exif-mnote-data-fuji.c

Go to the documentation of this file.

/* exif-mnote-data-fuji.c
 *
 * Copyright (c) 2002 Lutz Mueller <lutz@users.sourceforge.net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details. 
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301  USA.
 *
 * SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
#include <stdlib.h>
#include <string.h>
 
 
#include <config.h>
#include <libexif/exif-byte-order.h>
#include <libexif/exif-utils.h>
 
#include "exif-mnote-data-fuji.h"
 
#define CHECKOVERFLOW(offset,datasize,structsize) (( (offset) >= (datasize)) || ((structsize) > (datasize)) || ((offset) > (datasize) - (structsize) ))
 
struct _MNoteFujiDataPrivate {
        ExifByteOrder order;
};
 
static void
exif_mnote_data_fuji_clear (ExifMnoteDataFuji *n)
{
        ExifMnoteData *d = (ExifMnoteData *) n;
        unsigned int i;
 
        if (!n) return;
 
        if (n->entries) {
                for (i = 0; i < n->count; i++)
                        if (n->entries[i].data) {
                                exif_mem_free (d->mem, n->entries[i].data);
                                n->entries[i].data = NULL;
                        }
                exif_mem_free (d->mem, n->entries);
                n->entries = NULL;
                n->count = 0;
        }
}
 
static void
exif_mnote_data_fuji_free (ExifMnoteData *n)
{
        if (!n) return;
 
        exif_mnote_data_fuji_clear ((ExifMnoteDataFuji *) n);
}
 
static char *
exif_mnote_data_fuji_get_value (ExifMnoteData *d, unsigned int i, char *val, unsigned int maxlen)
{
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji *) d;
 
        if (!d || !val) return NULL;
        if (i >= n->count) return NULL;
/*
        exif_log (d->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataFuji",
                  "Querying value for tag '%s'...",
                  mnote_fuji_tag_get_name (n->entries[i].tag));
*/
        return mnote_fuji_entry_get_value (&n->entries[i], val, maxlen);
}
 
static void
exif_mnote_data_fuji_save (ExifMnoteData *ne, unsigned char **buf,
                           unsigned int *buf_size)
{
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji *) ne;
        size_t i, o, s, doff;
        unsigned char *t;
        size_t ts;
 
        if (!n || !buf || !buf_size) return;
 
        /*
         * Allocate enough memory for all entries and the number
         * of entries.
         */
        *buf_size = 8 + 4 + 2 + n->count * 12 + 4;
        *buf = exif_mem_alloc (ne->mem, *buf_size);
        if (!*buf) {
                *buf_size = 0;
                return;
        }
 
        /*
         * Header: "FUJIFILM" and 4 bytes offset to the first entry.
         * As the first entry will start right thereafter, the offset is 12.
         */
        memcpy (*buf, "FUJIFILM", 8);
        exif_set_long (*buf + 8, n->order, 12);
 
        /* Save the number of entries */
        exif_set_short (*buf + 8 + 4, n->order, (ExifShort) n->count);
        
        /* Save each entry */
        for (i = 0; i < n->count; i++) {
                o = 8 + 4 + 2 + i * 12;
                exif_set_short (*buf + o + 0, n->order, (ExifShort) n->entries[i].tag);
                exif_set_short (*buf + o + 2, n->order, (ExifShort) n->entries[i].format);
                exif_set_long  (*buf + o + 4, n->order, n->entries[i].components);
                o += 8;
                s = exif_format_get_size (n->entries[i].format) *
                                                n->entries[i].components;
                if (s > 65536) {
                        /* Corrupt data: EXIF data size is limited to the
                         * maximum size of a JPEG segment (64 kb).
                         */
                        continue;
                }
                if (s > 4) {
                        ts = *buf_size + s;
 
                        /* Ensure even offsets. Set padding bytes to 0. */
                        if (s & 1) ts += 1;
                        t = exif_mem_realloc (ne->mem, *buf, ts);
                        if (!t) {
                                return;
                        }
                        *buf = t;
                        *buf_size = ts;
                        doff = *buf_size - s;
                        if (s & 1) { doff--; *(*buf + *buf_size - 1) = '\0'; }
                        exif_set_long (*buf + o, n->order, doff);
                } else
                        doff = o;
 
