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-rw-r--r--lib/mpi/mpi-pow.c314
1 files changed, 0 insertions, 314 deletions
diff --git a/lib/mpi/mpi-pow.c b/lib/mpi/mpi-pow.c
deleted file mode 100644
index 2fd7a46d55ec..000000000000
--- a/lib/mpi/mpi-pow.c
+++ /dev/null
@@ -1,314 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* mpi-pow.c - MPI functions
- * Copyright (C) 1994, 1996, 1998, 2000 Free Software Foundation, Inc.
- *
- * This file is part of GnuPG.
- *
- * Note: This code is heavily based on the GNU MP Library.
- * Actually it's the same code with only minor changes in the
- * way the data is stored; this is to support the abstraction
- * of an optional secure memory allocation which may be used
- * to avoid revealing of sensitive data due to paging etc.
- * The GNU MP Library itself is published under the LGPL;
- * however I decided to publish this code under the plain GPL.
- */
-
-#include <linux/sched.h>
-#include <linux/string.h>
-#include "mpi-internal.h"
-#include "longlong.h"
-
-/****************
- * RES = BASE ^ EXP mod MOD
- */
-int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
-{
- mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL;
- struct karatsuba_ctx karactx = {};
- mpi_ptr_t xp_marker = NULL;
- mpi_ptr_t tspace = NULL;
- mpi_ptr_t rp, ep, mp, bp;
- mpi_size_t esize, msize, bsize, rsize;
- int msign, bsign, rsign;
- mpi_size_t size;
- int mod_shift_cnt;
- int negative_result;
- int assign_rp = 0;
- mpi_size_t tsize = 0; /* to avoid compiler warning */
- /* fixme: we should check that the warning is void */
- int rc = -ENOMEM;
-
- esize = exp->nlimbs;
- msize = mod->nlimbs;
- size = 2 * msize;
- msign = mod->sign;
-
- rp = res->d;
- ep = exp->d;
-
- if (!msize)
- return -EINVAL;
-
- if (!esize) {
- /* Exponent is zero, result is 1 mod MOD, i.e., 1 or 0
- * depending on if MOD equals 1. */
- res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1;
- if (res->nlimbs) {
- if (mpi_resize(res, 1) < 0)
- goto enomem;
- rp = res->d;
- rp[0] = 1;
- }
- res->sign = 0;
- goto leave;
- }
-
- /* Normalize MOD (i.e. make its most significant bit set) as required by
- * mpn_divrem. This will make the intermediate values in the calculation
- * slightly larger, but the correct result is obtained after a final
- * reduction using the original MOD value. */
- mp = mp_marker = mpi_alloc_limb_space(msize);
- if (!mp)
- goto enomem;
- mod_shift_cnt = count_leading_zeros(mod->d[msize - 1]);
- if (mod_shift_cnt)
- mpihelp_lshift(mp, mod->d, msize, mod_shift_cnt);
- else
- MPN_COPY(mp, mod->d, msize);
-
- bsize = base->nlimbs;
- bsign = base->sign;
- if (bsize > msize) { /* The base is larger than the module. Reduce it. */
- /* Allocate (BSIZE + 1) with space for remainder and quotient.
- * (The quotient is (bsize - msize + 1) limbs.) */
- bp = bp_marker = mpi_alloc_limb_space(bsize + 1);
- if (!bp)
- goto enomem;
- MPN_COPY(bp, base->d, bsize);
- /* We don't care about the quotient, store it above the remainder,
- * at BP + MSIZE. */
- mpihelp_divrem(bp + msize, 0, bp, bsize, mp, msize);
- bsize = msize;
- /* Canonicalize the base, since we are going to multiply with it
- * quite a few times. */
- MPN_NORMALIZE(bp, bsize);
- } else
- bp = base->d;
-
- if (!bsize) {
- res->nlimbs = 0;
- res->sign = 0;
- goto leave;
- }
-
- if (res->alloced < size) {
- /* We have to allocate more space for RES. If any of the input
- * parameters are identical to RES, defer deallocation of the old
- * space. */
- if (rp == ep || rp == mp || rp == bp) {
- rp = mpi_alloc_limb_space(size);
- if (!rp)
- goto enomem;
- assign_rp = 1;
- } else {
- if (mpi_resize(res, size) < 0)
- goto enomem;
- rp = res->d;
- }
- } else { /* Make BASE, EXP and MOD not overlap with RES. */
- if (rp == bp) {
- /* RES and BASE are identical. Allocate temp. space for BASE. */
- BUG_ON(bp_marker);
- bp = bp_marker = mpi_alloc_limb_space(bsize);
- if (!bp)
- goto enomem;
- MPN_COPY(bp, rp, bsize);
- }
- if (rp == ep) {
- /* RES and EXP are identical. Allocate temp. space for EXP. */
- ep = ep_marker = mpi_alloc_limb_space(esize);
- if (!ep)
- goto enomem;
- MPN_COPY(ep, rp, esize);
- }
- if (rp == mp) {
- /* RES and MOD are identical. Allocate temporary space for MOD. */
- BUG_ON(mp_marker);
- mp = mp_marker = mpi_alloc_limb_space(msize);
- if (!mp)
- goto enomem;
- MPN_COPY(mp, rp, msize);
- }
- }
-
- MPN_COPY(rp, bp, bsize);
- rsize = bsize;
- rsign = bsign;
-
- {
- mpi_size_t i;
- mpi_ptr_t xp;
- int c;
- mpi_limb_t e;
- mpi_limb_t carry_limb;
-
- xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1));
- if (!xp)
- goto enomem;
-
- negative_result = (ep[0] & 1) && base->sign;
-
- i = esize - 1;
- e = ep[i];
- c = count_leading_zeros(e);
- e = (e << c) << 1; /* shift the exp bits to the left, lose msb */
- c = BITS_PER_MPI_LIMB - 1 - c;
-
- /* Main loop.
