
 
+struct ablkcipher_buffer {
+	struct list_head	entry;
+	struct scatter_walk	dst;
+	unsigned int		len;
+	void			*data;
+};
+
+enum {
+	ABLKCIPHER_WALK_SLOW = 1 << 0,
+};
+
+static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
+{
+	scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
+}
+
+void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
+{
+	struct ablkcipher_buffer *p, *tmp;
+
+	list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
+		ablkcipher_buffer_write(p);
+		list_del(&p->entry);
+		kfree(p);
+	}
+}
+EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
+
+static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
+					  struct ablkcipher_buffer *p)
+{
+	p->dst = walk->out;
+	list_add_tail(&p->entry, &walk->buffers);
+}
+
+/* Get a spot of the specified length that does not straddle a page.
+ * The caller needs to ensure that there is enough space for this operation.
+ */
+static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
+{
+	u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
+	return max(start, end_page);
+}
+
+static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
+						unsigned int bsize)
+{
+	unsigned int n = bsize;
+
+	for (;;) {
+		unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
+
+		if (len_this_page > n)
+			len_this_page = n;
+		scatterwalk_advance(&walk->out, n);
+		if (n == len_this_page)
+			break;
+		n -= len_this_page;
+		scatterwalk_start(&walk->out, scatterwalk_sg_next(walk->out.sg));
+	}
+
+	return bsize;
+}
+
+static inline unsigned int ablkcipher_done_fast(struct ablkcipher_walk *walk,
+						unsigned int n)
+{
+	scatterwalk_advance(&walk->in, n);
+	scatterwalk_advance(&walk->out, n);
+
+	return n;
+}
+
+static int ablkcipher_walk_next(struct ablkcipher_request *req,
+				struct ablkcipher_walk *walk);
+
+int ablkcipher_walk_done(struct ablkcipher_request *req,
+			 struct ablkcipher_walk *walk, int err)
+{
+	struct crypto_tfm *tfm = req->base.tfm;
+	unsigned int nbytes = 0;
+
+	if (likely(err >= 0)) {
+		unsigned int n = walk->nbytes - err;
+
+		if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW)))
+			n = ablkcipher_done_fast(walk, n);
+		else if (WARN_ON(err)) {
+			err = -EINVAL;
+			goto err;
+		} else
+			n = ablkcipher_done_slow(walk, n);
+
+		nbytes = walk->total - n;
+		err = 0;
+	}
+
+	scatterwalk_done(&walk->in, 0, nbytes);
+	scatterwalk_done(&walk->out, 1, nbytes);
+
+err:
+	walk->total = nbytes;
+	walk->nbytes = nbytes;
+
+	if (nbytes) {
+		crypto_yield(req->base.flags);
+		return ablkcipher_walk_next(req, walk);
+	}
+
+	if (walk->iv != req->info)
+		memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
+	if (walk->iv_buffer)
+		kfree(walk->iv_buffer);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
+
+static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
+				       struct ablkcipher_walk *walk,
+				       unsigned int bsize,
+				       unsigned int alignmask,
+				       void **src_p, void **dst_p)
+{
+	unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
+	struct ablkcipher_buffer *p;
+	void *src, *dst, *base;
+	unsigned int n;
+
+	n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
+	n += (aligned_bsize * 3 - (alignmask + 1) +
+	      (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
+
+	p = kmalloc(n, GFP_ATOMIC);
+	if (!p)
+		return ablkcipher_walk_done(req, walk, -ENOMEM);
+
+	base = p + 1;
+
+	dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
+	src = dst = ablkcipher_get_spot(dst, bsize);
+
+	p->len = bsize;
+	p->data = dst;
+
+	scatterwalk_copychunks(src, &walk->in, bsize, 0);
+
+	ablkcipher_queue_write(walk, p);
+
+	walk->nbytes = bsize;
+	walk->flags |= ABLKCIPHER_WALK_SLOW;
+
+	*src_p = src;
+	*dst_p = dst;
+
+	return 0;
+}
+
+static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
+				     struct crypto_tfm *tfm,
+				     unsigned int alignmask)
+{
+	unsigned bs = walk->blocksize;
+	unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
+	unsigned aligned_bs = ALIGN(bs, alignmask + 1);
+	unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
+			    (alignmask + 1);
+	u8 *iv;
+
+	size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
+	walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
+	if (!walk->iv_buffer)
+		return -ENOMEM;
+
+	iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
+	iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
+	iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
+	iv = ablkcipher_get_spot(iv, ivsize);
+
+	walk->iv = memcpy(iv, walk->iv, ivsize);
+	return 0;
+}
+
+static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
+				       struct ablkcipher_walk *walk)
+{
+	walk->src.page = scatterwalk_page(&walk->in);
+	walk->src.offset = offset_in_page(walk->in.offset);
+	walk->dst.page = scatterwalk_page(&walk->out);
+	walk->dst.offset = offset_in_page(walk->out.offset);
+
+	return 0;
+}
+
+static int ablkcipher_walk_next(struct ablkcipher_request *req,
+				struct ablkcipher_walk *walk)
+{
+	struct crypto_tfm *tfm = req->base.tfm;
+	unsigned int alignmask, bsize, n;
+	void *src, *dst;
+	int err;
+
+	alignmask = crypto_tfm_alg_alignmask(tfm);
+	n = walk->total;
+	if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
+		req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
+		return ablkcipher_walk_done(req, walk, -EINVAL);
+	}
+
+	walk->flags &= ~ABLKCIPHER_WALK_SLOW;
+	src = dst = NULL;
+
+	bsize = min(walk->blocksize, n);
+	n = scatterwalk_clamp(&walk->in, n);
+	n = scatterwalk_clamp(&walk->out, n);
+
+	if (n < bsize ||
+	    !scatterwalk_aligned(&walk->in, alignmask) ||
+	    !scatterwalk_aligned(&walk->out, alignmask)) {
+		err = ablkcipher_next_slow(req, walk, bsize, alignmask,
+					   &src, &dst);
+		goto set_phys_lowmem;
+	}
+
+	walk->nbytes = n;
+
+	return ablkcipher_next_fast(req, walk);
+
+set_phys_lowmem:
+	if (err >= 0) {
+		walk->src.page = virt_to_page(src);
+		walk->dst.page = virt_to_page(dst);
+		walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
+		walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
+	}
+
+	return err;
+}
+
+static int ablkcipher_walk_first(struct ablkcipher_request *req,
+				 struct ablkcipher_walk *walk)
+{
+	struct crypto_tfm *tfm = req->base.tfm;
+	unsigned int alignmask;
+
+	alignmask = crypto_tfm_alg_alignmask(tfm);
+	if (WARN_ON_ONCE(in_irq()))
+		return -EDEADLK;
+
+	walk->nbytes = walk->total;
+	if (unlikely(!walk->total))
+		return 0;
+
+	walk->iv_buffer = NULL;
+	walk->iv = req->info;
+	if (unlikely(((unsigned long)walk->iv & alignmask))) {
+		int err = ablkcipher_copy_iv(walk, tfm, alignmask);
+		if (err)
+			return err;
+	}
+
+	scatterwalk_start(&walk->in, walk->in.sg);
+	scatterwalk_start(&walk->out, walk->out.sg);
+
+	return ablkcipher_walk_next(req, walk);
+}
+
+int ablkcipher_walk_phys(struct ablkcipher_request *req,
+			 struct ablkcipher_walk *walk)
+{
+	walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
+	return ablkcipher_walk_first(req, walk);
+}
+EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
+
 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 			    unsigned int keylen)
 {