lib/mbedtls
1
0
Fork 0
mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-07-29 11:41:15 +03:00
Code Activity

Add mbedtls_asn1_write_len() support for 3 and 4 byte lengths

Browse Source 
As a consequence also adds coverage for reading 3 and 4 byte lengths
(which were not covered before)
This commit is contained in:
Paul Bakker
2016-07-14 11:39:56 +01:00
committed by Simon Butcher
parent 5e8b77cd8c
commit c7d6bd4b5f
3 changed files with 52 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
library/asn1write.c
View File

@ -41,11 +41,6 @@
int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
{
// We don't support lengths over 65535 for now
//
if( len > 0xFFFF )
return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
if( len < 0x80 )
{
if( *p - start < 1 )
@ -65,14 +60,43 @@ int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len
return( 2 );
}
if( *p - start < 3 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
if( len <= 0xFFFF )
{
if( *p - start < 3 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = len % 256;
*--(*p) = ( len / 256 ) % 256;
*--(*p) = 0x82;
*--(*p) = ( len ) & 0xFF;
*--(*p) = ( len >> 8 ) & 0xFF;
*--(*p) = 0x82;
return( 3 );
}
return( 3 );
if( len <= 0xFFFFFF )
{
if( *p - start < 4 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = ( len ) & 0xFF;
*--(*p) = ( len >> 8 ) & 0xFF;
*--(*p) = ( len >> 16 ) & 0xFF;
*--(*p) = 0x83;
return( 4 );
}
if( len <= 0xFFFFFFFF )
{
if( *p - start < 5 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = ( len ) & 0xFF;
*--(*p) = ( len >> 8 ) & 0xFF;
*--(*p) = ( len >> 16 ) & 0xFF;
*--(*p) = ( len >> 24 ) & 0xFF;
*--(*p) = 0x84;
return( 5 );
}
return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
}
int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )