1 files changed, 321 insertions, 33 deletions

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 16f6ba896fb6..1d010e2a1b1a 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -10,64 +10,119 @@
  */
 
 #include <crypto/scatterwalk.h>
+#include <linux/crypto.h>
+#include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/scatterlist.h>
+#include <linux/slab.h>
 
-static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
+enum {
+	SKCIPHER_WALK_SLOW = 1 << 0,
+	SKCIPHER_WALK_COPY = 1 << 1,
+	SKCIPHER_WALK_DIFF = 1 << 2,
+	SKCIPHER_WALK_SLEEP = 1 << 3,
+};
+
+static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk)
+{
+	return walk->flags & SKCIPHER_WALK_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
+}
+
+void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes)
 {
-	void *src = out ? buf : sgdata;
-	void *dst = out ? sgdata : buf;
+	struct scatterlist *sg = walk->sg;
+
+	nbytes += walk->offset - sg->offset;
 
-	memcpy(dst, src, nbytes);
+	while (nbytes > sg->length) {
+		nbytes -= sg->length;
+		sg = sg_next(sg);
+	}
+	walk->sg = sg;
+	walk->offset = sg->offset + nbytes;
 }
+EXPORT_SYMBOL_GPL(scatterwalk_skip);
 
-void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
-			    size_t nbytes, int out)
+inline void memcpy_from_scatterwalk(void *buf, struct scatter_walk *walk,
+				    unsigned int nbytes)
 {
-	for (;;) {
-		unsigned int len_this_page = scatterwalk_pagelen(walk);
-		u8 *vaddr;
+	do {
+		unsigned int to_copy;
 
-		if (len_this_page > nbytes)
-			len_this_page = nbytes;
+		to_copy = scatterwalk_next(walk, nbytes);
+		memcpy(buf, walk->addr, to_copy);
+		scatterwalk_done_src(walk, to_copy);
+		buf += to_copy;
+		nbytes -= to_copy;
+	} while (nbytes);
+}
+EXPORT_SYMBOL_GPL(memcpy_from_scatterwalk);
 
-		if (out != 2) {
-			vaddr = scatterwalk_map(walk);
-			memcpy_dir(buf, vaddr, len_this_page, out);
-			scatterwalk_unmap(vaddr);
-		}
+inline void memcpy_to_scatterwalk(struct scatter_walk *walk, const void *buf,
+				  unsigned int nbytes)
+{
+	do {
+		unsigned int to_copy;
 
-		scatterwalk_advance(walk, len_this_page);
+		to_copy = scatterwalk_next(walk, nbytes);
+		memcpy(walk->addr, buf, to_copy);
+		scatterwalk_done_dst(walk, to_copy);
+		buf += to_copy;
+		nbytes -= to_copy;
+	} while (nbytes);
+}
+EXPORT_SYMBOL_GPL(memcpy_to_scatterwalk);
 
-		if (nbytes == len_this_page)
-			break;
+void memcpy_from_sglist(void *buf, struct scatterlist *sg,
+			unsigned int start, unsigned int nbytes)
+{
+	struct scatter_walk walk;
 
-		buf += len_this_page;
-		nbytes -= len_this_page;
+	if (unlikely(nbytes == 0)) /* in case sg == NULL */
+		return;
 
-		scatterwalk_pagedone(walk, out & 1, 1);
-	}
+	scatterwalk_start_at_pos(&walk, sg, start);
+	memcpy_from_scatterwalk(buf, &walk, nbytes);
 }
-EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
+EXPORT_SYMBOL_GPL(memcpy_from_sglist);
 
-void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
-			      unsigned int start, unsigned int nbytes, int out)
+void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
+		      const void *buf, unsigned int nbytes)
 {
 	struct scatter_walk walk;
-	struct scatterlist tmp[2];
 
-	if (!nbytes)
+	if (unlikely(nbytes == 0)) /* in case sg == NULL */
 		return;
 
-	sg = scatterwalk_ffwd(tmp, sg, start);
+	scatterwalk_start_at_pos(&walk, sg, start);
+	memcpy_to_scatterwalk(&walk, buf, nbytes);
+}
+EXPORT_SYMBOL_GPL(memcpy_to_sglist);
+
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+		   unsigned int nbytes)
+{
+	struct skcipher_walk walk = {};
+
+	if (unlikely(nbytes == 0)) /* in case sg == NULL */
+		return;
+
+	walk.total = nbytes;
+
+	scatterwalk_start(&walk.in, src);
+	scatterwalk_start(&walk.out, dst);
 