                /*
                 * Write the data. Fill unneeded bytes with 0. Do not
                 * crash if data is NULL.
                 */
                if (!n->entries[i].data) memset (*buf + doff, 0, s);
                else memcpy (*buf + doff, n->entries[i].data, s);
        }
}
 
static void
exif_mnote_data_fuji_load (ExifMnoteData *en,
        const unsigned char *buf, unsigned int buf_size)
{
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji*) en;
        ExifLong c;
        size_t i, tcount, o, datao;
 
        if (!n) return;
 
        if (!buf || !buf_size) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                          "ExifMnoteDataFuji", "Short MakerNote");
                return;
        }
        if (CHECKOVERFLOW(n->offset, buf_size, 6+8+4)) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                          "ExifMnoteDataFuji", "Short MakerNote");
                return;
        }
        datao = 6 + n->offset;
 
        n->order = EXIF_BYTE_ORDER_INTEL;
 
        datao += exif_get_long (buf + datao + 8, EXIF_BYTE_ORDER_INTEL);
        if (CHECKOVERFLOW(datao, buf_size, 2)) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                          "ExifMnoteDataFuji", "Short MakerNote");
                return;
        }
 
        /* Read the number of tags */
        c = exif_get_short (buf + datao, EXIF_BYTE_ORDER_INTEL);
        datao += 2;
 
        /* Just use an arbitrary max tag limit here to avoid needing to much memory or time. There are 50 named tags currently.
         * Fuji XT2 had 56 entries or so, GFX500 has 68. 150 seems a safe upper bound currently.
         * The format allows specifying the same range of memory as often as it can, so this multiplies quickly. */
        if (c > 150) {
                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifMnoteDataFuji", "Too much tags (%d) in Fuji MakerNote", c);
                return;
        }
 
        /* Remove any old entries */
        exif_mnote_data_fuji_clear (n);
 
        /* Reserve enough space for all the possible MakerNote tags */
        n->entries = exif_mem_alloc (en->mem, sizeof (MnoteFujiEntry) * c);
        if (!n->entries) {
                EXIF_LOG_NO_MEMORY(en->log, "ExifMnoteDataFuji", sizeof (MnoteFujiEntry) * c);
                return;
        }
 
        /* Parse all c entries, storing ones that are successfully parsed */
        tcount = 0;
        for (i = c, o = datao; i; --i, o += 12) {
                size_t s;
 
                memset(&n->entries[tcount], 0, sizeof(MnoteFujiEntry));
                if (CHECKOVERFLOW(o, buf_size, 12)) {
                        exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                                  "ExifMnoteDataFuji", "Short MakerNote");
                        break;
                }
 
                n->entries[tcount].tag        = exif_get_short (buf + o, n->order);
                n->entries[tcount].format     = exif_get_short (buf + o + 2, n->order);
                n->entries[tcount].components = exif_get_long (buf + o + 4, n->order);
                n->entries[tcount].order      = n->order;
 
                exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataFuji",
                          "Loading entry 0x%x ('%s')...", n->entries[tcount].tag,
                          mnote_fuji_tag_get_name (n->entries[tcount].tag));
 
                /* Check if we overflow the multiplication. Use buf_size as the max size for integer overflow detection,
                 * we will check the buffer sizes closer later. */
                if (    exif_format_get_size (n->entries[tcount].format) &&
                        buf_size / exif_format_get_size (n->entries[tcount].format) < n->entries[tcount].components
                ) {
                        exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                                          "ExifMnoteDataFuji", "Tag size overflow detected (%u * %lu)", exif_format_get_size (n->entries[tcount].format), n->entries[tcount].components);
                        continue;
                }
                /*
                 * Size? If bigger than 4 bytes, the actual data is not
                 * in the entry but somewhere else (offset).
                 */
                s = exif_format_get_size (n->entries[tcount].format) * n->entries[tcount].components;
                n->entries[tcount].size = s;
                if (s) {
                        size_t dataofs = o + 8;
                        if (s > 4)
                                /* The data in this case is merely a pointer */
                                dataofs = exif_get_long (buf + dataofs, n->order) + 6 + n->offset;
 
                        if (CHECKOVERFLOW(dataofs, buf_size, s)) {
                                exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
                                                  "ExifMnoteDataFuji", "Tag data past end of "
                                          "buffer (%u >= %u)", (unsigned)(dataofs + s), buf_size);
                                continue;
                        }
 
