From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> 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@xxxxxxxxxxxxxx Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- crypto/ccm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/crypto/ccm.c b/crypto/ccm.c index 0a083342ec8c..b242fd0d3262 100644 --- a/crypto/ccm.c +++ b/crypto/ccm.c @@ -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; -- 2.17.1
