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[BLOCK] cryptoloop: Use block ciphers where applicable
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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>
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Herbert Xu committed Sep 21, 2006
1 parent cba8356 commit 69affe7
Showing 1 changed file with 54 additions and 106 deletions.
160 changes: 54 additions & 106 deletions drivers/block/cryptoloop.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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 */

Expand All @@ -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;
Expand All @@ -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) {
Expand All @@ -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;
Expand All @@ -194,32 +168,6 @@ cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
return 0;
}

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)
{
Expand All @@ -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;
}
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