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authorKees Cook <keescook@chromium.org>2018-08-07 14:18:35 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2018-09-04 11:35:03 +0800
commit3bdd23f886c08a0d649c535e1e2cf083ec600036 (patch)
tree80ea091af3f8ed5646cf53a58cb485966c9fff66
parent578bdaabd015b9b164842c3e8ace9802f38e7ecc (diff)
crypto: xcbc - Remove VLA usage
In the quest to remove all stack VLA usage from the kernel[1], this uses the maximum blocksize and adds a sanity check. For xcbc, the blocksize must always be 16, so use that, since it's already being enforced during instantiation. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/xcbc.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/crypto/xcbc.c b/crypto/xcbc.c
index 25c75af50d3f..c055f57fab11 100644
--- a/crypto/xcbc.c
+++ b/crypto/xcbc.c
@@ -57,15 +57,17 @@ struct xcbc_desc_ctx {
u8 ctx[];
};
+#define XCBC_BLOCKSIZE 16
+
static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
const u8 *inkey, unsigned int keylen)
{
unsigned long alignmask = crypto_shash_alignmask(parent);
struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
- int bs = crypto_shash_blocksize(parent);
u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
int err = 0;
- u8 key1[bs];
+ u8 key1[XCBC_BLOCKSIZE];
+ int bs = sizeof(key1);
if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
return err;
@@ -212,7 +214,7 @@ static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
return PTR_ERR(alg);
switch(alg->cra_blocksize) {
- case 16:
+ case XCBC_BLOCKSIZE:
break;
default:
goto out_put_alg;