Fix potential buffer overflow in asn1write

This commit is contained in:
Manuel Pégourié-Gonnard 2015-10-21 12:07:47 +02:00
parent 9dc66f4b2f
commit 0d66bb959f
2 changed files with 7 additions and 3 deletions

View file

@ -9,6 +9,10 @@ Security
* Fix potential heap corruption on Windows when
mbedtls_x509_crt_parse_path() is passed a path longer than 2GB. Cannot be
triggered remotely. Found by Guido Vranken, Interlworks.
* Fix potential buffer overflow in some asn1_write_xxx() functions.
Cannot be triggered remotely unless you create X.509 certificates based
on untrusted input or write keys of untrusted origin. Found by Guido
Vranken, Interlworks.
* The X509 max_pathlen constraint was not enforced on intermediate
certificates. Found by Nicholas Wilson, fix and tests provided by
Janos Follath. #280 and #319

View file

@ -87,7 +87,7 @@ int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
{
size_t len = 0;
if( *p - start < (int) size )
if( *p < start || (size_t)( *p - start ) < size )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
len = size;
@ -107,7 +107,7 @@ int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedt
//
len = mbedtls_mpi_size( X );
if( *p - start < (int) len )
if( *p < start || (size_t)( *p - start ) < len )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
(*p) -= len;
@ -270,7 +270,7 @@ int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,
// Calculate byte length
//
if( *p - start < (int) size + 1 )
if( *p < start || (size_t)( *p - start ) < size + 1 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
len = size + 1;