1 files changed, 277 insertions, 0 deletions

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index fe980dae1727..98a66103f4f2 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -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)
+                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)
 {