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https://github.com/brain-hackers/linux-brain.git
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6b10d3d3a9
[ Upstream commit b6f756726e4dfe75be1883f6a0202dcecdc801ab ]
We should set the additional space to 0 in mpi_resize().
So use kcalloc() instead of kmalloc_array().
In lib/mpi/ec.c:
/****************
* 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)
Like the comment of kernel's mpi_resize() said, the additional space
need to be set to 0, but when a->d is not NULL, it does not set.
The kernel's mpi lib is from libgcrypt, the mpi resize in libgcrypt
is _gcry_mpi_resize() which set the additional space to 0.
This bug may cause mpi api which use mpi_resize() get wrong result
under the condition of using the additional space without initiation.
If this condition is not met, the bug would not be triggered.
Currently in kernel, rsa, sm2 and dh use mpi lib, and they works well,
so the bug is not triggered in these cases.
add_points_edwards() use the additional space directly, so it will
get a wrong result.
Fixes: cdec9cb516 ("crypto: GnuPG based MPI lib - source files (part 1)")
Signed-off-by: Hongbo Li <herberthbli@tencent.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
127 lines
2.7 KiB
C
127 lines
2.7 KiB
C
/* mpiutil.ac - Utility functions for MPI
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* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#include "mpi-internal.h"
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/****************
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* Note: It was a bad idea to use the number of limbs to allocate
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* because on a alpha the limbs are large but we normally need
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* integers of n bits - So we should chnage this to bits (or bytes).
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*
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* But mpi_alloc is used in a lot of places :-)
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*/
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MPI mpi_alloc(unsigned nlimbs)
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{
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MPI a;
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a = kmalloc(sizeof *a, GFP_KERNEL);
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if (!a)
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return a;
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if (nlimbs) {
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a->d = mpi_alloc_limb_space(nlimbs);
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if (!a->d) {
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kfree(a);
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return NULL;
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}
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} else {
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a->d = NULL;
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}
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a->alloced = nlimbs;
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a->nlimbs = 0;
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a->sign = 0;
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a->flags = 0;
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a->nbits = 0;
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return a;
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}
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EXPORT_SYMBOL_GPL(mpi_alloc);
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mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs)
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{
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size_t len = nlimbs * sizeof(mpi_limb_t);
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if (!len)
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return NULL;
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return kmalloc(len, GFP_KERNEL);
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}
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void mpi_free_limb_space(mpi_ptr_t a)
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{
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if (!a)
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return;
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kzfree(a);
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}
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void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
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{
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mpi_free_limb_space(a->d);
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a->d = ap;
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a->alloced = nlimbs;
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}
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/****************
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* Resize the array of A to NLIMBS. the additional space is cleared
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* (set to 0) [done by m_realloc()]
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*/
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int mpi_resize(MPI a, unsigned nlimbs)
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{
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void *p;
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if (nlimbs <= a->alloced)
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return 0; /* no need to do it */
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if (a->d) {
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p = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
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if (!p)
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return -ENOMEM;
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memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
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kzfree(a->d);
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a->d = p;
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} else {
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a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
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if (!a->d)
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return -ENOMEM;
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}
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a->alloced = nlimbs;
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return 0;
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}
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void mpi_free(MPI a)
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{
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if (!a)
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return;
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if (a->flags & 4)
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kzfree(a->d);
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else
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mpi_free_limb_space(a->d);
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if (a->flags & ~7)
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pr_info("invalid flag value in mpi\n");
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kfree(a);
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}
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EXPORT_SYMBOL_GPL(mpi_free);
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MODULE_DESCRIPTION("Multiprecision maths library");
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MODULE_LICENSE("GPL");
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