243 lines
5.9 KiB
C
243 lines
5.9 KiB
C
/*
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* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdlib.h>
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#include <errno.h>
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#include <assert.h>
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#include <ipxe/asn1.h>
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#include <ipxe/base64.h>
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#include <ipxe/uaccess.h>
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#include <ipxe/image.h>
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#include <ipxe/pem.h>
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/** @file
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*
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* PEM-encoded ASN.1 data
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*
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*/
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/**
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* Locate next line
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*
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* @v data PEM data
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* @v len Length of PEM data
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* @v offset Starting offset
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* @ret next Offset to next line
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*/
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static size_t pem_next ( userptr_t data, size_t len, size_t offset ) {
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off_t eol;
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/* Find and skip next newline character, if any */
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eol = memchr_user ( data, offset, '\n', ( len - offset ) );
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if ( eol < 0 )
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return len;
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return ( eol + 1 );
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}
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/**
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* Locate boundary marker line
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*
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* @v data PEM data
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* @v len Length of PEM data
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* @v offset Starting offset
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* @v marker Boundary marker
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* @ret offset Offset to boundary marker line, or negative error
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*/
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static int pem_marker ( userptr_t data, size_t len, size_t offset,
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const char *marker ) {
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char buf[ strlen ( marker ) ];
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/* Sanity check */
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assert ( offset <= len );
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/* Scan for marker at start of line */
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while ( offset < len ) {
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/* Check for marker */
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if ( ( len - offset ) < sizeof ( buf ) )
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break;
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copy_from_user ( buf, data, offset, sizeof ( buf ) );
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if ( memcmp ( buf, marker, sizeof ( buf ) ) == 0 )
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return offset;
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/* Move to next line */
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offset = pem_next ( data, len, offset );
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assert ( offset <= len );
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}
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return -ENOENT;
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}
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/**
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* Extract ASN.1 object from PEM data
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*
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* @v data PEM data
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* @v len Length of PEM data
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* @v offset Offset within data
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* @v cursor ASN.1 cursor to fill in
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* @ret next Offset to next object, or negative error
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*
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* The caller is responsible for eventually calling free() on the
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* allocated ASN.1 cursor.
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*/
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int pem_asn1 ( userptr_t data, size_t len, size_t offset,
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struct asn1_cursor **cursor ) {
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size_t encoded_len;
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size_t decoded_max_len;
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char *encoded;
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void *decoded;
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int decoded_len;
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int begin;
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int end;
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int rc;
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/* Locate and skip BEGIN marker */
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begin = pem_marker ( data, len, offset, PEM_BEGIN );
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if ( begin < 0 ) {
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rc = begin;
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DBGC ( data, "PEM [%#zx,%#zx) missing BEGIN marker: %s\n",
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offset, len, strerror ( rc ) );
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goto err_begin;
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}
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begin = pem_next ( data, len, begin );
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/* Locate and skip END marker */
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end = pem_marker ( data, len, begin, PEM_END );
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if ( end < 0 ) {
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rc = end;
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DBGC ( data, "PEM [%#zx,%#zx) missing END marker: %s\n",
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offset, len, strerror ( rc ) );
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goto err_end;
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}
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encoded_len = ( end - begin );
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end = pem_next ( data, len, end );
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/* Extract Base64-encoded data */
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encoded = malloc ( encoded_len + 1 /* NUL */ );
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if ( ! encoded ) {
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rc = -ENOMEM;
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goto err_alloc_encoded;
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}
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copy_from_user ( encoded, data, begin, encoded_len );
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encoded[encoded_len] = '\0';
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/* Allocate cursor and data buffer */
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decoded_max_len = base64_decoded_max_len ( encoded );
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*cursor = malloc ( sizeof ( **cursor ) + decoded_max_len );
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if ( ! *cursor ) {
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rc = -ENOMEM;
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goto err_alloc_cursor;
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}
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decoded = ( ( ( void * ) *cursor ) + sizeof ( **cursor ) );
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/* Decode Base64-encoded data */
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decoded_len = base64_decode ( encoded, decoded, decoded_max_len );
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if ( decoded_len < 0 ) {
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rc = decoded_len;
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DBGC ( data, "PEM could not decode: %s\n", strerror ( rc ) );
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goto err_decode;
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}
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(*cursor)->data = decoded;
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(*cursor)->len = decoded_len;
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assert ( (*cursor)->len <= decoded_max_len );
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/* Free Base64-encoded data */
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free ( encoded );
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/* Update offset and skip any unencapsulated trailer */
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offset = end;
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if ( pem_marker ( data, len, offset, PEM_BEGIN ) < 0 )
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offset = len;
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return offset;
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err_decode:
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free ( *cursor );
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*cursor = NULL;
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err_alloc_cursor:
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free ( encoded );
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err_alloc_encoded:
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err_end:
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err_begin:
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return rc;
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}
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/**
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* Probe PEM image
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*
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* @v image PEM image
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* @ret rc Return status code
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*/
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static int pem_image_probe ( struct image *image ) {
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int offset;
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int rc;
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/* Check that image contains a BEGIN marker */
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if ( ( offset = pem_marker ( image->data, image->len, 0,
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PEM_BEGIN ) ) < 0 ) {
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rc = offset;
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DBGC ( image, "PEM %s has no BEGIN marker: %s\n",
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image->name, strerror ( rc ) );
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return rc;
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}
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return 0;
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}
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/**
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* Extract ASN.1 object from image
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*
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* @v image PEM image
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* @v offset Offset within image
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* @v cursor ASN.1 cursor to fill in
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* @ret next Offset to next image, or negative error
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*
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* The caller is responsible for eventually calling free() on the
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* allocated ASN.1 cursor.
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*/
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static int pem_image_asn1 ( struct image *image, size_t offset,
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struct asn1_cursor **cursor ) {
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int next;
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int rc;
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/* Extract ASN.1 object */
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if ( ( next = pem_asn1 ( image->data, image->len, offset,
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cursor ) ) < 0 ) {
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rc = next;
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DBGC ( image, "PEM %s could not extract ASN.1: %s\n",
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image->name, strerror ( rc ) );
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return rc;
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}
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return next;
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}
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/** PEM image type */
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struct image_type pem_image_type __image_type ( PROBE_NORMAL ) = {
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.name = "PEM",
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.probe = pem_image_probe,
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.asn1 = pem_image_asn1,
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};
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