1 files changed, 405 insertions, 0 deletions

diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
new file mode 100644
index 000000000000..034c939bf91a
--- /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");