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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2024-07-15 14:03:44 -0700 | 
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2024-07-15 14:03:44 -0700 | 
| commit | a23e1966932464e1c5226cb9ac4ce1d5fc10ba22 (patch) | |
| tree | bf5f1b57faa01ca31656bfc48c7d6b6f0bc39189 /lib/crypto/mpi/mpiutil.c | |
| parent | 7c7b1be19b228b450c2945ec379d7fc6bfef9852 (diff) | |
| parent | f3efefb6fdcce604413135bd8d4c5568e53a1f13 (diff) | |
Merge branch 'next' into for-linus
Prepare input updates for 6.11 merge window.
Diffstat (limited to 'lib/crypto/mpi/mpiutil.c')
| -rw-r--r-- | lib/crypto/mpi/mpiutil.c | 330 | 
1 files changed, 330 insertions, 0 deletions
diff --git a/lib/crypto/mpi/mpiutil.c b/lib/crypto/mpi/mpiutil.c new file mode 100644 index 000000000000..aa8c46544af8 --- /dev/null +++ b/lib/crypto/mpi/mpiutil.c @@ -0,0 +1,330 @@ +/* mpiutil.ac  -  Utility functions for MPI + * 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" + +/* Constants allocated right away at startup.  */ +static MPI constants[MPI_NUMBER_OF_CONSTANTS]; + +/* Initialize the MPI subsystem.  This is called early and allows to + * do some initialization without taking care of threading issues. + */ +static int __init mpi_init(void) +{ +	int idx; +	unsigned long value; + +	for (idx = 0; idx < MPI_NUMBER_OF_CONSTANTS; idx++) { +		switch (idx) { +		case MPI_C_ZERO: +			value = 0; +			break; +		case MPI_C_ONE: +			value = 1; +			break; +		case MPI_C_TWO: +			value = 2; +			break; +		case MPI_C_THREE: +			value = 3; +			break; +		case MPI_C_FOUR: +			value = 4; +			break; +		case MPI_C_EIGHT: +			value = 8; +			break; +		default: +			pr_err("MPI: invalid mpi_const selector %d\n", idx); +			return -EFAULT; +		} +		constants[idx] = mpi_alloc_set_ui(value); +		constants[idx]->flags = (16|32); +	} + +	return 0; +} +postcore_initcall(mpi_init); + +/* Return a constant MPI descripbed by NO which is one of the + * MPI_C_xxx macros.  There is no need to copy this returned value; it + * may be used directly. + */ +MPI mpi_const(enum gcry_mpi_constants no) +{ +	if ((int)no < 0 || no > MPI_NUMBER_OF_CONSTANTS) +		pr_err("MPI: invalid mpi_const selector %d\n", no); +	if (!constants[no]) +		pr_err("MPI: MPI subsystem not initialized\n"); +	return constants[no]; +} +EXPORT_SYMBOL_GPL(mpi_const); + +/**************** + * Note:  It was a bad idea to use the number of limbs to allocate + *	  because on a alpha the limbs are large but we normally need + *	  integers of n bits - So we should change this to bits (or bytes). + * + *	  But mpi_alloc is used in a lot of places :-) + */ +MPI mpi_alloc(unsigned nlimbs) +{ +	MPI a; + +	a = kmalloc(sizeof *a, GFP_KERNEL); +	if (!a) +		return a; + +	if (nlimbs) { +		a->d = mpi_alloc_limb_space(nlimbs); +		if (!a->d) { +			kfree(a); +			return NULL; +		} +	} else { +		a->d = NULL; +	} + +	a->alloced = nlimbs; +	a->nlimbs = 0; +	a->sign = 0; +	a->flags = 0; +	a->nbits = 0; +	return a; +} +EXPORT_SYMBOL_GPL(mpi_alloc); + +mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs) +{ +	size_t len = nlimbs * sizeof(mpi_limb_t); + +	if (!len) +		return NULL; + +	return kmalloc(len, GFP_KERNEL); +} + +void mpi_free_limb_space(mpi_ptr_t a) +{ +	if (!a) +		return; + +	kfree_sensitive(a); +} + +void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs) +{ +	mpi_free_limb_space(a->d); +	a->d = ap; +	a->alloced = nlimbs; +} + +/**************** + * Resize the array of A to NLIMBS. the additional space is cleared + * (set to 0) [done by m_realloc()] + */ +int mpi_resize(MPI a, unsigned nlimbs) +{ +	void *p; + +	if (nlimbs <= a->alloced) +		