Provisory new pseudo path for El Torito boot images:

--interval:appened_partition_N:all::

libisofs/ecma119.c

@@ -104,6 +104,8 @@ void ecma119_image_free(Ecma119Image *t)
         free(t->output_charset);
     if (t->bootsrc != NULL)
         free(t->bootsrc);
+    if (t->boot_appended_idx != NULL)
+        free(t->boot_appended_idx);
     if (t->system_area_data != NULL)
         free(t->system_area_data);
     if (t->checksum_ctx != NULL) { /* dispose checksum context */
@@ -567,8 +569,13 @@ int ecma119_writer_write_vol_desc(IsoImageWriter *writer)
     vol.vol_desc_version[0] = 1;
     strncpy_pad((char*)vol.system_id, system_id, 32);
     strncpy_pad((char*)vol.volume_id, vol_id, 32);
-    iso_bb(vol.vol_space_size, t->vol_space_size  - t->eff_partition_offset,
+    if (t->pvd_size_is_total_size) {
-           4);
+        iso_bb(vol.vol_space_size,
+               t->total_size / 2048 - t->eff_partition_offset, 4);
+    } else {
+        iso_bb(vol.vol_space_size,
+               t->vol_space_size - t->eff_partition_offset, 4);
+    }
     iso_bb(vol.vol_set_size, (uint32_t) 1, 2);
     iso_bb(vol.vol_seq_number, (uint32_t) 1, 2);
     iso_bb(vol.block_size, (uint32_t) BLOCK_SIZE, 2);
@@ -2376,12 +2383,16 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *in_opts, Ecma119Image **img)
         target->num_bootsrc = target->catalog->num_bootimages;
         target->bootsrc = calloc(target->num_bootsrc + 1,
                                     sizeof(IsoFileSrc *));
-        if (target->bootsrc == NULL) {
+        target->boot_appended_idx = calloc(target->num_bootsrc + 1,
+                                           sizeof(int));
+        if (target->bootsrc == NULL || target->boot_appended_idx == NULL) {
             ret = ISO_OUT_OF_MEM;
             goto target_cleanup;
         }
-        for (i= 0; i < target->num_bootsrc; i++)
+        for (i= 0; i < target->num_bootsrc; i++) {
             target->bootsrc[i] = NULL;
+            target->boot_appended_idx[i] = -1;
+        }
     } else {
         target->num_bootsrc = 0;
         target->bootsrc = NULL;
@@ -2448,6 +2459,10 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *in_opts, Ecma119Image **img)
         goto target_cleanup;
     }
 
+    target->total_size = 0;
+    target->vol_space_size = 0;
+    target->pvd_size_is_total_size = 0;
+
     target->checksum_idx_counter = 0;
     target->checksum_ctx = NULL;
     target->checksum_counter = 0;

libisofs/ecma119.h

@@ -554,10 +554,19 @@ struct ecma119_image
 
     time_t now; /**< Time at which writing began. */
 
-    /** Total size of the output. This only includes the current volume. */
+    /* Total size of the output. Counted in bytes.
+     * Includes ISO filesystem and appended data.
+     */
     off_t total_size;
+
+    /** Size actually governed by the ISO filesystem part of the output */
     uint32_t vol_space_size;
 
+    /* 1= write the total size into the PVD of the ISO,
+     * 0= write vol_space_size
+     */
+    int pvd_size_is_total_size;
+
     /* Bytes already written to image output */
     off_t bytes_written;
     /* just for progress notification */
@@ -640,6 +649,8 @@ struct ecma119_image
     int num_bootsrc;
     IsoFileSrc **bootsrc; /* location of the boot images in the new image */
 
+    int *boot_appended_idx; /* Appended partition which serve as boot images */
+
     /*
      * System Area related information
      */

libisofs/eltorito.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
- * Copyright (c) 2010 - 2014 Thomas Schmitt
+ * Copyright (c) 2010 - 2015 Thomas Schmitt
  *
  * This file is part of the libisofs project; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version 2 
@@ -19,6 +19,7 @@
 #include "image.h"
 #include "messages.h"
 #include "writer.h"
+#include "ecma119.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -323,36 +324,61 @@ int create_image(IsoImage *image, const char *image_path,
     struct el_torito_boot_image *boot;
     int boot_media_type = 0;
     int load_sectors = 0; /* number of sector to load */
+    int part_idx = -1;
     unsigned char partition_type = 0;
     off_t size;
-    IsoNode *imgfile;
+    IsoNode *imgfile = NULL;
-    IsoStream *stream;
+    IsoStream *stream = NULL;
 
