Commit 0ae1f402 authored by Paul Bakker's avatar Paul Bakker
Browse files

Allow R and A to point to same mpi in mpi_div_mpi

(cherry picked from commit f02c5642 and
from commit 50546921)
parent f173e0ac
......@@ -12,6 +12,8 @@ Bugfix
#52)
* Fixed possible segfault in mpi_shift_r() (found by Manuel
Pégourié-Gonnard)
* Allow R and A to point to same mpi in mpi_div_mpi (found by Manuel
Pégourié-Gonnard)
Security
* Fixed potential memory zeroization on miscrafted RSA key (found by Eloi
......
......@@ -1196,9 +1196,9 @@ int mpi_div_mpi( mpi *Q, mpi *R, const mpi *A, const mpi *B )
if( R != NULL )
{
mpi_shift_r( &X, k );
X.s = A->s;
mpi_copy( R, &X );
R->s = A->s;
if( mpi_cmp_int( R, 0 ) == 0 )
R->s = 1;
}
......@@ -1399,19 +1399,6 @@ int mpi_exp_mod( mpi *X, const mpi *A, const mpi *E, const mpi *N, mpi *_RR )
if( mpi_cmp_int( E, 0 ) < 0 )
return( POLARSSL_ERR_MPI_BAD_INPUT_DATA );
/*
* Compensate for negative A (and correct at the end)
*/
neg = ( A->s == -1 );
mpi_init( &Apos );
if( neg )
{
MPI_CHK( mpi_copy( &Apos, A ) );
Apos.s = 1;
A = &Apos;
}
/*
* Init temps and window size
*/
......@@ -1432,6 +1419,19 @@ int mpi_exp_mod( mpi *X, const mpi *A, const mpi *E, const mpi *N, mpi *_RR )
MPI_CHK( mpi_grow( &W[1], j ) );
MPI_CHK( mpi_grow( &T, j * 2 ) );
/*
* Compensate for negative A (and correct at the end)
*/
neg = ( A->s == -1 );
mpi_init( &Apos );
if( neg )
{
MPI_CHK( mpi_copy( &Apos, A ) );
Apos.s = 1;
A = &Apos;
}
/*
* If 1st call, pre-compute R^2 mod N
*/
......
......@@ -514,21 +514,21 @@ END_CASE
BEGIN_CASE
mpi_mod_mpi:radix_X:input_X:radix_Y:input_Y:radix_A:input_A:div_result
{
mpi X, Y, Z, A;
mpi X, Y, A;
int res;
mpi_init( &X ); mpi_init( &Y ); mpi_init( &Z ); mpi_init( &A );
mpi_init( &X ); mpi_init( &Y ); mpi_init( &A );
TEST_ASSERT( mpi_read_string( &X, {radix_X}, {input_X} ) == 0 );
TEST_ASSERT( mpi_read_string( &Y, {radix_Y}, {input_Y} ) == 0 );
TEST_ASSERT( mpi_read_string( &A, {radix_A}, {input_A} ) == 0 );
res = mpi_mod_mpi( &Z, &X, &Y );
res = mpi_mod_mpi( &X, &X, &Y );
TEST_ASSERT( res == {div_result} );
if( res == 0 )
{
TEST_ASSERT( mpi_cmp_mpi( &Z, &A ) == 0 );
TEST_ASSERT( mpi_cmp_mpi( &X, &A ) == 0 );
}
mpi_free( &X ); mpi_free( &Y ); mpi_free( &Z ); mpi_free( &A );
mpi_free( &X ); mpi_free( &Y ); mpi_free( &A );
}
END_CASE
......
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