-	scatterwalk_start(&walk, sg);
-	scatterwalk_copychunks(buf, &walk, nbytes, out);
-	scatterwalk_done(&walk, out, 0);
+	skcipher_walk_first(&walk, true);
+	do {
+		if (walk.src.virt.addr != walk.dst.virt.addr)
+			memcpy(walk.dst.virt.addr, walk.src.virt.addr,
+			       walk.nbytes);
+		skcipher_walk_done(&walk, 0);
+	} while (walk.nbytes);
 }
-EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
+EXPORT_SYMBOL_GPL(memcpy_sglist);
 
 struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
 				     struct scatterlist *src,
@@ -91,3 +146,236 @@ struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
 	return dst;
 }
 EXPORT_SYMBOL_GPL(scatterwalk_ffwd);
+
+static int skcipher_next_slow(struct skcipher_walk *walk, unsigned int bsize)
+{
+	unsigned alignmask = walk->alignmask;
+	unsigned n;
+	void *buffer;
+
+	if (!walk->buffer)
+		walk->buffer = walk->page;
+	buffer = walk->buffer;
+	if (!buffer) {
+		/* Min size for a buffer of bsize bytes aligned to alignmask */
+		n = bsize + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
+
+		buffer = kzalloc(n, skcipher_walk_gfp(walk));
+		if (!buffer)
+			return skcipher_walk_done(walk, -ENOMEM);
+		walk->buffer = buffer;
+	}
+
+	buffer = PTR_ALIGN(buffer, alignmask + 1);
+	memcpy_from_scatterwalk(buffer, &walk->in, bsize);
+	walk->out.__addr = buffer;
+	walk->in.__addr = walk->out.addr;
+
+	walk->nbytes = bsize;
+	walk->flags |= SKCIPHER_WALK_SLOW;
+
+	return 0;
+}
+
+static int skcipher_next_copy(struct skcipher_walk *walk)
+{
+	void *tmp = walk->page;
+
+	scatterwalk_map(&walk->in);
+	memcpy(tmp, walk->in.addr, walk->nbytes);
+	scatterwalk_unmap(&walk->in);
+	/*
+	 * walk->in is advanced later when the number of bytes actually
+	 * processed (which might be less than walk->nbytes) is known.
+	 */
+
+	walk->in.__addr = tmp;
+	walk->out.__addr = tmp;
+	return 0;
+}
+
+static int skcipher_next_fast(struct skcipher_walk *walk)
+{
+	unsigned long diff;
+
+	diff = offset_in_page(walk->in.offset) -
+	       offset_in_page(walk->out.offset);
+	diff |= (u8 *)(sg_page(walk->in.sg) + (walk->in.offset >> PAGE_SHIFT)) -
+		(u8 *)(sg_page(walk->out.sg) + (walk->out.offset >> PAGE_SHIFT));
+
+	scatterwalk_map(&walk->out);
+	walk->in.__addr = walk->out.__addr;
+
+	if (diff) {
+		walk->flags |= SKCIPHER_WALK_DIFF;
+		scatterwalk_map(&walk->in);
+	}
+
+	return 0;
+}
+
+static int skcipher_walk_next(struct skcipher_walk *walk)
+{
+	unsigned int bsize;
+	unsigned int n;
+
+	n = walk->total;
+	bsize = min(walk->stride, max(n, walk->blocksize));
+	n = scatterwalk_clamp(&walk->in, n);
+	n = scatterwalk_clamp(&walk->out, n);
+
+	if (unlikely(n < bsize)) {
+		if (unlikely(walk->total < walk->blocksize))
+			return skcipher_walk_done(walk, -EINVAL);
+
+slow_path:
+		return skcipher_next_slow(walk, bsize);
+	}
+	walk->nbytes = n;
+
+	if (unlikely((walk->in.offset | walk->out.offset) & walk->alignmask)) {
+		if (!walk->page) {
+			gfp_t gfp = skcipher_walk_gfp(walk);
+
+			walk->page = (void *)__get_free_page(gfp);
+			if (!walk->page)
+				goto slow_path;
+		}
+		walk->flags |= SKCIPHER_WALK_COPY;
+		return skcipher_next_copy(walk);
+	}
+
+	return skcipher_next_fast(walk);
+}
+
+static int skcipher_copy_iv(struct skcipher_walk *walk)
+{
+	unsigned alignmask = walk->alignmask;
+	unsigned ivsize = walk->ivsize;
+	unsigned aligned_stride = ALIGN(walk->stride, alignmask + 1);
+	unsigned size;
+	u8 *iv;
+
+	/* Min size for a buffer of stride + ivsize, aligned to alignmask */
+	size = aligned_stride + ivsize +
