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-rw-r--r--mpi/mpi-bit.c93
1 files changed, 68 insertions, 25 deletions
diff --git a/mpi/mpi-bit.c b/mpi/mpi-bit.c
index cdc6b0b3..74042e89 100644
--- a/mpi/mpi-bit.c
+++ b/mpi/mpi-bit.c
@@ -1,5 +1,6 @@
/* mpi-bit.c - MPI bit level functions
* Copyright (C) 1998, 1999, 2001, 2002, 2006 Free Software Foundation, Inc.
+ * Copyright (C) 2013 g10 Code GmbH
*
* This file is part of Libgcrypt.
*
@@ -117,6 +118,12 @@ gcry_mpi_set_bit( gcry_mpi_t a, unsigned int n )
{
unsigned int limbno, bitno;
+ if (mpi_is_immutable (a))
+ {
+ mpi_immutable_failed ();
+ return;
+ }
+
limbno = n / BITS_PER_MPI_LIMB;
bitno = n % BITS_PER_MPI_LIMB;
@@ -136,6 +143,12 @@ gcry_mpi_set_highbit( gcry_mpi_t a, unsigned int n )
{
unsigned int limbno, bitno;
+ if (mpi_is_immutable (a))
+ {
+ mpi_immutable_failed ();
+ return;
+ }
+
limbno = n / BITS_PER_MPI_LIMB;
bitno = n % BITS_PER_MPI_LIMB;
@@ -156,18 +169,23 @@ gcry_mpi_set_highbit( gcry_mpi_t a, unsigned int n )
void
gcry_mpi_clear_highbit( gcry_mpi_t a, unsigned int n )
{
- unsigned int limbno, bitno;
+ unsigned int limbno, bitno;
- limbno = n / BITS_PER_MPI_LIMB;
- bitno = n % BITS_PER_MPI_LIMB;
+ if (mpi_is_immutable (a))
+ {
+ mpi_immutable_failed ();
+ return;
+ }
- if( limbno >= a->nlimbs )
- return; /* not allocated, therefore no need to clear bits
- :-) */
+ limbno = n / BITS_PER_MPI_LIMB;
+ bitno = n % BITS_PER_MPI_LIMB;
+
+ if( limbno >= a->nlimbs )
+ return; /* not allocated, therefore no need to clear bits :-) */
- for( ; bitno < BITS_PER_MPI_LIMB; bitno++ )
- a->d[limbno] &= ~(A_LIMB_1 << bitno);
- a->nlimbs = limbno+1;
+ for( ; bitno < BITS_PER_MPI_LIMB; bitno++ )
+ a->d[limbno] &= ~(A_LIMB_1 << bitno);
+ a->nlimbs = limbno+1;
}
/****************
@@ -176,14 +194,20 @@ gcry_mpi_clear_highbit( gcry_mpi_t a, unsigned int n )
void
gcry_mpi_clear_bit( gcry_mpi_t a, unsigned int n )
{
- unsigned int limbno, bitno;
+ unsigned int limbno, bitno;
- limbno = n / BITS_PER_MPI_LIMB;
- bitno = n % BITS_PER_MPI_LIMB;
+ if (mpi_is_immutable (a))
+ {
+ mpi_immutable_failed ();
+ return;
+ }
- if( limbno >= a->nlimbs )
- return; /* don't need to clear this bit, it's to far to left */
- a->d[limbno] &= ~(A_LIMB_1 << bitno);
+ limbno = n / BITS_PER_MPI_LIMB;
+ bitno = n % BITS_PER_MPI_LIMB;
+
+ if (limbno >= a->nlimbs)
+ return; /* Don't need to clear this bit, it's far too left. */
+ a->d[limbno] &= ~(A_LIMB_1 << bitno);
}
@@ -194,19 +218,26 @@ gcry_mpi_clear_bit( gcry_mpi_t a, unsigned int n )
void
_gcry_mpi_rshift_limbs( gcry_mpi_t a, unsigned int count )
{
- mpi_ptr_t ap = a->d;
- mpi_size_t n = a->nlimbs;
- unsigned int i;
+ mpi_ptr_t ap = a->d;
+ mpi_size_t n = a->nlimbs;
+ unsigned int i;
- if( count >= n ) {
- a->nlimbs = 0;
- return;
+ if (mpi_is_immutable (a))
+ {
+ mpi_immutable_failed ();
+ return;
}
- for( i = 0; i < n - count; i++ )
- ap[i] = ap[i+count];
- ap[i] = 0;
- a->nlimbs -= count;
+ if (count >= n)
+ {
+ a->nlimbs = 0;
+ return;
+ }
+
+ for( i = 0; i < n - count; i++ )
+ ap[i] = ap[i+count];
+ ap[i] = 0;
+ a->nlimbs -= count;
}
@@ -221,6 +252,12 @@ gcry_mpi_rshift ( gcry_mpi_t x, gcry_mpi_t a, unsigned int n )
unsigned int nlimbs = (n/BITS_PER_MPI_LIMB);
unsigned int nbits = (n%BITS_PER_MPI_LIMB);
+ if (mpi_is_immutable (x))
+ {
+ mpi_immutable_failed ();
+ return;
+ }
+
if ( x == a )
{
/* In-place operation. */
@@ -328,6 +365,12 @@ gcry_mpi_lshift ( gcry_mpi_t x, gcry_mpi_t a, unsigned int n )
unsigned int nlimbs = (n/BITS_PER_MPI_LIMB);
unsigned int nbits = (n%BITS_PER_MPI_LIMB);
+ if (mpi_is_immutable (x))
+ {
+ mpi_immutable_failed ();
+ return;
+ }
+
if (x == a && !n)
return; /* In-place shift with an amount of zero. */