[BLOCK] cryptoloop: Use block ciphers where applicable

This patch converts cryptoloop to use the new block cipher type where
applicable.  As a result the ECB-specific and CBC-specific transfer
functions have been merged.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 54 insertions, 106 deletions

diff --git a/drivers/block/cryptoloop.c b/drivers/block/cryptoloop.c
index 3d4261c39f16..40535036e893 100644
--- a/drivers/block/cryptoloop.c
+++ b/drivers/block/cryptoloop.c
@@ -40,11 +40,13 @@ static int
 cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info)
 {
         int err = -EINVAL;
+        int cipher_len;
+        int mode_len;
         char cms[LO_NAME_SIZE];                 /* cipher-mode string */
         char *cipher;
         char *mode;
         char *cmsp = cms;                       /* c-m string pointer */
-        struct crypto_tfm *tfm = NULL;
+        struct crypto_blkcipher *tfm;
 
         /* encryption breaks for non sector aligned offsets */
 
@@ -53,20 +55,39 @@ cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info)
 
         strncpy(cms, info->lo_crypt_name, LO_NAME_SIZE);
         cms[LO_NAME_SIZE - 1] = 0;
-        cipher = strsep(&cmsp, "-");
-        mode = strsep(&cmsp, "-");
-
-        if (mode == NULL || strcmp(mode, "cbc") == 0)
-                tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_CBC |
-                                               CRYPTO_TFM_REQ_MAY_SLEEP);
-        else if (strcmp(mode, "ecb") == 0)
-                tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_ECB |
-                                               CRYPTO_TFM_REQ_MAY_SLEEP);
-        if (tfm == NULL)
+
+        cipher = cmsp;
+        cipher_len = strcspn(cmsp, "-");
+
+        mode = cmsp + cipher_len;
+        mode_len = 0;
+        if (*mode) {
+                mode++;
+                mode_len = strcspn(mode, "-");
+        }
+
+        if (!mode_len) {
+                mode = "cbc";
+                mode_len = 3;
+        }
+
+        if (cipher_len + mode_len + 3 > LO_NAME_SIZE)
                 return -EINVAL;
 
-        err = tfm->crt_u.cipher.cit_setkey(tfm, info->lo_encrypt_key,
-                                           info->lo_encrypt_key_size);
+        memmove(cms, mode, mode_len);
+        cmsp = cms + mode_len;
+        *cmsp++ = '(';
+        memcpy(cmsp, info->lo_crypt_name, cipher_len);
+        cmsp += cipher_len;
+        *cmsp++ = ')';
+        *cmsp = 0;
+
+        tfm = crypto_alloc_blkcipher(cms, 0, CRYPTO_ALG_ASYNC);
+        if (IS_ERR(tfm))
+                return PTR_ERR(tfm);
+
+        err = crypto_blkcipher_setkey(tfm, info->lo_encrypt_key,
+                                      info->lo_encrypt_key_size);
         
         if (err != 0)
                 goto out_free_tfm;
@@ -75,99 +96,49 @@ cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info)
         return 0;
 
  out_free_tfm:
-        crypto_free_tfm(tfm);
+        crypto_free_blkcipher(tfm);
 
  out:
         return err;
 }
 
 
-typedef int (*encdec_ecb_t)(struct crypto_tfm *tfm,
+typedef int (*encdec_cbc_t)(struct blkcipher_desc *desc,
                         struct scatterlist *sg_out,
                         struct scatterlist *sg_in,
                         unsigned int nsg);
 