     *bootnode = NULL;
-    ret = iso_tree_path_to_node(image, image_path, &imgfile);
+
-    if (ret < 0) {
+    if (strncmp(image_path, "--interval:appended_partition_", 30) == 0) {
-        return ret;
+        /* --interval:appended_partition_N... */ 
-    }
+        if (type != ELTORITO_NO_EMUL) {
-    if (ret == 0) {
+
-        iso_msg_submit(image->id, ISO_NODE_DOESNT_EXIST, 0,
+            /* >>> ??? lift this ban by making a temporary IsoStream from
+                       partition source, determine size,
+                       and read ELTORITO_HARD_DISC_EMUL MBR ?
+             */
+
+            iso_msg_submit(image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
+                           "Appended partition cannot serve as El Torito boot image with FD/HD emulation");
+            return ISO_BOOT_IMAGE_NOT_VALID;
+        }
+        sscanf(image_path + 30, "%d", &part_idx);
+        if (part_idx < 1 || part_idx > ISO_MAX_PARTITIONS) {
+            iso_msg_submit(image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
+          "Appended partition index for El Torito boot image is out of range");
+            return ISO_BOOT_IMAGE_NOT_VALID;
+        }
+        part_idx--;
+        size = 1;
+    } else {
+        ret = iso_tree_path_to_node(image, image_path, &imgfile);
+        if (ret < 0) {
+            return ret;
+        }
+        if (ret == 0) {
+            iso_msg_submit(image->id, ISO_NODE_DOESNT_EXIST, 0,
                        "El Torito boot image file missing in ISO image: '%s'",
                        image_path);
-        return ISO_NODE_DOESNT_EXIST;
+            return ISO_NODE_DOESNT_EXIST;
+        }
+
+        if (imgfile->type != LIBISO_FILE) {
+            return ISO_BOOT_IMAGE_NOT_VALID;
+        }
+        *bootnode = (IsoFile *) imgfile;
+
+        stream = ((IsoFile*)imgfile)->stream;
+
+        /* we need to read the image at least two times */
+        if (!iso_stream_is_repeatable(stream)) {
+            return ISO_BOOT_IMAGE_NOT_VALID;
+        }
+
+        size = iso_stream_get_size(stream);
     }
-
-    if (imgfile->type != LIBISO_FILE) {
-        return ISO_BOOT_IMAGE_NOT_VALID;
-    }
-    *bootnode = (IsoFile *) imgfile;
-
-    stream = ((IsoFile*)imgfile)->stream;
-
-    /* we need to read the image at least two times */
-    if (!iso_stream_is_repeatable(stream)) {
-        return ISO_BOOT_IMAGE_NOT_VALID;
-    }
-
-    size = iso_stream_get_size(stream);
     if (size <= 0) {
         iso_msg_submit(image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
                        "Boot image file is empty");
@@ -441,7 +467,9 @@ int create_image(IsoImage *image, const char *image_path,
         return ISO_OUT_OF_MEM;
     }
     boot->image = (IsoFile*)imgfile;
-    iso_node_ref(imgfile); /* get our ref */
+    boot->appended_idx = part_idx;
+    if (imgfile != NULL)
+        iso_node_ref(imgfile); /* get our ref */
     boot->bootable = 1;
     boot->seems_boot_info_table = 0;
     boot->seems_grub2_boot_info = 0;
@@ -538,8 +566,9 @@ int iso_image_set_boot_image(IsoImage *image, const char *image_path,
         catalog->bootimages[i] = NULL;
     catalog->node = cat_node;
     catalog->sort_weight = 1000000000;                          /* very high */
-    if (!(boot_node->explicit_weight || boot_node->from_old_session))
+    if (boot_node != NULL)
-        boot_node->sort_weight = 2;
+        if (!(boot_node->explicit_weight || boot_node->from_old_session))
+            boot_node->sort_weight = 2;
     iso_node_ref((IsoNode*)cat_node);
     image->bootcat = catalog;
 
