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-rw-r--r--crypto/cbc.c109
1 files changed, 25 insertions, 84 deletions
diff --git a/crypto/cbc.c b/crypto/cbc.c
index 1f2649e..6affff8 100644
--- a/crypto/cbc.c
+++ b/crypto/cbc.c
@@ -14,13 +14,13 @@
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
+#include <linux/log2.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
struct crypto_cbc_ctx {
struct crypto_cipher *child;
- void (*xor)(u8 *dst, const u8 *src, unsigned int bs);
};
static int crypto_cbc_setkey(struct crypto_tfm *parent, const u8 *key,
@@ -41,9 +41,7 @@ static int crypto_cbc_setkey(struct crypto_tfm *parent, const u8 *key,
static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
- struct crypto_cipher *tfm,
- void (*xor)(u8 *, const u8 *,
- unsigned int))
+ struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
@@ -54,7 +52,7 @@ static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
u8 *iv = walk->iv;
do {
- xor(iv, src, bsize);
+ crypto_xor(iv, src, bsize);
fn(crypto_cipher_tfm(tfm), dst, iv);
memcpy(iv, dst, bsize);
@@ -67,9 +65,7 @@ static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
- struct crypto_cipher *tfm,
- void (*xor)(u8 *, const u8 *,
- unsigned int))
+ struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
@@ -79,7 +75,7 @@ static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
u8 *iv = walk->iv;
do {
- xor(src, iv, bsize);
+ crypto_xor(src, iv, bsize);
fn(crypto_cipher_tfm(tfm), src, src);
iv = src;
@@ -99,7 +95,6 @@ static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
- void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -107,11 +102,9 @@ static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
while ((nbytes = walk.nbytes)) {
if (walk.src.virt.addr == walk.dst.virt.addr)
- nbytes = crypto_cbc_encrypt_inplace(desc, &walk, child,
- xor);
+ nbytes = crypto_cbc_encrypt_inplace(desc, &walk, child);
else
- nbytes = crypto_cbc_encrypt_segment(desc, &walk, child,
- xor);
+ nbytes = crypto_cbc_encrypt_segment(desc, &walk, child);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
@@ -120,9 +113,7 @@ static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
- struct crypto_cipher *tfm,
- void (*xor)(u8 *, const u8 *,
- unsigned int))
+ struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_decrypt;
@@ -134,7 +125,7 @@ static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
do {
fn(crypto_cipher_tfm(tfm), dst, src);
- xor(dst, iv, bsize);
+ crypto_xor(dst, iv, bsize);
iv = src;
src += bsize;
@@ -148,34 +139,29 @@ static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
- struct crypto_cipher *tfm,
- void (*xor)(u8 *, const u8 *,
- unsigned int))
+ struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_decrypt;
int bsize = crypto_cipher_blocksize(tfm);
- unsigned long alignmask = crypto_cipher_alignmask(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
- u8 stack[bsize + alignmask];
- u8 *first_iv = (u8 *)ALIGN((unsigned long)stack, alignmask + 1);
-
- memcpy(first_iv, walk->iv, bsize);
+ u8 last_iv[bsize];
/* Start of the last block. */
- src += nbytes - nbytes % bsize - bsize;
- memcpy(walk->iv, src, bsize);
+ src += nbytes - (nbytes & (bsize - 1)) - bsize;
+ memcpy(last_iv, src, bsize);
for (;;) {
fn(crypto_cipher_tfm(tfm), src, src);
if ((nbytes -= bsize) < bsize)
break;
- xor(src, src - bsize, bsize);
+ crypto_xor(src, src - bsize, bsize);
src -= bsize;
}
- xor(src, first_iv, bsize);
+ crypto_xor(src, walk->iv, bsize);
+ memcpy(walk->iv, last_iv, bsize);
return nbytes;
}
@@ -188,7 +174,6 @@ static int crypto_cbc_decrypt(struct blkcipher_desc *desc,
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
- void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -196,48 +181,15 @@ static int crypto_cbc_decrypt(struct blkcipher_desc *desc,
while ((nbytes = walk.nbytes)) {
if (walk.src.virt.addr == walk.dst.virt.addr)
- nbytes = crypto_cbc_decrypt_inplace(desc, &walk, child,
- xor);
+ nbytes = crypto_cbc_decrypt_inplace(desc, &walk, child);
else
- nbytes = crypto_cbc_decrypt_segment(desc, &walk, child,
- xor);
+ nbytes = crypto_cbc_decrypt_segment(desc, &walk, child);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
return err;
}
-static void xor_byte(u8 *a, const u8 *b, unsigned int bs)
-{
- do {
- *a++ ^= *b++;
- } while (--bs);
-}
-
-static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)
-{
- u32 *a = (u32 *)dst;
- u32 *b = (u32 *)src;
-
- do {
- *a++ ^= *b++;
- } while ((bs -= 4));
-}
-
-static void xor_64(u8 *a, const u8 *b, unsigned int bs)
-{
- ((u32 *)a)[0] ^= ((u32 *)b)[0];
- ((u32 *)a)[1] ^= ((u32 *)b)[1];
-}
-
-static void xor_128(u8 *a, const u8 *b, unsigned int bs)
-{
- ((u32 *)a)[0] ^= ((u32 *)b)[0];
- ((u32 *)a)[1] ^= ((u32 *)b)[1];
- ((u32 *)a)[2] ^= ((u32 *)b)[2];
- ((u32 *)a)[3] ^= ((u32 *)b)[3];
-}
-
static int crypto_cbc_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
@@ -245,22 +197,6 @@ static int crypto_cbc_init_tfm(struct crypto_tfm *tfm)
struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
- switch (crypto_tfm_alg_blocksize(tfm)) {
- case 8:
- ctx->xor = xor_64;
- break;
-
- case 16:
- ctx->xor = xor_128;
- break;
-
- default:
- if (crypto_tfm_alg_blocksize(tfm) % 4)
- ctx->xor = xor_byte;
- else
- ctx->xor = xor_quad;
- }
-
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
@@ -290,6 +226,10 @@ static struct crypto_instance *crypto_cbc_alloc(struct rtattr **tb)
if (IS_ERR(alg))
return ERR_PTR(PTR_ERR(alg));
+ inst = ERR_PTR(-EINVAL);
+ if (!is_power_of_2(alg->cra_blocksize))
+ goto out_put_alg;
+
inst = crypto_alloc_instance("cbc", alg);
if (IS_ERR(inst))
goto out_put_alg;
@@ -300,8 +240,9 @@ static struct crypto_instance *crypto_cbc_alloc(struct rtattr **tb)
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_blkcipher_type;
- if (!(alg->cra_blocksize % 4))
- inst->alg.cra_alignmask |= 3;
+ /* We access the data as u32s when xoring. */
+ inst->alg.cra_alignmask |= __alignof__(u32) - 1;
+
inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
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