                        n->entries[tcount].data = exif_mem_alloc (en->mem, s);
                        if (!n->entries[tcount].data) {
                                EXIF_LOG_NO_MEMORY(en->log, "ExifMnoteDataFuji", s);
                                continue;
                        }
                        memcpy (n->entries[tcount].data, buf + dataofs, s);
                }
 
                /* Tag was successfully parsed */
                ++tcount;
        }
        /* Store the count of successfully parsed tags */
        n->count = tcount;
}
 
static unsigned int
exif_mnote_data_fuji_count (ExifMnoteData *n)
{
        return n ? ((ExifMnoteDataFuji *) n)->count : 0;
}
 
static unsigned int
exif_mnote_data_fuji_get_id (ExifMnoteData *d, unsigned int n)
{
        ExifMnoteDataFuji *note = (ExifMnoteDataFuji *) d;
 
        if (!note) return 0;
        if (note->count <= n) return 0;
        return note->entries[n].tag;
}
 
static const char *
exif_mnote_data_fuji_get_name (ExifMnoteData *d, unsigned int i)
{
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji *) d;
 
        if (!n) return NULL;
        if (i >= n->count) return NULL;
        return mnote_fuji_tag_get_name (n->entries[i].tag);
}
 
static const char *
exif_mnote_data_fuji_get_title (ExifMnoteData *d, unsigned int i)
{
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji *) d;
        
        if (!n) return NULL;
        if (i >= n->count) return NULL;
        return mnote_fuji_tag_get_title (n->entries[i].tag);
}
 
static const char *
exif_mnote_data_fuji_get_description (ExifMnoteData *d, unsigned int i)
{
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji *) d;
        
        if (!n) return NULL;
        if (i >= n->count) return NULL;
        return mnote_fuji_tag_get_description (n->entries[i].tag);
}
 
static void
exif_mnote_data_fuji_set_byte_order (ExifMnoteData *d, ExifByteOrder o)
{
        ExifByteOrder o_orig;
        ExifMnoteDataFuji *n = (ExifMnoteDataFuji *) d;
        unsigned int i;
 
        if (!n) return;
 
        o_orig = n->order;
        n->order = o;
        for (i = 0; i < n->count; i++) {
                if (n->entries[i].components && (n->entries[i].size/n->entries[i].components < exif_format_get_size (n->entries[i].format)))
                        continue;
                n->entries[i].order = o;
                exif_array_set_byte_order (n->entries[i].format, n->entries[i].data,
                                n->entries[i].components, o_orig, o);
        }
}
 
static void
exif_mnote_data_fuji_set_offset (ExifMnoteData *n, unsigned int o)
{
        if (n) ((ExifMnoteDataFuji *) n)->offset = o;
}
 
int
exif_mnote_data_fuji_identify (const ExifData *ed, const ExifEntry *e)
{
        (void) ed;  /* unused */
        return ((e->size >= 12) && !memcmp (e->data, "FUJIFILM", 8));
}
 
ExifMnoteData *
exif_mnote_data_fuji_new (ExifMem *mem)
{
        ExifMnoteData *d;
 
        if (!mem) return NULL;
 
        d = exif_mem_alloc (mem, sizeof (ExifMnoteDataFuji));
        if (!d) return NULL;
 
        exif_mnote_data_construct (d, mem);
 
        /* Set up function pointers */
        d->methods.free            = exif_mnote_data_fuji_free;
        d->methods.set_byte_order  = exif_mnote_data_fuji_set_byte_order;
        d->methods.set_offset      = exif_mnote_data_fuji_set_offset;
        d->methods.load            = exif_mnote_data_fuji_load;
        d->methods.save            = exif_mnote_data_fuji_save;
        d->methods.count           = exif_mnote_data_fuji_count;
        d->methods.get_id          = exif_mnote_data_fuji_get_id;
        d->methods.get_name        = exif_mnote_data_fuji_get_name;
        d->methods.get_title       = exif_mnote_data_fuji_get_title;
        d->methods.get_description = exif_mnote_data_fuji_get_description;
        d->methods.get_value       = exif_mnote_data_fuji_get_value;
 
        return d;
}