@@ -555,7 +584,8 @@ boot_image_cleanup:;
         iso_node_unref((IsoNode*)cat_node);
     }
     if (boot_image) {
-        iso_node_unref((IsoNode*)boot_image->image);
+        if (boot_image->image != NULL)
+            iso_node_unref((IsoNode*)boot_image->image);
         free(boot_image);
     }
     return ret;
@@ -719,8 +749,9 @@ int iso_image_add_boot_image(IsoImage *image, const char *image_path,
     ret = create_image(image, image_path, type, &boot_img, &boot_node);
     if (ret < 0) 
         return ret;
-    if (!(boot_node->explicit_weight || boot_node->from_old_session))
+    if (boot_node != NULL)
-        boot_node->sort_weight = 2;
+        if (!(boot_node->explicit_weight || boot_node->from_old_session))
+            boot_node->sort_weight = 2;
     catalog->bootimages[catalog->num_bootimages] = boot_img;
     catalog->num_bootimages++;
     if (boot != NULL)
@@ -827,12 +858,13 @@ write_section_header(uint8_t *buf, Ecma119Image *t, int idx, int num_entries)
  * Usable for the Default Entry
  * and for Section Entries with Selection criteria type == 0
  */
-static void
+static
-write_section_entry(uint8_t *buf, Ecma119Image *t, int idx)
+int write_section_entry(uint8_t *buf, Ecma119Image *t, int idx)
 {
     struct el_torito_boot_image *img;
     struct el_torito_section_entry *se =
         (struct el_torito_section_entry*)buf;
+    int app_idx;
 
     img = t->catalog->bootimages[idx];
 
@@ -840,16 +872,37 @@ write_section_entry(uint8_t *buf, Ecma119Image *t, int idx)
     se->boot_media_type[0] = img->type;
     iso_lsb(se->load_seg, img->load_seg, 2);
     se->system_type[0] = img->partition_type;
-    iso_lsb(se->sec_count, img->load_size, 2);
+
-    iso_lsb(se->block, t->bootsrc[idx]->sections[0].block, 4);
+    if (t->boot_appended_idx[idx] >= 0) {
+        app_idx = t->boot_appended_idx[idx];
+        if (t->appended_part_size[app_idx] * 4 > 65535) {
+            if (img->platform_id == 0xef)
+                iso_lsb(se->sec_count, 0, 2);
+            else
+                iso_lsb(se->sec_count, 65535, 2);
+        } else {
+            if (t->appended_part_size[app_idx] == 0) {
+                iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
+          "Appended partition which shall serve as boot image does not exist");
+                return ISO_BOOT_IMAGE_NOT_VALID;
+            }
+            iso_lsb(se->sec_count, t->appended_part_size[app_idx] * 4, 2);
+        }
+        iso_lsb(se->block, t->appended_part_start[app_idx], 4);
+    } else {
+        iso_lsb(se->sec_count, img->load_size, 2);
+        iso_lsb(se->block, t->bootsrc[idx]->sections[0].block, 4);
+    }
+
     se->selec_criteria[0] = img->selection_crit[0];
     memcpy(se->vendor_sc, img->selection_crit + 1, 19);
+    return ISO_SUCCESS;
 }
 
 static
 int catalog_open(IsoStream *stream)
 {
-    int i, j, k, num_entries;
+    int i, j, k, num_entries, ret;
     struct catalog_stream *data;
     uint8_t *wpt;
     struct el_torito_boot_catalog *cat;
@@ -873,7 +926,9 @@ int catalog_open(IsoStream *stream)
                            boots[0]->platform_id, boots[0]->id_string);
 
     /* write default entry = first boot image */
-    write_section_entry(data->buffer + 32, data->target, 0);
+    ret = write_section_entry(data->buffer + 32, data->target, 0);
+    if (ret < 0)
+        return ret;
 
     /* IMPORTANT: The maximum number of boot images must fit into BLOCK_SIZE */
     wpt = data->buffer + 64;
@@ -894,7 +949,9 @@ int catalog_open(IsoStream *stream)
         write_section_header(wpt, data->target, i, num_entries);
         wpt += 32;
         for (j = 0; j < num_entries; j++) {
-            write_section_entry(wpt,  data->target, i);
+            ret = write_section_entry(wpt,  data->target, i);
+            if (ret < 0)
+                return ret;
             wpt += 32;
             i++;
         }
@@ -1132,6 +1189,9 @@ int patch_boot_info_table(uint8_t *buf, Ecma119Image *t,
         return iso_msg_submit(t->image->id, ISO_ISOLINUX_CANT_PATCH, 0,
             "Isolinux image too small. We won't patch it.");
     }
+    if (t->bootsrc[idx] == NULL)
+        return iso_msg_submit(t->image->id, ISO_ISOLINUX_CANT_PATCH, 0,
+            "Cannot apply ISOLINUX patching outside of ISO 9660 filesystem.");
     ret = make_boot_info_table(buf, t->opts->ms_block + (uint32_t) 16,
                                t->bootsrc[idx]->sections[0].block,
                                (uint32_t) imgsize);
@@ -1151,7 +1211,10 @@ int patch_grub2_boot_image(uint8_t *buf, Ecma119Image *t,
 
