sysadmin/ipxe
1
0
Fork 0
mirror of https://github.com/ipxe/ipxe synced 2026-02-28 03:11:18 +03:00
Code Issues Packages Projects Releases Wiki Activity

[crypto] Add functions for constructing ASN.1 objects

Browse Source 
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2012-05-11 16:40:28 +01:00
parent e01af7367d
commit deac4ea1ba
2 changed files with 172 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

139
src/crypto/asn1.c
View File

@@ -20,6 +20,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
@@ -699,3 +700,141 @@ int asn1_generalized_time ( const struct asn1_cursor *cursor, time_t *time ) {
return 0;
}
/**
* Construct ASN.1 header
*
* @v header ASN.1 builder header
* @v type Type
* @v len Content length
* @ret header_len Header length
*/
static size_t asn1_header ( struct asn1_builder_header *header,
unsigned int type, size_t len ) {
unsigned int header_len = 2;
unsigned int len_len = 0;
size_t temp;
/* Construct header */
header->type = type;
if ( len < 0x80 ) {
header->length[0] = len;
} else {
for ( temp = len ; temp ; temp >>= 8 )
len_len++;
header->length[0] = ( 0x80 | len_len );
header_len += len_len;
for ( temp = len ; temp ; temp >>= 8 )
header->length[len_len--] = ( temp & 0xff );
}
return header_len;
}
/**
* Grow ASN.1 builder
*
* @v builder ASN.1 builder
* @v extra Extra space to prepend
* @ret rc Return status code
*/
static int asn1_grow ( struct asn1_builder *builder, size_t extra ) {
size_t new_len;
void *new;
/* As with the ASN1 parsing functions, make errors permanent */
if ( builder->len && ! builder->data )
return -ENOMEM;
/* Reallocate data buffer */
new_len = ( builder->len + extra );
new = realloc ( builder->data, new_len );
if ( ! new ) {
free ( builder->data );
builder->data = NULL;
return -ENOMEM;
}
builder->data = new;
/* Move existing data to end of buffer */
memmove ( ( builder->data + extra ), builder->data, builder->len );
builder->len = new_len;
return 0;
}
/**
* Prepend raw data to ASN.1 builder
*
* @v builder ASN.1 builder
* @v data Data to prepend
* @v len Length of data to prepend
* @ret rc Return status code
*/
int asn1_prepend_raw ( struct asn1_builder *builder, const void *data,
size_t len ) {
int rc;
/* Grow buffer */
if ( ( rc = asn1_grow ( builder, len ) ) != 0 )
return rc;
/* Populate data buffer */
memcpy ( builder->data, data, len );
return 0;
}
/**
* Prepend data to ASN.1 builder
*
* @v builder ASN.1 builder
* @v type Type
* @v data Data to prepend
* @v len Length of data to prepend
* @ret rc Return status code
*/
int asn1_prepend ( struct asn1_builder *builder, unsigned int type,
const void *data, size_t len ) {
struct asn1_builder_header header;
size_t header_len;
int rc;
/* Construct header */
header_len = asn1_header ( &header, type, len );
/* Grow buffer */
if ( ( rc = asn1_grow ( builder, header_len + len ) ) != 0 )
return rc;
/* Populate data buffer */
memcpy ( builder->data, &header, header_len );
memcpy ( ( builder->data + header_len ), data, len );
return 0;
}
/**
* Wrap ASN.1 builder
*
* @v builder ASN.1 builder
* @v type Type
* @ret rc Return status code
*/
int asn1_wrap ( struct asn1_builder *builder, unsigned int type ) {
struct asn1_builder_header header;
size_t header_len;
int rc;
/* Construct header */
header_len = asn1_header ( &header, type, builder->len );
/* Grow buffer */
if ( ( rc = asn1_grow ( builder, header_len ) ) != 0 )
return rc;
/* Populate data buffer */
memcpy ( builder->data, &header, header_len );
return 0;
}