Merge remote-tracking branch 'hanno/mpi_read_file_underflow' into development

* hanno/mpi_read_file_underflow:
  Fix potential stack underflow in mpi_read_file.
This commit is contained in:
Manuel Pégourié-Gonnard 2017-06-08 19:48:03 +02:00
commit db108ac944
3 changed files with 15 additions and 4 deletions

View file

@ -28,6 +28,8 @@ Bugfix
Found by blaufish. Fixes #641.
* Fix incorrect sign computation in modular exponentiation
when dealing with negative MPI. Found by Guido Vranken.
* Fix potential stack underflow in mpi_read_file.
Found by Guido Vranken.
Changes
* Send fatal alerts in many more cases instead of dropping the connection.

View file

@ -340,7 +340,7 @@ int mbedtls_mpi_write_string( const mbedtls_mpi *X, int radix,
#if defined(MBEDTLS_FS_IO)
/**
* \brief Read X from an opened file
* \brief Read MPI from a line in an opened file
*
* \param X Destination MPI
* \param radix Input numeric base
@ -349,6 +349,15 @@ int mbedtls_mpi_write_string( const mbedtls_mpi *X, int radix,
* \return 0 if successful, MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if
* the file read buffer is too small or a
* MBEDTLS_ERR_MPI_XXX error code
*
* \note On success, this function advances the file stream
* to the end of the current line or to EOF.
*
* The function returns 0 on an empty line.
*
* Leading whitespaces are ignored, as is a
* '0x' prefix for radix 16.
*
*/
int mbedtls_mpi_read_file( mbedtls_mpi *X, int radix, FILE *fin );

View file

@ -616,11 +616,11 @@ int mbedtls_mpi_read_file( mbedtls_mpi *X, int radix, FILE *fin )
if( slen == sizeof( s ) - 2 )
return( MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL );
if( s[slen - 1] == '\n' ) { slen--; s[slen] = '\0'; }
if( s[slen - 1] == '\r' ) { slen--; s[slen] = '\0'; }
if( slen > 0 && s[slen - 1] == '\n' ) { slen--; s[slen] = '\0'; }
if( slen > 0 && s[slen - 1] == '\r' ) { slen--; s[slen] = '\0'; }
p = s + slen;
while( --p >= s )
while( p-- > s )
if( mpi_get_digit( &d, radix, *p ) != 0 )
break;