[PATCH v6 17/18] crypto: ccm: Remove VLA usage
From: Kees Cook <hidden>
Date: 2018-07-24 16:56:22
Also in:
dm-devel, linux-crypto, linux-pm, linux-wireless, lkml, netdev
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
From: Ard Biesheuvel <redacted> 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 <redacted> Signed-off-by: Kees Cook <redacted> --- 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