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crypto: s390 - fix des and des3_ede ctr concurrency issue

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In s390 des and 3des ctr mode there is one preallocated page
used to speed up the en/decryption. This page is not protected
against concurrent usage and thus there is a potential of data
corruption with multiple threads.

The fix introduces locking/unlocking the ctr page and a slower
fallback solution at concurrency situations.

Cc: stable@vger.kernel.org
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Harald Freudenberger 2014-01-22 13:01:33 +01:00 committed by Herbert Xu
parent adc3fcf155
commit ee97dc7db4
1 changed files with 48 additions and 21 deletions
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69
arch/s390/crypto/des_s390.c
View File

@ -25,6 +25,7 @@
#define DES3_KEY_SIZE (3 * DES_KEY_SIZE)
static u8 *ctrblk;
static DEFINE_SPINLOCK(ctrblk_lock);
struct s390_des_ctx {
u8 iv[DES_BLOCK_SIZE];
@ -368,54 +369,80 @@ static struct crypto_alg cbc_des3_alg = {
}
};
static unsigned int __ctrblk_init(u8 *ctrptr, unsigned int nbytes)
{
unsigned int i, n;
/* align to block size, max. PAGE_SIZE */
n = (nbytes > PAGE_SIZE) ? PAGE_SIZE : nbytes & ~(DES_BLOCK_SIZE - 1);
for (i = DES_BLOCK_SIZE; i < n; i += DES_BLOCK_SIZE) {
memcpy(ctrptr + i, ctrptr + i - DES_BLOCK_SIZE, DES_BLOCK_SIZE);
crypto_inc(ctrptr + i, DES_BLOCK_SIZE);
}
return n;
}
static int ctr_desall_crypt(struct blkcipher_desc *desc, long func,
struct s390_des_ctx *ctx, struct blkcipher_walk *walk)
struct s390_des_ctx *ctx,
struct blkcipher_walk *walk)
{
int ret = blkcipher_walk_virt_block(desc, walk, DES_BLOCK_SIZE);
unsigned int i, n, nbytes;
u8 buf[DES_BLOCK_SIZE];
u8 *out, *in;
unsigned int n, nbytes;
u8 buf[DES_BLOCK_SIZE], ctrbuf[DES_BLOCK_SIZE];
u8 *out, *in, *ctrptr = ctrbuf;
memcpy(ctrblk, walk->iv, DES_BLOCK_SIZE);
if (!walk->nbytes)
return ret;
if (spin_trylock(&ctrblk_lock))
ctrptr = ctrblk;
memcpy(ctrptr, walk->iv, DES_BLOCK_SIZE);
while ((nbytes = walk->nbytes) >= DES_BLOCK_SIZE) {
out = walk->dst.virt.addr;
in = walk->src.virt.addr;
while (nbytes >= DES_BLOCK_SIZE) {
/* align to block size, max. PAGE_SIZE */
n = (nbytes > PAGE_SIZE) ? PAGE_SIZE :
nbytes & ~(DES_BLOCK_SIZE - 1);
for (i = DES_BLOCK_SIZE; i < n; i += DES_BLOCK_SIZE) {
memcpy(ctrblk + i, ctrblk + i - DES_BLOCK_SIZE,
DES_BLOCK_SIZE);
crypto_inc(ctrblk + i, DES_BLOCK_SIZE);
}
ret = crypt_s390_kmctr(func, ctx->key, out, in, n, ctrblk);
if (ret < 0 || ret != n)
if (ctrptr == ctrblk)
n = __ctrblk_init(ctrptr, nbytes);
else
n = DES_BLOCK_SIZE;
ret = crypt_s390_kmctr(func, ctx->key, out, in,
n, ctrptr);
if (ret < 0 || ret != n) {
if (ctrptr == ctrblk)
spin_unlock(&ctrblk_lock);
return -EIO;
}
if (n > DES_BLOCK_SIZE)
memcpy(ctrblk, ctrblk + n - DES_BLOCK_SIZE,
memcpy(ctrptr, ctrptr + n - DES_BLOCK_SIZE,
DES_BLOCK_SIZE);
crypto_inc(ctrblk, DES_BLOCK_SIZE);
crypto_inc(ctrptr, DES_BLOCK_SIZE);
out += n;
in += n;
nbytes -= n;
}
ret = blkcipher_walk_done(desc, walk, nbytes);
}
if (ctrptr == ctrblk) {
if (nbytes)
memcpy(ctrbuf, ctrptr, DES_BLOCK_SIZE);
else
memcpy(walk->iv, ctrptr, DES_BLOCK_SIZE);
spin_unlock(&ctrblk_lock);
}
/* final block may be < DES_BLOCK_SIZE, copy only nbytes */
if (nbytes) {
out = walk->dst.virt.addr;
in = walk->src.virt.addr;
ret = crypt_s390_kmctr(func, ctx->key, buf, in,
DES_BLOCK_SIZE, ctrblk);
DES_BLOCK_SIZE, ctrbuf);
if (ret < 0 || ret != DES_BLOCK_SIZE)
return -EIO;
memcpy(out, buf, nbytes);
crypto_inc(ctrblk, DES_BLOCK_SIZE);
crypto_inc(ctrbuf, DES_BLOCK_SIZE);
ret = blkcipher_walk_done(desc, walk, 0);
memcpy(walk->iv, ctrbuf, DES_BLOCK_SIZE);
}
memcpy(walk->iv, ctrblk, DES_BLOCK_SIZE);
return ret;
}