     if (imgsize < pos + 8)
         return iso_msg_submit(t->image->id, ISO_ISOLINUX_CANT_PATCH, 0,
-                     "Isolinux image too small for GRUB2. Will not patch it.");
+                     "Boot image too small for GRUB2. Will not patch it.");
+    if (t->bootsrc[idx] == NULL)
+        return iso_msg_submit(t->image->id, ISO_ISOLINUX_CANT_PATCH, 0,
+            "Cannot apply GRUB2 patching outside of ISO 9660 filesystem.");
     blk = ((uint64_t) t->bootsrc[idx]->sections[0].block) * 4 + offst;
     iso_lsb((buf + pos), blk & 0xffffffff, 4);
     iso_lsb((buf + pos + 4), blk >> 32, 4);
@@ -1174,6 +1237,10 @@ int iso_patch_eltoritos(Ecma119Image *t)
     for (idx = 0; idx < t->catalog->num_bootimages; idx++) {
         if (!(t->catalog->bootimages[idx]->isolinux_options & 0x201))
     continue;
+        if (t->bootsrc[idx] == NULL)
+            return iso_msg_submit(t->image->id, ISO_ISOLINUX_CANT_PATCH, 0,
+            "Cannot apply boot image patching outside of ISO 9660 filesystem");
+
         original = t->bootsrc[idx]->stream;
         size = (size_t) iso_stream_get_size(original);
         if (size > Libisofs_elto_max_patchablE)
@@ -1281,8 +1348,8 @@ int eltorito_writer_create(Ecma119Image *target)
 {
     int ret, idx, outsource_efi = 0;
     IsoImageWriter *writer;
-    IsoFile *bootimg;
+    IsoFile *bootimg = NULL;
-    IsoFileSrc *src;
+    IsoFileSrc *src = NULL;
 
     writer = calloc(1, sizeof(IsoImageWriter));
     if (writer == NULL) {
@@ -1315,6 +1382,19 @@ int eltorito_writer_create(Ecma119Image *target)
         if (strcmp(target->opts->efi_boot_partition, "--efi-boot-image") == 0)
             outsource_efi = 1;
     for (idx = 0; idx < target->catalog->num_bootimages; idx++) {
+        target->bootsrc[idx] = NULL;
+        if (target->catalog->bootimages[idx]->appended_idx >= 0) {
+            /* Use an appended partition as boot image rather than IsoFile */
+            target->boot_appended_idx[idx] =
+                                target->catalog->bootimages[idx]->appended_idx;
+            if (((target->system_area_options >> 2) & 0x3f) == 0 &&
+                (target->system_area_options & 3) == 1) {
+                /* ISO will not be a partition. It can span the whole image. */
+                target->pvd_size_is_total_size = 1;
+            }
+    continue;
+        }
+
         bootimg = target->catalog->bootimages[idx]->image;
         ret = iso_file_src_create(target, bootimg, &src);
         if (ret < 0) {

libisofs/eltorito.h

@@ -53,6 +53,9 @@ struct el_torito_boot_catalog {
 struct el_torito_boot_image {
     IsoFile *image;
 
+    /* Overrides .image if >= 0 : array index of appended partition */
+    int appended_idx;
+
     unsigned int bootable:1; /**< If the entry is bootable. */
     /**
      * Whether the boot image seems to contain a boot_info_table

