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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id o3-v6sm2262323pgp.3.2018.08.07.14.18.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 07 Aug 2018 14:18:46 -0700 (PDT) From: Kees Cook To: Herbert Xu Date: Tue, 7 Aug 2018 14:18:35 -0700 Message-Id: <20180807211843.47586-2-keescook@chromium.org> In-Reply-To: <20180807211843.47586-1-keescook@chromium.org> References: <20180807211843.47586-1-keescook@chromium.org> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Tue, 07 Aug 2018 21:18:50 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Tue, 07 Aug 2018 21:18:50 +0000 (UTC) for IP:'209.85.215.193' DOMAIN:'mail-pg1-f193.google.com' HELO:'mail-pg1-f193.google.com' FROM:'keescook@chromium.org' RCPT:'' X-RedHat-Spam-Score: -0.131 (DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_PASS) 209.85.215.193 mail-pg1-f193.google.com 209.85.215.193 mail-pg1-f193.google.com X-Scanned-By: MIMEDefang 2.84 on 10.5.110.44 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-loop: dm-devel@redhat.com Cc: Giovanni Cabiddu , Matthew Wilcox , linux-kernel@vger.kernel.org, Kees Cook , Mike Snitzer , Ard Biesheuvel , Rasmus Villemoes , Eric Biggers , Will Deacon , qat-linux@intel.com, Arnd Bergmann , "David S. Miller" , "Gustavo A. R. Silva" , dm-devel@redhat.com, Geert Uytterhoeven , David Woodhouse , Tudor-Dan Ambarus , Andrew Morton , Thomas Gleixner , Alasdair Kergon , linux-crypto@vger.kernel.org Subject: [dm-devel] [PATCH v8 1/9] crypto: xcbc: Remove VLA usage X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 07 Aug 2018 21:20:46 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP 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;