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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id 5-v6sm4465319pgc.86.2018.08.02.15.51.55 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 02 Aug 2018 15:51:56 -0700 (PDT) From: Kees Cook To: Herbert Xu Cc: Kees Cook , Ard Biesheuvel , Giovanni Cabiddu , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Tudor-Dan Ambarus , Andrew Morton , Thomas Gleixner , Geert Uytterhoeven , Arnd Bergmann , Will Deacon , Rasmus Villemoes , David Woodhouse , Matthew Wilcox , "David S. Miller" , linux-crypto@vger.kernel.org, qat-linux@intel.com, linux-kernel@vger.kernel.org Subject: [PATCH v7 1/9] crypto: xcbc: Remove VLA usage Date: Thu, 2 Aug 2018 15:51:44 -0700 Message-Id: <20180802225152.19194-2-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180802225152.19194-1-keescook@chromium.org> References: <20180802225152.19194-1-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the quest to remove all stack VLA usage from the kernel[1], this uses the maximum blocksize and adds a sanity check. For xcbc, the blocksize must always be 16, so use that, since it's already being enforced during instantiation. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook --- crypto/xcbc.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/crypto/xcbc.c b/crypto/xcbc.c index 25c75af50d3f..c055f57fab11 100644 --- a/crypto/xcbc.c +++ b/crypto/xcbc.c @@ -57,15 +57,17 @@ struct xcbc_desc_ctx { u8 ctx[]; }; +#define XCBC_BLOCKSIZE 16 + static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, const u8 *inkey, unsigned int keylen) { unsigned long alignmask = crypto_shash_alignmask(parent); struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent); - int bs = crypto_shash_blocksize(parent); u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); int err = 0; - u8 key1[bs]; + u8 key1[XCBC_BLOCKSIZE]; + int bs = sizeof(key1); if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen))) return err; @@ -212,7 +214,7 @@ static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) return PTR_ERR(alg); switch(alg->cra_blocksize) { - case 16: + case XCBC_BLOCKSIZE: break; default: goto out_put_alg; -- 2.17.1