libisofs/libisofs.h

@@ -3402,6 +3402,9 @@ int iso_image_get_pvd_times(IsoImage *image,
  *      returns an error and the image remains unmodified.
  * @param image_path
  *      The absolute path of a IsoFile to be used as default boot image.
+
+>>> or  --interval:appended_partition_$number...
+
  * @param type
  *      The boot media type. This can be one of 3 types:
  *             - Floppy emulation: Boot image file must be exactly
@@ -3443,7 +3446,10 @@ int iso_image_set_boot_image(IsoImage *image, const char *image_path,
  *      The image to which the boot image shall be added.
  *      returns an error and the image remains unmodified.
  * @param image_path
- *      The absolute path of a IsoFile to be used as default boot image.
+ *      The absolute path of a IsoFile to be used as boot image.
+
+>>> or  --interval:appended_partition_$number...
+
  * @param type
  *      The boot media type. See iso_image_set_boot_image
  * @param flag
@@ -3488,6 +3494,9 @@ int iso_image_add_boot_image(IsoImage *image, const char *image_path,
  * @param imgnode
  *      When not NULL, it will be filled with the image tree node. No extra ref
  *      is added, you can use iso_node_ref() to get one if you need it.
+
+>>> The returned value is NULL if the boot image source is no IsoFile.
+
  * @param catnode
  *      When not NULL, it will be filled with the catnode tree node. No extra
  *      ref is added, you can use iso_node_ref() to get one if you need it.
@@ -3545,6 +3554,11 @@ int iso_image_get_bootcat(IsoImage *image, IsoBoot **catnode, uint32_t *lba,
  * @param bootnodes
  *      Returns NULL or an allocated array of pointers to the IsoFile nodes
  *      which bear the content of the boot images in boots.
+
+>>> An array entry is NULL if the boot image source is no IsoFile.
+
+>>> Need getter for partition index
+
  * @param flag
  *      Bitfield for control purposes. Unused yet. Submit 0.
  * @return

libisofs/make_isohybrid_mbr.c

@@ -37,6 +37,8 @@
 #include "ecma119.h"
 #include "eltorito.h"
 #include "system_area.h"
+#include "image.h"
+#include "messages.h"
 
 
 /* This code stems from syslinux-3.72/utils/isohybrid, a perl script
@@ -60,7 +62,7 @@ license from above stem licenses, typically from LGPL.
 In case its generosity is needed, here is the 2-clause BSD license:
 
 make_isohybrid_mbr.c is copyright 2002-2008 H. Peter Anvin
-                              and 2008-2014 Thomas Schmitt
+                              and 2008-2015 Thomas Schmitt
 
 1. Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.
@@ -408,6 +410,7 @@ int assess_isohybrid_gpt_apm(Ecma119Image *t, int *gpt_count, int gpt_idx[128],
 {
     int i, ilx_opts, j, ret, num_img;
     uint32_t block_count;
+    uint64_t start_block;
     uint8_t gpt_name[72];
     static uint8_t zero_uuid[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
     static uint8_t basic_data_uuid[16] = {
@@ -430,11 +433,13 @@ int assess_isohybrid_gpt_apm(Ecma119Image *t, int *gpt_count, int gpt_idx[128],
         num_img = 0;
     for (i = 0; i < num_img; i++) {
         ilx_opts = t->catalog->bootimages[i]->isolinux_options;
-        if (((ilx_opts >> 2) & 63) == 1 || ((ilx_opts >> 2) & 63) == 2) {
+        if ((((ilx_opts >> 2) & 63) == 1 || ((ilx_opts >> 2) & 63) == 2) &&
+           !(t->boot_appended_idx[i] >= 0 && t->opts->appended_as_gpt)) {
             if (*gpt_count < 128)
                 gpt_idx[*gpt_count]= i;
             (*gpt_count)++;
-            if ((flag & 1) && t->bootsrc[i] != NULL) {
+            if ((flag & 1) &&
+                (t->bootsrc[i] != NULL || t->boot_appended_idx[i] >= 0)) {
                 /* Register GPT entry */
                 memset(gpt_name, 0, 72);
                 sprintf((char *) gpt_name, "ISOHybrid%d", *gpt_count);
@@ -443,13 +448,21 @@ int assess_isohybrid_gpt_apm(Ecma119Image *t, int *gpt_count, int gpt_idx[128],
                     uuid = hfs_uuid;
                 else
                     uuid = basic_data_uuid;
-                block_count = 0;
+                if (t->boot_appended_idx[i] >= 0) {
-                for (j = 0; j < t->bootsrc[i]->nsections; j++)
+                    block_count = t->appended_part_size[
-                     block_count += t->bootsrc[i]->sections[j].size / 2048;
+                                                      t->boot_appended_idx[i]];
+                    start_block = ((uint64_t) t->appended_part_start[
+                                                 t->boot_appended_idx[i]]) * 4;
+                } else {
+                    block_count = 0;
+                    for (j = 0; j < t->bootsrc[i]->nsections; j++)
+                        block_count += t->bootsrc[i]->sections[j].size / 2048;
+                    start_block = ((uint64_t) t->bootsrc[i]->sections[0].block)
+                                  * 4;
+                }
                 ret = iso_quick_gpt_entry(
                             t->gpt_req, &(t->gpt_req_count),
-                            ((uint64_t) t->bootsrc[i]->sections[0].block) * 4,
+                            start_block, ((uint64_t) block_count) * 4,
-                            ((uint64_t) block_count) * 4,
                             uuid, zero_uuid, gpt_flags, (uint8_t *) gpt_name);
                 if (ret < 0)
                     return ret;
@@ -457,13 +470,22 @@ int assess_isohybrid_gpt_apm(Ecma119Image *t, int *gpt_count, int gpt_idx[128],
         }
         if ((ilx_opts & 256) && !(flag & 2)) {
             (*apm_count)++;
-            if ((flag & 1) && t->bootsrc[i] != NULL) {
+            if ((flag & 1) &&
+                (t->bootsrc[i] != NULL || t->boot_appended_idx[i] >= 0)) {
                 /* Register APM entry */
-                block_count = 0;
+                if (t->boot_appended_idx[i] >= 0) {
-                for (j = 0; j < t->bootsrc[i]->nsections; j++)
+                    block_count = t->appended_part_size[
-                     block_count += t->bootsrc[i]->sections[j].size / 2048;
+                                                      t->boot_appended_idx[i]];
+                    start_block = t->appended_part_start[
+                                                      t->boot_appended_idx[i]];
+                } else {
+                    block_count = 0;
+                    for (j = 0; j < t->bootsrc[i]->nsections; j++)
+                        block_count += t->bootsrc[i]->sections[j].size / 2048;
+                    start_block = t->bootsrc[i]->sections[0].block;
+                }
                 ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
-                                          t->bootsrc[i]->sections[0].block,
+                                          (uint32_t) start_block,
                                           block_count, "EFI", "Apple_HFS");
                 if (ret < 0)
                     return ret;
@@ -546,13 +568,18 @@ static int gpt_images_as_mbr_partitions(Ecma119Image *t, char *wpt,
         0xfe, 0xff, 0xff, 
     };
 
