der.c File Reference

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

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

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static int	der_asn1 (struct image *image, size_t offset __unused, struct asn1_cursor **cursor)
	Extract ASN.1 object from image. More...
static int	der_probe (struct image *image)
	Probe 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

)

der_asn1()

static int der_asn1 ( struct image *  image, size_t offset  __unused, struct asn1_cursor **  cursor  )

static

Extract ASN.1 object from 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 51 of file der.c.

                                                    {
        void *data;

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

        /* Populate cursor and data buffer */
        (*cursor)->data = data;
        (*cursor)->len = image->len;
        copy_from_user ( data, image->data, 0, image->len );

        return image->len;
}

References copy_from_user(), data, image::data, ENOMEM, image::len, and malloc().

der_probe()

static int der_probe ( struct image *  image )

static

Probe DER image.

Parameters

image

DER image

Return values

rc	Return status code

Definition at line 75 of file der.c.

                                             {
        struct asn1_cursor cursor;
        uint8_t buf[8];
        size_t extra;
        int rc;

        /* Sanity check: no realistic DER image can be smaller than this */
        if ( image->len < sizeof ( buf ) )
                return -ENOEXEC;

        /* Prepare partial cursor */
        cursor.data = buf;
        cursor.len = sizeof ( buf );
        copy_from_user ( buf, image->data, 0, sizeof ( buf ) );
        extra = ( image->len - sizeof ( buf ) );

        /* Check that image begins with an ASN.1 sequence object */
        if ( ( rc = asn1_enter_partial ( &cursor, ASN1_SEQUENCE,
                                         &extra ) ) != 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 ( extra != ( image->len - sizeof ( buf ) ) ) {
                DBGC ( image, "DER %s is not single ASN.1\n", image->name );
                return -ENOEXEC;
        }

        return 0;
}

References asn1_enter_partial(), ASN1_SEQUENCE, copy_from_user(), asn1_cursor::data, image::data, DBGC, ENOEXEC, extra, asn1_cursor::len, image::len, image::name, rc, and strerror().

__image_type()

struct image_type der_image_type __image_type

(

PROBE_NORMAL

)

DER image type.