der.c File Reference

DER-encoded ASN.1 data. More...

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/asn1.h>
#include <ipxe/der.h>
#include <ipxe/image.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
int	der_asn1 (const void *data, size_t len, size_t offset, struct asn1_cursor **cursor)
	Extract ASN.1 object from DER data. More...
static int	der_image_probe (struct image *image)
	Probe DER image. More...
static int	der_image_asn1 (struct image *image, size_t offset, struct asn1_cursor **cursor)
	Extract ASN.1 object from DER image. More...
struct image_type der_image_type	__image_type (PROBE_NORMAL)
	DER image type. More...

Detailed Description

DER-encoded ASN.1 data.

Definition in file der.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

der_asn1()

int der_asn1	(	const void *	data,
		size_t	len,
		size_t	offset,
		struct asn1_cursor **	cursor
	)

Extract ASN.1 object from DER data.

Parameters

data	DER data
len	Length of DER data
offset	Offset within data
cursor	ASN.1 cursor to fill in

Return values

next	Offset to next object, or negative error

The caller is responsible for eventually calling free() on the allocated ASN.1 cursor.

Definition at line 53 of file der.c.

                                             {
        size_t remaining;
        void *raw;

        /* Sanity check */
        assert ( offset <= len );
        remaining = ( len - offset );

        /* Allocate cursor and data buffer */
        *cursor = malloc ( sizeof ( **cursor ) + remaining );
        if ( ! *cursor )
                return -ENOMEM;
        raw = ( ( ( void * ) *cursor ) + sizeof ( **cursor ) );

        /* Populate cursor and data buffer */
        (*cursor)->data = raw;
        (*cursor)->len = remaining;
        memcpy ( raw, ( data + offset ), remaining );

        /* Shrink cursor */
        asn1_shrink_any ( *cursor );

        return ( offset + (*cursor)->len );
}

References asn1_shrink_any(), assert(), data, ENOMEM, len, malloc(), memcpy(), offset, and raw.

Referenced by der_image_asn1(), and efisig_asn1().

der_image_probe()

static int der_image_probe ( struct image *  image )

static

Probe DER image.

Parameters

image

DER image

Return values

rc	Return status code

Definition at line 85 of file der.c.

                                                   {
        struct asn1_cursor cursor;
        int rc;

        /* Prepare cursor */
        cursor.data = image->data;
        cursor.len = image->len;

        /* Check that image begins with an ASN.1 sequence object */
        if ( ( rc = asn1_skip ( &cursor, ASN1_SEQUENCE ) ) != 0 ) {
                DBGC ( image, "DER %s is not valid ASN.1: %s\n",
                       image->name, strerror ( rc ) );
                return rc;
        }

        /* Check that image comprises a single well-formed ASN.1 object */
        if ( cursor.len ) {
                DBGC ( image, "DER %s is not single ASN.1\n", image->name );
                return -ENOEXEC;
        }

        return 0;
}

References ASN1_SEQUENCE, asn1_skip(), asn1_cursor::data, image::data, DBGC, ENOEXEC, asn1_cursor::len, image::len, image::name, rc, and strerror().

der_image_asn1()

static int der_image_asn1 ( struct image *  image, size_t  offset, struct asn1_cursor **  cursor  )

static

Extract ASN.1 object from DER image.

Parameters

image	DER image
offset	Offset within image
cursor	ASN.1 cursor to fill in

Return values

next	Offset to next image, or negative error

The caller is responsible for eventually calling free() on the allocated ASN.1 cursor.

Definition at line 120 of file der.c.

                                                          {
        int next;
        int rc;

        /* Extract ASN.1 object */
        if ( ( next = der_asn1 ( image->data, image->len, offset,
                                 cursor ) ) < 0 ) {
                rc = next;
                DBGC ( image, "DER %s could not extract ASN.1: %s\n",
                       image->name, strerror ( rc ) );
                return rc;
        }

        return next;
}

References image::data, DBGC, der_asn1(), image::len, image::name, next, offset, rc, and strerror().

__image_type()

struct image_type zimg_image_type __image_type

(

PROBE_NORMAL

)

Initial value:

= {
        .name = "zimg",
        .probe = zimg_probe,
        .extract = zimg_extract,
        .exec = image_extract_exec,
}

DER image type.

Linux kernel compressed image type.