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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id r7-v6sm7956591pfd.154.2018.06.28.17.28.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 28 Jun 2018 17:28:48 -0700 (PDT) From: Kees Cook To: Herbert Xu Date: Thu, 28 Jun 2018 17:28:36 -0700 Message-Id: <20180629002843.31095-3-keescook@chromium.org> In-Reply-To: <20180629002843.31095-1-keescook@chromium.org> References: <20180629002843.31095-1-keescook@chromium.org> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Fri, 29 Jun 2018 00:28:52 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Fri, 29 Jun 2018 00:28:52 +0000 (UTC) for IP:'209.85.192.194' DOMAIN:'mail-pf0-f194.google.com' HELO:'mail-pf0-f194.google.com' FROM:'keescook@chromium.org' RCPT:'' X-RedHat-Spam-Score: -0.112 (DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_PASS) 209.85.192.194 mail-pf0-f194.google.com 209.85.192.194 mail-pf0-f194.google.com X-Scanned-By: MIMEDefang 2.84 on 10.5.110.49 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-loop: dm-devel@redhat.com Cc: Giovanni Cabiddu , Kees Cook , Arnd Bergmann , Eric Biggers , Mike Snitzer , "Gustavo A. R. Silva" , qat-linux@intel.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com, linux-crypto@vger.kernel.org, Lars Persson , Tim Chen , "David S. Miller" , Alasdair Kergon , Rabin Vincent Subject: [dm-devel] [PATCH v3 2/9] crypto: cbc: 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 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Fri, 29 Jun 2018 00:29:56 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP In the quest to remove all stack VLA usage from the kernel[1], this uses the upper bounds on blocksize. Since this is always a cipher blocksize, use the existing cipher max blocksize. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook --- include/crypto/cbc.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/crypto/cbc.h b/include/crypto/cbc.h index f5b8bfc22e6d..47db0aac2ab9 100644 --- a/include/crypto/cbc.h +++ b/include/crypto/cbc.h @@ -113,7 +113,9 @@ static inline int crypto_cbc_decrypt_inplace( unsigned int bsize = crypto_skcipher_blocksize(tfm); unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; - u8 last_iv[bsize]; + u8 last_iv[MAX_CIPHER_BLOCKSIZE]; + + BUG_ON(bsize > sizeof(last_iv)); /* Start of the last block. */ src += nbytes - (nbytes & (bsize - 1)) - bsize;