diff options
Diffstat (limited to 'mpi/mpi-bit.c')
| -rw-r--r-- | mpi/mpi-bit.c | 93 |
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. */ |