From: David Howells Subject: [PATCH 08/16] MPILIB: Reinstate mpi_cmp[_ui]() and export for RSA signature verification Date: Fri, 14 Sep 2012 00:49:15 +0100 Message-ID: <20120913234915.3575.50626.stgit@warthog.procyon.org.uk> References: <20120913234802.3575.77103.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-crypto@vger.kernel.org, zohar@us.ibm.com, dmitry.kasatkin@intel.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org To: herbert@gondor.hengli.com.au, rusty@rustcorp.com.au Return-path: In-Reply-To: <20120913234802.3575.77103.stgit@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Reinstate and export mpi_cmp() and mpi_cmp_ui() from the MPI library for use by RSA signature verification as per RFC3447 section 5.2.2 step 1. Signed-off-by: David Howells --- lib/mpi/Makefile | 1 + lib/mpi/mpi-cmp.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+) create mode 100644 lib/mpi/mpi-cmp.c diff --git a/lib/mpi/Makefile b/lib/mpi/Makefile index 45ca90a..019a68c 100644 --- a/lib/mpi/Makefile +++ b/lib/mpi/Makefile @@ -14,6 +14,7 @@ mpi-y = \ generic_mpih-add1.o \ mpicoder.o \ mpi-bit.o \ + mpi-cmp.o \ mpih-cmp.o \ mpih-div.o \ mpih-mul.o \ diff --git a/lib/mpi/mpi-cmp.c b/lib/mpi/mpi-cmp.c new file mode 100644 index 0000000..1871e7b --- /dev/null +++ b/lib/mpi/mpi-cmp.c @@ -0,0 +1,70 @@ +/* mpi-cmp.c - MPI functions + * Copyright (C) 1998, 1999 Free Software Foundation, Inc. + * + * This file is part of GnuPG. + * + * GnuPG is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * GnuPG is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include "mpi-internal.h" + +int mpi_cmp_ui(MPI u, unsigned long v) +{ + mpi_limb_t limb = v; + + mpi_normalize(u); + if (!u->nlimbs && !limb) + return 0; + if (u->sign) + return -1; + if (u->nlimbs > 1) + return 1; + + if (u->d[0] == limb) + return 0; + else if (u->d[0] > limb) + return 1; + else + return -1; +} +EXPORT_SYMBOL_GPL(mpi_cmp_ui); + +int mpi_cmp(MPI u, MPI v) +{ + mpi_size_t usize, vsize; + int cmp; + + mpi_normalize(u); + mpi_normalize(v); + usize = u->nlimbs; + vsize = v->nlimbs; + if (!u->sign && v->sign) + return 1; + if (u->sign && !v->sign) + return -1; + if (usize != vsize && !u->sign && !v->sign) + return usize - vsize; + if (usize != vsize && u->sign && v->sign) + return vsize + usize; + if (!usize) + return 0; + cmp = mpihelp_cmp(u->d, v->d, usize); + if (!cmp) + return 0; + if ((cmp < 0 ? 1 : 0) == (u->sign ? 1 : 0)) + return 1; + return -1; +} +EXPORT_SYMBOL_GPL(mpi_cmp);