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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-10 21:51:23 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-10 21:51:23 -0800 |
commit | e7691a1ce341c80ed9504244a36b31c025217391 (patch) | |
tree | e9941bb350f64a726130e299c411821da6f41a53 /lib/mpi/mpi-mpow.c | |
parent | 5cd9599bba428762025db6027764f1c59d0b1e1b (diff) | |
parent | 8fcc99549522fc7a0bbaeb5755855ab0d9a59ce8 (diff) | |
download | linux-e7691a1ce341c80ed9504244a36b31c025217391.tar.bz2 |
Merge branch 'for-linus' of git://selinuxproject.org/~jmorris/linux-security
* 'for-linus' of git://selinuxproject.org/~jmorris/linux-security: (32 commits)
ima: fix invalid memory reference
ima: free duplicate measurement memory
security: update security_file_mmap() docs
selinux: Casting (void *) value returned by kmalloc is useless
apparmor: fix module parameter handling
Security: tomoyo: add .gitignore file
tomoyo: add missing rcu_dereference()
apparmor: add missing rcu_dereference()
evm: prevent racing during tfm allocation
evm: key must be set once during initialization
mpi/mpi-mpow: NULL dereference on allocation failure
digsig: build dependency fix
KEYS: Give key types their own lockdep class for key->sem
TPM: fix transmit_cmd error logic
TPM: NSC and TIS drivers X86 dependency fix
TPM: Export wait_for_stat for other vendor specific drivers
TPM: Use vendor specific function for status probe
tpm_tis: add delay after aborting command
tpm_tis: Check return code from getting timeouts/durations
tpm: Introduce function to poll for result of self test
...
Fix up trivial conflict in lib/Makefile due to addition of CONFIG_MPI
and SIGSIG next to CONFIG_DQL addition.
Diffstat (limited to 'lib/mpi/mpi-mpow.c')
-rw-r--r-- | lib/mpi/mpi-mpow.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/lib/mpi/mpi-mpow.c b/lib/mpi/mpi-mpow.c new file mode 100644 index 000000000000..7328d0d6c748 --- /dev/null +++ b/lib/mpi/mpi-mpow.c @@ -0,0 +1,134 @@ +/* mpi-mpow.c - MPI functions + * Copyright (C) 1998, 1999, 2000 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" +#include "longlong.h" + +static int build_index(const MPI *exparray, int k, int i, int t) +{ + int j, bitno; + int index = 0; + + bitno = t - i; + for (j = k - 1; j >= 0; j--) { + index <<= 1; + if (mpi_test_bit(exparray[j], bitno)) + index |= 1; + } + return index; +} + +/**************** + * RES = (BASE[0] ^ EXP[0]) * (BASE[1] ^ EXP[1]) * ... * mod M + */ +int mpi_mulpowm(MPI res, MPI *basearray, MPI *exparray, MPI m) +{ + int rc = -ENOMEM; + int k; /* number of elements */ + int t; /* bit size of largest exponent */ + int i, j, idx; + MPI *G = NULL; /* table with precomputed values of size 2^k */ + MPI tmp = NULL; + + for (k = 0; basearray[k]; k++) + ; + if (!k) { + pr_emerg("mpi_mulpowm: assert(k) failed\n"); + BUG(); + } + for (t = 0, i = 0; (tmp = exparray[i]); i++) { + j = mpi_get_nbits(tmp); + if (j > t) + t = j; + } + if (i != k) { + pr_emerg("mpi_mulpowm: assert(i==k) failed\n"); + BUG(); + } + if (!t) { + pr_emerg("mpi_mulpowm: assert(t) failed\n"); + BUG(); + } + if (k >= 10) { + pr_emerg("mpi_mulpowm: assert(k<10) failed\n"); + BUG(); + } + + G = kzalloc((1 << k) * sizeof *G, GFP_KERNEL); + if (!G) + goto err_out; + + /* and calculate */ + tmp = mpi_alloc(mpi_get_nlimbs(m) + 1); + if (!tmp) + goto nomem; + if (mpi_set_ui(res, 1) < 0) + goto nomem; + for (i = 1; i <= t; i++) { + if (mpi_mulm(tmp, res, res, m) < 0) + goto nomem; + idx = build_index(exparray, k, i, t); + if (!(idx >= 0 && idx < (1 << k))) { + pr_emerg("mpi_mulpowm: assert(idx >= 0 && idx < (1<<k)) failed\n"); + BUG(); + } + if (!G[idx]) { + if (!idx) { + G[0] = mpi_alloc_set_ui(1); + if (!G[0]) + goto nomem; + } else { + for (j = 0; j < k; j++) { + if ((idx & (1 << j))) { + if (!G[idx]) { + if (mpi_copy + (&G[idx], + basearray[j]) < 0) + goto nomem; + } else { + if (mpi_mulm + (G[idx], G[idx], + basearray[j], + m) < 0) + goto nomem; + } + } + } + if (!G[idx]) { + G[idx] = mpi_alloc(0); + if (!G[idx]) + goto nomem; + } + } + } + if (mpi_mulm(res, tmp, G[idx], m) < 0) + goto nomem; + } + + rc = 0; +nomem: + /* cleanup */ + mpi_free(tmp); + for (i = 0; i < (1 << k); i++) + mpi_free(G[i]); + kfree(G); +err_out: + return rc; +} |