Commit 6212f2c7 authored by Sebastian Siewior's avatar Sebastian Siewior Committed by Herbert Xu
Browse files

[CRYPTO] xts: Use proper alignment 



The XTS blockmode uses a copy of the IV which is saved on the stack
and may or may not be properly aligned. If it is not, it will break
hardware cipher like the geode or padlock.
This patch encrypts the IV in place so we don't have to worry about
alignment.

Signed-off-by: default avatarSebastian Siewior <sebastian@breakpoint.cc>
Tested-by: default avatarStefan Hellermann <stefan@the2masters.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent bc97f19d

crypto/xts.c

+6 −7
Original line number Diff line number Diff line
@@ -77,16 +77,16 @@ static int setkey(struct crypto_tfm *parent, const u8 *key, 
}



struct sinfo {

	be128 t;

	be128 *t;

	struct crypto_tfm *tfm;

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);

};



static inline void xts_round(struct sinfo *s, void *dst, const void *src)

{

	be128_xor(dst, &s->t, src);		/* PP <- T xor P */

	be128_xor(dst, s->t, src);		/* PP <- T xor P */

	s->fn(s->tfm, dst, dst);		/* CC <- E(Key1,PP) */

	be128_xor(dst, dst, &s->t);		/* C <- T xor CC */

	be128_xor(dst, dst, s->t);		/* C <- T xor CC */

}



static int crypt(struct blkcipher_desc *d,
@@ -101,7 +101,6 @@ static int crypt(struct blkcipher_desc *d, 
		.tfm = crypto_cipher_tfm(ctx->child),

		.fn = fn

	};

	be128 *iv;

	u8 *wsrc;

	u8 *wdst;
@@ -109,20 +108,20 @@ static int crypt(struct blkcipher_desc *d, 
	if (!w->nbytes)

		return err;



	s.t = (be128 *)w->iv;

	avail = w->nbytes;



	wsrc = w->src.virt.addr;

	wdst = w->dst.virt.addr;



	/* calculate first value of T */

	iv = (be128 *)w->iv;

	tw(crypto_cipher_tfm(ctx->tweak), (void *)&s.t, w->iv);

	tw(crypto_cipher_tfm(ctx->tweak), w->iv, w->iv);



	goto first;



	for (;;) {

		do {

			gf128mul_x_ble(&s.t, &s.t);

			gf128mul_x_ble(s.t, s.t);



first:

			xts_round(&s, wdst, wsrc);

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