-
-static int
-cryptoloop_transfer_ecb(struct loop_device *lo, int cmd,
-                        struct page *raw_page, unsigned raw_off,
-                        struct page *loop_page, unsigned loop_off,
-                        int size, sector_t IV)
-{
-        struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
-        struct scatterlist sg_out = { NULL, };
-        struct scatterlist sg_in = { NULL, };
-
-        encdec_ecb_t encdecfunc;
-        struct page *in_page, *out_page;
-        unsigned in_offs, out_offs;
-
-        if (cmd == READ) {
-                in_page = raw_page;
-                in_offs = raw_off;
-                out_page = loop_page;
-                out_offs = loop_off;
-                encdecfunc = tfm->crt_u.cipher.cit_decrypt;
-        } else {
-                in_page = loop_page;
-                in_offs = loop_off;
-                out_page = raw_page;
-                out_offs = raw_off;
-                encdecfunc = tfm->crt_u.cipher.cit_encrypt;
-        }
-
-        while (size > 0) {
-                const int sz = min(size, LOOP_IV_SECTOR_SIZE);
-
-                sg_in.page = in_page;
-                sg_in.offset = in_offs;
-                sg_in.length = sz;
-
-                sg_out.page = out_page;
-                sg_out.offset = out_offs;
-                sg_out.length = sz;
-
-                encdecfunc(tfm, &sg_out, &sg_in, sz);
-
-                size -= sz;
-                in_offs += sz;
-                out_offs += sz;
-        }
-
-        return 0;
-}
-
-typedef int (*encdec_cbc_t)(struct crypto_tfm *tfm,
-                        struct scatterlist *sg_out,
-                        struct scatterlist *sg_in,
-                        unsigned int nsg, u8 *iv);
-
 static int
-cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
-                        struct page *raw_page, unsigned raw_off,
-                        struct page *loop_page, unsigned loop_off,
-                        int size, sector_t IV)
+cryptoloop_transfer(struct loop_device *lo, int cmd,
+                    struct page *raw_page, unsigned raw_off,
+                    struct page *loop_page, unsigned loop_off,
+                    int size, sector_t IV)
 {
-        struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+        struct crypto_blkcipher *tfm = lo->key_data;
+        struct blkcipher_desc desc = {
+                .tfm = tfm,
+                .flags = CRYPTO_TFM_REQ_MAY_SLEEP,
+        };
         struct scatterlist sg_out = { NULL, };
         struct scatterlist sg_in = { NULL, };
 
         encdec_cbc_t encdecfunc;
         struct page *in_page, *out_page;
         unsigned in_offs, out_offs;
+        int err;
 
         if (cmd == READ) {
                 in_page = raw_page;
                 in_offs = raw_off;
                 out_page = loop_page;
                 out_offs = loop_off;
-                encdecfunc = tfm->crt_u.cipher.cit_decrypt_iv;
+                encdecfunc = crypto_blkcipher_crt(tfm)->decrypt;
         } else {
                 in_page = loop_page;
                 in_offs = loop_off;
                 out_page = raw_page;
                 out_offs = raw_off;
-                encdecfunc = tfm->crt_u.cipher.cit_encrypt_iv;
+                encdecfunc = crypto_blkcipher_crt(tfm)->encrypt;
         }
 
         while (size > 0) {
@@ -183,7 +154,10 @@ cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
                 sg_out.offset = out_offs;
                 sg_out.length = sz;
 
-                encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);
+                desc.info = iv;
+                err = encdecfunc(&desc, &sg_out, &sg_in, sz);
+                if (err)
+                        return err;
 
                 IV++;
                 size -= sz;
@@ -195,32 +169,6 @@ cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
 }
 
 static int
-cryptoloop_transfer(struct loop_device *lo, int cmd,
-                    struct page *raw_page, unsigned raw_off,
-                    struct page *loop_page, unsigned loop_off,
-                    int size, sector_t IV)
-{
-        struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
-        if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_ECB)
-        {
-                lo->transfer = cryptoloop_transfer_ecb;
-                return cryptoloop_transfer_ecb(lo, cmd, raw_page, raw_off,
-                                               loop_page, loop_off, size, IV);
-        }       
-        if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_CBC)
-        {       
-                lo->transfer = cryptoloop_transfer_cbc;
-                return cryptoloop_transfer_cbc(lo, cmd, raw_page, raw_off,
-                                               loop_page, loop_off, size, IV);
-        }
-        
-        /*  This is not supposed to happen */
-
-        printk( KERN_ERR "cryptoloop: unsupported cipher mode in cryptoloop_transfer!\n");
-        return -EINVAL;
-}
-
-static int
 cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
 {
         return -EINVAL;
@@ -229,9 +177,9 @@ cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
 static int
 cryptoloop_release(struct loop_device *lo)
 {
-        struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+        struct crypto_blkcipher *tfm = lo->key_data;
         if (tfm != NULL) {
-                crypto_free_tfm(tfm);
+                crypto_free_blkcipher(tfm);
                 lo->key_data = NULL;
                 return 0;
         }