- *
- * Make the result be pointed to alternately by XP and RP. This
- * helps us avoid block copying, which would otherwise be necessary
- * with the overlap restrictions of mpihelp_divmod. With 50% probability
- * the result after this loop will be in the area originally pointed
- * by RP (==RES->d), and with 50% probability in the area originally
- * pointed to by XP.
- */
-
- for (;;) {
- while (c) {
- mpi_ptr_t tp;
- mpi_size_t xsize;
-
- /*if (mpihelp_mul_n(xp, rp, rp, rsize) < 0) goto enomem */
- if (rsize < KARATSUBA_THRESHOLD)
- mpih_sqr_n_basecase(xp, rp, rsize);
- else {
- if (!tspace) {
- tsize = 2 * rsize;
- tspace =
- mpi_alloc_limb_space(tsize);
- if (!tspace)
- goto enomem;
- } else if (tsize < (2 * rsize)) {
- mpi_free_limb_space(tspace);
- tsize = 2 * rsize;
- tspace =
- mpi_alloc_limb_space(tsize);
- if (!tspace)
- goto enomem;
- }
- mpih_sqr_n(xp, rp, rsize, tspace);
- }
-
- xsize = 2 * rsize;
- if (xsize > msize) {
- mpihelp_divrem(xp + msize, 0, xp, xsize,
- mp, msize);
- xsize = msize;
- }
-
- tp = rp;
- rp = xp;
- xp = tp;
- rsize = xsize;
-
- if ((mpi_limb_signed_t) e < 0) {
- /*mpihelp_mul( xp, rp, rsize, bp, bsize ); */
- if (bsize < KARATSUBA_THRESHOLD) {
- mpi_limb_t tmp;
- if (mpihelp_mul
- (xp, rp, rsize, bp, bsize,
- &tmp) < 0)
- goto enomem;
- } else {
- if (mpihelp_mul_karatsuba_case
- (xp, rp, rsize, bp, bsize,
- &karactx) < 0)
- goto enomem;
- }
-
- xsize = rsize + bsize;
- if (xsize > msize) {
- mpihelp_divrem(xp + msize, 0,
- xp, xsize, mp,
- msize);
- xsize = msize;
- }
-
- tp = rp;
- rp = xp;
- xp = tp;
- rsize = xsize;
- }
- e <<= 1;
- c--;
- cond_resched();
- }
-
- i--;
- if (i < 0)
- break;
- e = ep[i];
- c = BITS_PER_MPI_LIMB;
- }
-
- /* We shifted MOD, the modulo reduction argument, left MOD_SHIFT_CNT
- * steps. Adjust the result by reducing it with the original MOD.
- *
- * Also make sure the result is put in RES->d (where it already
- * might be, see above).
- */
- if (mod_shift_cnt) {
- carry_limb =
- mpihelp_lshift(res->d, rp, rsize, mod_shift_cnt);
- rp = res->d;
- if (carry_limb) {
- rp[rsize] = carry_limb;
- rsize++;
- }
- } else {
- MPN_COPY(res->d, rp, rsize);
- rp = res->d;
- }
-
- if (rsize >= msize) {
- mpihelp_divrem(rp + msize, 0, rp, rsize, mp, msize);
- rsize = msize;
- }
-
- /* Remove any leading zero words from the result. */
- if (mod_shift_cnt)
- mpihelp_rshift(rp, rp, rsize, mod_shift_cnt);
- MPN_NORMALIZE(rp, rsize);
- }
-
- if (negative_result && rsize) {
- if (mod_shift_cnt)
- mpihelp_rshift(mp, mp, msize, mod_shift_cnt);
- mpihelp_sub(rp, mp, msize, rp, rsize);
- rsize = msize;
- rsign = msign;
- MPN_NORMALIZE(rp, rsize);
- }
- res->nlimbs = rsize;
- res->sign = rsign;
-
-leave:
- rc = 0;
-enomem:
- mpihelp_release_karatsuba_ctx(&karactx);
- if (assign_rp)
- mpi_assign_limb_space(res, rp, size);
- if (mp_marker)
- mpi_free_limb_space(mp_marker);
- if (bp_marker)
- mpi_free_limb_space(bp_marker);
- if (ep_marker)
- mpi_free_limb_space(ep_marker);
- if (xp_marker)
- mpi_free_limb_space(xp_marker);
- if (tspace)
- mpi_free_limb_space(tspace);
- return rc;
-}
-EXPORT_SYMBOL_GPL(mpi_powm);
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