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crypto: mxs-dcp - Remove VLA usage of skcipher 

In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.

[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>
This commit is contained in:
Kees Cook 2018-09-18 19:10:57 -07:00 committed by Herbert Xu
parent 28874f2637
commit f805f59d1e
1 changed files with 10 additions and 11 deletions
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21
drivers/crypto/mxs-dcp.c
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@ -84,7 +84,7 @@ struct dcp_async_ctx {
unsigned int hot:1; unsigned int hot:1;
/* Crypto-specific context */ /* Crypto-specific context */
struct crypto_skcipher *fallback; struct crypto_sync_skcipher *fallback;
unsigned int key_len; unsigned int key_len;
uint8_t key[AES_KEYSIZE_128]; uint8_t key[AES_KEYSIZE_128];
}; };
@ -376,10 +376,10 @@ static int mxs_dcp_block_fallback(struct ablkcipher_request *req, int enc)
{ {
struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req); struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
struct dcp_async_ctx *ctx = crypto_ablkcipher_ctx(tfm); struct dcp_async_ctx *ctx = crypto_ablkcipher_ctx(tfm);
SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback); SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback);
int ret; int ret;
skcipher_request_set_tfm(subreq, ctx->fallback); skcipher_request_set_sync_tfm(subreq, ctx->fallback);
skcipher_request_set_callback(subreq, req->base.flags, NULL, NULL); skcipher_request_set_callback(subreq, req->base.flags, NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst, skcipher_request_set_crypt(subreq, req->src, req->dst,
req->nbytes, req->info); req->nbytes, req->info);
@ -460,16 +460,16 @@ static int mxs_dcp_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
* but is supported by in-kernel software implementation, we use * but is supported by in-kernel software implementation, we use
* software fallback. * software fallback.
*/ */
crypto_skcipher_clear_flags(actx->fallback, CRYPTO_TFM_REQ_MASK); crypto_sync_skcipher_clear_flags(actx->fallback, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(actx->fallback, crypto_sync_skcipher_set_flags(actx->fallback,
tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK); tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);
ret = crypto_skcipher_setkey(actx->fallback, key, len); ret = crypto_sync_skcipher_setkey(actx->fallback, key, len);
if (!ret) if (!ret)
return 0; return 0;
tfm->base.crt_flags &= ~CRYPTO_TFM_RES_MASK; tfm->base.crt_flags &= ~CRYPTO_TFM_RES_MASK;
tfm->base.crt_flags |= crypto_skcipher_get_flags(actx->fallback) & tfm->base.crt_flags |= crypto_sync_skcipher_get_flags(actx->fallback) &
CRYPTO_TFM_RES_MASK; CRYPTO_TFM_RES_MASK;
return ret; return ret;
@ -478,11 +478,10 @@ static int mxs_dcp_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
static int mxs_dcp_aes_fallback_init(struct crypto_tfm *tfm) static int mxs_dcp_aes_fallback_init(struct crypto_tfm *tfm)
{ {
const char *name = crypto_tfm_alg_name(tfm); const char *name = crypto_tfm_alg_name(tfm);
const uint32_t flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK;
struct dcp_async_ctx *actx = crypto_tfm_ctx(tfm); struct dcp_async_ctx *actx = crypto_tfm_ctx(tfm);
struct crypto_skcipher *blk; struct crypto_sync_skcipher *blk;
blk = crypto_alloc_skcipher(name, 0, flags); blk = crypto_alloc_sync_skcipher(name, 0, CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(blk)) if (IS_ERR(blk))
return PTR_ERR(blk); return PTR_ERR(blk);
@ -495,7 +494,7 @@ static void mxs_dcp_aes_fallback_exit(struct crypto_tfm *tfm)
{ {
struct dcp_async_ctx *actx = crypto_tfm_ctx(tfm); struct dcp_async_ctx *actx = crypto_tfm_ctx(tfm);
crypto_free_skcipher(actx->fallback); crypto_free_sync_skcipher(actx->fallback);
} }
/* /*