3.2.56-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>
commit ee97dc7db4cbda33e4241c2d85b42d1835bc8a35 upstream.
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.
Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/s390/crypto/des_s390.c | 69 +++++++++++++++++++++++++++++++--------------
1 file changed, 48 insertions(+), 21 deletions(-)
--- a/arch/s390/crypto/des_s390.c
+++ b/arch/s390/crypto/des_s390.c
@@ -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];
@@ -376,54 +377,80 @@ 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;
+
+ if (!walk->nbytes)
+ return ret;
- memcpy(ctrblk, walk->iv, DES_BLOCK_SIZE);
+ 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;
}
--
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