return 0;	/* no need to do it */ + +	if (a->d) { +		p = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL); +		if (!p) +			return -ENOMEM; +		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t)); +		kfree_sensitive(a->d); +		a->d = p; +	} else { +		a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL); +		if (!a->d) +			return -ENOMEM; +	} +	a->alloced = nlimbs; +	return 0; +} + +void mpi_clear(MPI a) +{ +	if (!a) +		return; +	a->nlimbs = 0; +	a->flags = 0; +} +EXPORT_SYMBOL_GPL(mpi_clear); + +void mpi_free(MPI a) +{ +	if (!a) +		return; + +	if (a->flags & 4) +		kfree_sensitive(a->d); +	else +		mpi_free_limb_space(a->d); + +	if (a->flags & ~7) +		pr_info("invalid flag value in mpi\n"); +	kfree(a); +} +EXPORT_SYMBOL_GPL(mpi_free); + +/**************** + * Note: This copy function should not interpret the MPI + *	 but copy it transparently. + */ +MPI mpi_copy(MPI a) +{ +	int i; +	MPI b; + +	if (a) { +		b = mpi_alloc(a->nlimbs); +		b->nlimbs = a->nlimbs; +		b->sign = a->sign; +		b->flags = a->flags; +		b->flags &= ~(16|32); /* Reset the immutable and constant flags. */ +		for (i = 0; i < b->nlimbs; i++) +			b->d[i] = a->d[i]; +	} else +		b = NULL; +	return b; +} + +/**************** + * This function allocates an MPI which is optimized to hold + * a value as large as the one given in the argument and allocates it + * with the same flags as A. + */ +MPI mpi_alloc_like(MPI a) +{ +	MPI b; + +	if (a) { +		b = mpi_alloc(a->nlimbs); +		b->nlimbs = 0; +		b->sign = 0; +		b->flags = a->flags; +	} else +		b = NULL; + +	return b; +} + + +/* Set U into W and release U.  If W is NULL only U will be released. */ +void mpi_snatch(MPI w, MPI u) +{ +	if (w) { +		mpi_assign_limb_space(w, u->d, u->alloced); +		w->nlimbs = u->nlimbs; +		w->sign   = u->sign; +		w->flags  = u->flags; +		u->alloced = 0; +		u->nlimbs = 0; +		u->d = NULL; +	} +	mpi_free(u); +} + + +MPI mpi_set(MPI w, MPI u) +{ +	mpi_ptr_t wp, up; +	mpi_size_t usize = u->nlimbs; +	int usign = u->sign; + +	if (!w) +		w = mpi_alloc(mpi_get_nlimbs(u)); +	RESIZE_IF_NEEDED(w, usize); +	wp = w->d; +	up = u->d; +	MPN_COPY(wp, up, usize); +	w->nlimbs = usize; +	w->flags = u->flags; +	w->flags &= ~(16|32); /* Reset the immutable and constant flags.  */ +	w->sign = usign; +	return w; +} +EXPORT_SYMBOL_GPL(mpi_set); + +MPI mpi_set_ui(MPI w, unsigned long u) +{ +	if (!w) +		w = mpi_alloc(1); +	/* FIXME: If U is 0 we have no need to resize and thus possible +	 * allocating the limbs. +	 */ +	RESIZE_IF_NEEDED(w, 1); +	w->d[0] = u; +	w->nlimbs = u ? 1 : 0; +	w->sign = 0; +	w->flags = 0; +	return w; +} +EXPORT_SYMBOL_GPL(mpi_set_ui); + +MPI mpi_alloc_set_ui(unsigned long u) +{ +	MPI w = mpi_alloc(1); +	w->d[0] = u; +	w->nlimbs = u ? 1 : 0; +	w->sign = 0; +	return w; +} + +/**************** + * Swap the value of A and B, when SWAP is 1. + * Leave the value when SWAP is 0. + * This implementation should be constant-time regardless of SWAP. + */ +void mpi_swap_cond(MPI a, MPI b, unsigned long swap) +{ +	mpi_size_t i; +	mpi_size_t nlimbs; +	mpi_limb_t mask = ((mpi_limb_t)0) - swap; +	mpi_limb_t x; + +	if (a->alloced > b->alloced) +		nlimbs = b->alloced; +	else +		nlimbs = a->alloced; +	if (a->nlimbs > nlimbs || b->nlimbs > nlimbs) +		return; + +	for (i = 0; i < nlimbs; i++) { +		x = mask & (a->d[i] ^ b->d[i]); +		a->d[i] = a->d[i] ^ x; +		b->d[i] = b->d[i] ^ x; +	} + +	x = mask & (a->nlimbs ^ b->nlimbs); +	a->nlimbs = a->nlimbs ^ x; +	b->nlimbs = b->nlimbs ^ x; + +	x = mask & (a->sign ^ b->sign); +	a->sign = a->sign ^ x; +	b->sign = b->sign ^ x; +} + +MODULE_DESCRIPTION("Multiprecision maths library"); +MODULE_LICENSE("GPL");  | 
