From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Date: Tue, 24 Jul 2018 16:49:35 +0000 Subject: [PATCH v6 17/18] crypto: ccm: Remove VLA usage Message-Id: <20180724164936.37477-18-keescook@chromium.org> List-Id: References: <20180724164936.37477-1-keescook@chromium.org> In-Reply-To: <20180724164936.37477-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Herbert Xu Cc: Kees Cook , Ard Biesheuvel , Arnd Bergmann , Eric Biggers , "Gustavo A. R. Silva" , Alasdair Kergon , Rabin Vincent , Tim Chen , "Rafael J. Wysocki" , Pavel Machek , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Philipp Reisner , Lars Ellenberg , Jens Axboe , Giovanni Cabiddu , Mike Snitzer , Paul Mackerras , Greg Kroah-Hartman , David Howells , Johannes Berg , Tudor-Dan Ambarus , Jia-Ju Bai , Andrew Morton , Geert Uytterhoeven , Josh Poimboeuf , David Woodhouse , Will Deacon , dm-devel@redhat.com, linux-pm@vger.kernel.org, linux-crypto@vger.kernel.org, drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, qat-linux@intel.com, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, devel@driverdev.osuosl.org, linux-afs@lists.infradead.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org From: Ard Biesheuvel In the quest to remove all stack VLA usage from the kernel[1], this drops AHASH_REQUEST_ON_STACK by preallocated the ahash request area 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 Signed-off-by: Kees Cook --- 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