+	       (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
+
+	walk->buffer = kmalloc(size, skcipher_walk_gfp(walk));
+	if (!walk->buffer)
+		return -ENOMEM;
+
+	iv = PTR_ALIGN(walk->buffer, alignmask + 1) + aligned_stride;
+
+	walk->iv = memcpy(iv, walk->iv, walk->ivsize);
+	return 0;
+}
+
+int skcipher_walk_first(struct skcipher_walk *walk, bool atomic)
+{
+	if (WARN_ON_ONCE(in_hardirq()))
+		return -EDEADLK;
+
+	walk->flags = atomic ? 0 : SKCIPHER_WALK_SLEEP;
+
+	walk->buffer = NULL;
+	if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
+		int err = skcipher_copy_iv(walk);
+		if (err)
+			return err;
+	}
+
+	walk->page = NULL;
+
+	return skcipher_walk_next(walk);
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_first);
+
+/**
+ * skcipher_walk_done() - finish one step of a skcipher_walk
+ * @walk: the skcipher_walk
+ * @res: number of bytes *not* processed (>= 0) from walk->nbytes,
+ *	 or a -errno value to terminate the walk due to an error
+ *
+ * This function cleans up after one step of walking through the source and
+ * destination scatterlists, and advances to the next step if applicable.
+ * walk->nbytes is set to the number of bytes available in the next step,
+ * walk->total is set to the new total number of bytes remaining, and
+ * walk->{src,dst}.virt.addr is set to the next pair of data pointers.  If there
+ * is no more data, or if an error occurred (i.e. -errno return), then
+ * walk->nbytes and walk->total are set to 0 and all resources owned by the
+ * skcipher_walk are freed.
+ *
+ * Return: 0 or a -errno value.  If @res was a -errno value then it will be
+ *	   returned, but other errors may occur too.
+ */
+int skcipher_walk_done(struct skcipher_walk *walk, int res)
+{
+	unsigned int n = walk->nbytes; /* num bytes processed this step */
+	unsigned int total = 0; /* new total remaining */
+
+	if (!n)
+		goto finish;
+
+	if (likely(res >= 0)) {
+		n -= res; /* subtract num bytes *not* processed */
+		total = walk->total - n;
+	}
+
+	if (likely(!(walk->flags & (SKCIPHER_WALK_SLOW |
+				    SKCIPHER_WALK_COPY |
+				    SKCIPHER_WALK_DIFF)))) {
+		scatterwalk_advance(&walk->in, n);
+	} else if (walk->flags & SKCIPHER_WALK_DIFF) {
+		scatterwalk_done_src(&walk->in, n);
+	} else if (walk->flags & SKCIPHER_WALK_COPY) {
+		scatterwalk_advance(&walk->in, n);
+		scatterwalk_map(&walk->out);
+		memcpy(walk->out.addr, walk->page, n);
+	} else { /* SKCIPHER_WALK_SLOW */
+		if (res > 0) {
+			/*
+			 * Didn't process all bytes.  Either the algorithm is
+			 * broken, or this was the last step and it turned out
+			 * the message wasn't evenly divisible into blocks but
+			 * the algorithm requires it.
+			 */
+			res = -EINVAL;
+			total = 0;
+		} else
+			memcpy_to_scatterwalk(&walk->out, walk->out.addr, n);
+		goto dst_done;
+	}
+
+	scatterwalk_done_dst(&walk->out, n);
+dst_done:
+
+	if (res > 0)
+		res = 0;
+
+	walk->total = total;
+	walk->nbytes = 0;
+
+	if (total) {
+		if (walk->flags & SKCIPHER_WALK_SLEEP)
+			cond_resched();
+		walk->flags &= ~(SKCIPHER_WALK_SLOW | SKCIPHER_WALK_COPY |
+				 SKCIPHER_WALK_DIFF);
+		return skcipher_walk_next(walk);
+	}
+
+finish:
+	/* Short-circuit for the common/fast path. */
+	if (!((unsigned long)walk->buffer | (unsigned long)walk->page))
+		goto out;
+
+	if (walk->iv != walk->oiv)
+		memcpy(walk->oiv, walk->iv, walk->ivsize);
+	if (walk->buffer != walk->page)
+		kfree(walk->buffer);
+	if (walk->page)
+		free_page((unsigned long)walk->page);
+
+out:
+	return res;
+}
+EXPORT_SYMBOL_GPL(skcipher_walk_done);