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Commit 80da44c2 authored by Marcelo Cerri's avatar Marcelo Cerri Committed by Herbert Xu
Browse files

crypto: vmx - Fix memory corruption caused by p8_ghash 



This patch changes the p8_ghash driver to use ghash-generic as a fixed
fallback implementation. This allows the correct value of descsize to be
defined directly in its shash_alg structure and avoids problems with
incorrect buffer sizes when its state is exported or imported.

Reported-by: default avatarJan Stancek <jstancek@redhat.com>
Fixes: cc333cd6 ("crypto: vmx - Adding GHASH routines for VMX module")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMarcelo Cerri <marcelo.cerri@canonical.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent a397ba82

drivers/crypto/vmx/ghash.c

+16 −15
Original line number Diff line number Diff line
@@ -26,16 +26,13 @@ 
#include <linux/hardirq.h>

#include <asm/switch_to.h>

#include <crypto/aes.h>

#include <crypto/ghash.h>

#include <crypto/scatterwalk.h>

#include <crypto/internal/hash.h>

#include <crypto/b128ops.h>



#define IN_INTERRUPT in_interrupt()



#define GHASH_BLOCK_SIZE (16)

#define GHASH_DIGEST_SIZE (16)

#define GHASH_KEY_LEN (16)



void gcm_init_p8(u128 htable[16], const u64 Xi[2]);

void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);

void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
@@ -55,16 +52,11 @@ struct p8_ghash_desc_ctx { 


static int p8_ghash_init_tfm(struct crypto_tfm *tfm)

{

	const char *alg;

	const char *alg = "ghash-generic";

	struct crypto_shash *fallback;

	struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);

	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);



	if (!(alg = crypto_tfm_alg_name(tfm))) {

		printk(KERN_ERR "Failed to get algorithm name.\n");

		return -ENOENT;

	}



	fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);

	if (IS_ERR(fallback)) {

		printk(KERN_ERR
@@ -78,10 +70,18 @@ static int p8_ghash_init_tfm(struct crypto_tfm *tfm) 
	crypto_shash_set_flags(fallback,

			       crypto_shash_get_flags((struct crypto_shash

						       *) tfm));

	ctx->fallback = fallback;



	shash_tfm->descsize = sizeof(struct p8_ghash_desc_ctx)

	    + crypto_shash_descsize(fallback);

	/* Check if the descsize defined in the algorithm is still enough. */

	if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx)

	    + crypto_shash_descsize(fallback)) {

		printk(KERN_ERR

		       "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n",

		       alg,

		       shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx),

		       crypto_shash_descsize(fallback));

		return -EINVAL;

	}

	ctx->fallback = fallback;



	return 0;

}
@@ -113,7 +113,7 @@ static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key, 
{

	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));



	if (keylen != GHASH_KEY_LEN)

	if (keylen != GHASH_BLOCK_SIZE)

		return -EINVAL;



	preempt_disable();
@@ -211,7 +211,8 @@ struct shash_alg p8_ghash_alg = { 
	.update = p8_ghash_update,

	.final = p8_ghash_final,

	.setkey = p8_ghash_setkey,

	.descsize = sizeof(struct p8_ghash_desc_ctx),

	.descsize = sizeof(struct p8_ghash_desc_ctx)

		+ sizeof(struct ghash_desc_ctx),

	.base = {

		 .cra_name = "ghash",

		 .cra_driver_name = "p8_ghash",