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Commit ee97dc7d authored by Harald Freudenberger's avatar Harald Freudenberger Committed by Herbert Xu
Browse files

crypto: s390 - fix des and des3_ede ctr concurrency issue 



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: default avatarHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent adc3fcf1

arch/s390/crypto/des_s390.c

+48 −21
Original line number Diff line number Diff line
@@ -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;



	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;

}