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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id p3-v6sm24884590pfo.130.2018.07.16.21.21.52 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 16 Jul 2018 21:21:53 -0700 (PDT) From: Kees Cook To: Herbert Xu Cc: Kees Cook , Arnd Bergmann , Eric Biggers , "Gustavo A. R. Silva" , Alasdair Kergon , Giovanni Cabiddu , Lars Persson , Mike Snitzer , Rabin Vincent , Tim Chen , linux-crypto@vger.kernel.org, qat-linux@intel.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH v5 01/11] crypto: xcbc: Remove VLA usage Date: Mon, 16 Jul 2018 21:21:40 -0700 Message-Id: <20180717042150.37761-2-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180717042150.37761-1-keescook@chromium.org> References: <20180717042150.37761-1-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 | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/crypto/xcbc.c b/crypto/xcbc.c index 25c75af50d3f..7aa03beed795 100644 --- a/crypto/xcbc.c +++ b/crypto/xcbc.c @@ -57,6 +57,8 @@ 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) { @@ -65,7 +67,10 @@ static int crypto_xcbc_digest_setkey(struct crypto_shash *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]; + + if (WARN_ON(bs > sizeof(key1))) + return -EINVAL; if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen))) return err; @@ -212,7 +217,7 @@ 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