+    if (t->bootsrc[gpt_idx[*gpt_cursor]] == NULL) {
+        (*gpt_cursor)++;
+        return 2;
+    }
+
     wpt[0] = 0;
     memcpy(wpt + 1, dummy_chs, 3);
     ilx_opts = t->catalog->bootimages[gpt_idx[*gpt_cursor]]->isolinux_options;
     if (((ilx_opts >> 2) & 63) == 2)
         wpt[4] = 0x00; /* HFS gets marked as "Empty" */
     else
-        ((unsigned char *) wpt)[4] = 0xef; /* "EFI (FAT-12/16/" */
+        ((unsigned char *) wpt)[4] = 0xef; /* "EFI (FAT-12/16)" */
 
     memcpy(wpt + 5, dummy_chs, 3);
 
@@ -589,6 +616,10 @@ int make_isolinux_mbr(uint32_t *img_blocks, Ecma119Image *t,
     struct timeval tv;
     struct timezone tz;
 
+    if (t->bootsrc[0] == NULL)
+        return iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
+      "Cannot refer by isohybrid MBR to data outside of ISO 9660 filesystem.");
+
     if (flag & 2) {
         part_number = 1;
         part_offset = 1;

libisofs/system_area.c

@@ -1820,6 +1820,9 @@ int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
         /* Check for isolinux image with magic number of 3.72 and produce
            an MBR from our built-in template. (Deprecated since 31 Mar 2010)
         */
+        if (t->bootsrc[0] == NULL)
+            return iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
+      "Cannot refer by isohybrid MBR to data outside of ISO 9660 filesystem.");
         if (img_blocks < 0x80000000) {
             int_img_blocks= img_blocks;
         } else {
@@ -2062,6 +2065,9 @@ int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
 
     if (sa_type == 0 && (t->system_area_options & 0x4000) && !do_isohybrid) {
         /* Patch MBR for GRUB2 */
+        if (t->bootsrc[0] == NULL)
+            return iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
+          "Cannot refer by GRUB2 MBR to data outside of ISO 9660 filesystem.");
         blk = t->bootsrc[0]->sections[0].block * 4 +
                                                 Libisofs_grub2_mbr_patch_offsT;
         wpt = buf + Libisofs_grub2_mbr_patch_poS;