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crypto: ccm - Remove VLA usage 

In the quest to remove all stack VLA usage from the kernel[1], this drops
AHASH_REQUEST_ON_STACK by preallocating the ahash request area combined
with the skcipher area (which are not used at the same time).

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
hifive-unleashed-5.1
Ard Biesheuvel 2018-08-07 14:18:37 -07:00 committed by Herbert Xu
parent d73d67fbcb
commit ebf533adc8
1 changed files with 6 additions and 3 deletions
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9
crypto/ccm.c
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@ -50,7 +50,10 @@ struct crypto_ccm_req_priv_ctx {
u32 flags;
struct scatterlist src[3];
struct scatterlist dst[3];
struct skcipher_request skreq;
union {
struct ahash_request ahreq;
struct skcipher_request skreq;
};
};
struct cbcmac_tfm_ctx {
@ -181,7 +184,7 @@ static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
AHASH_REQUEST_ON_STACK(ahreq, ctx->mac);
struct ahash_request *ahreq = &pctx->ahreq;
unsigned int assoclen = req->assoclen;
struct scatterlist sg[3];
u8 *odata = pctx->odata;
@ -427,7 +430,7 @@ static int crypto_ccm_init_tfm(struct crypto_aead *tfm)
crypto_aead_set_reqsize(
tfm,
align + sizeof(struct crypto_ccm_req_priv_ctx) +
crypto_skcipher_reqsize(ctr));
max(crypto_ahash_reqsize(mac), crypto_skcipher_reqsize(ctr)));
return 0;