PhotoRec: recover .gsm files (prone to false positive)

src/Makefile.am

@@ -139,6 +139,7 @@ file_C			= filegen.c \
 			  file_gm6.c \
 			  file_gp5.c \
 			  file_gpg.c \
+			  file_gsm.c \
 			  file_gz.c \
 			  file_hdf.c \
 			  file_hds.c \

src/file_gsm.c

@@ -0,0 +1,129 @@
+/*
+
+    File: file_gsm.c
+
+    Copyright (C) 2014 Christophe GRENIER <grenier@cgsecurity.org>
+  
+    This software is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+  
+    This program 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 General Public License for more details.
+  
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write the Free Software Foundation, Inc., 51
+    Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#include <stdio.h>
+#include "types.h"
+#include "filegen.h"
+#include "common.h"
+#include "log.h"
+#include "memmem.h"
+
+static void register_header_check_gsm(file_stat_t *file_stat);
+
+const file_hint_t file_hint_gsm= {
+  .extension="gsm",
+  .description="Group Speciale Mobile GSM 06.10",
+  .min_header_distance=0,
+  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
+  .recover=1,
+  .enable_by_default=0,
+  .register_header_check=&register_header_check_gsm
+};
+
+struct block_header
+{
+  unsigned char marker;
+  unsigned char payload[32];
+} __attribute__ ((__packed__));
+
+static data_check_t data_check_gsm(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
+{
+  while(file_recovery->calculated_file_size + buffer_size/2  >= file_recovery->file_size &&
+      file_recovery->calculated_file_size + sizeof(struct block_header) < file_recovery->file_size + buffer_size/2)
+  {
+    const unsigned int i=file_recovery->calculated_file_size - file_recovery->file_size + buffer_size/2;
+    const struct block_header *hdr=(const struct block_header *)&buffer[i];
+    if(hdr->marker < 0xd0 || hdr->marker > 0xdf)
+      return DC_STOP;
+    file_recovery->calculated_file_size+=sizeof(struct block_header); 
+  }
+  return DC_CONTINUE;
+}
+
+static int header_check_gsm(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
+{
+  const struct block_header *hdr;
+  unsigned int i=0;
+  if(file_recovery->file_stat!=NULL
+      &&  file_recovery->file_stat->file_hint==&file_hint_gsm)
+    return 0;
+  for(i=0, hdr=(const struct block_header *)buffer;
+      i * sizeof(struct block_header) < file_recovery_new->blocksize;
+      i++, hdr++)
+  {
+    if(hdr->marker < 0xd0 || hdr->marker > 0xdf)
+      return 0;
+  }
+  if(i<3)
+    return 0;
+ 
+  reset_file_recovery(file_recovery_new);
+  file_recovery_new->extension=file_hint_gsm.extension;
+  file_recovery_new->min_filesize=sizeof(struct block_header);
+  file_recovery_new->calculated_file_size=0;
+  file_recovery_new->data_check=&data_check_gsm;
+  file_recovery_new->file_check=&file_check_size;
+  return 1;
+}
+
+static void register_header_check_gsm(file_stat_t *file_stat)
+{
+  static const unsigned char gsm_header1[1]={ 0xd0 };
+  static const unsigned char gsm_header2[1]={ 0xd1 };
+  static const unsigned char gsm_header3[1]={ 0xd2 };
+  static const unsigned char gsm_header4[1]={ 0xd3 };
+  static const unsigned char gsm_header5[1]={ 0xd4 };
+  static const unsigned char gsm_header6[1]={ 0xd5 };
+  static const unsigned char gsm_header7[1]={ 0xd6 };
+  static const unsigned char gsm_header8[1]={ 0xd7 };
+  static const unsigned char gsm_header9[1]={ 0xd8 };
+  static const unsigned char gsm_header10[1]={ 0xd9 };
+  static const unsigned char gsm_header11[1]={ 0xda };
+  static const unsigned char gsm_header12[1]={ 0xdb };
+  static const unsigned char gsm_header13[1]={ 0xdc };
+  static const unsigned char gsm_header14[1]={ 0xdd };
+  static const unsigned char gsm_header15[1]={ 0xde };
+  static const unsigned char gsm_header16[1]={ 0xdf };
+
+  register_header_check(0, gsm_header1, sizeof(gsm_header1), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header2, sizeof(gsm_header2), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header3, sizeof(gsm_header3), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header4, sizeof(gsm_header4), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header5, sizeof(gsm_header5), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header6, sizeof(gsm_header6), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header7, sizeof(gsm_header7), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header8, sizeof(gsm_header8), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header9, sizeof(gsm_header9), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header10, sizeof(gsm_header10), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header11, sizeof(gsm_header11), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header12, sizeof(gsm_header12), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header13, sizeof(gsm_header13), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header14, sizeof(gsm_header14), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header15, sizeof(gsm_header15), &header_check_gsm, file_stat);
+  register_header_check(0, gsm_header16, sizeof(gsm_header16), &header_check_gsm, file_stat);
+}

src/file_list.c

@@ -141,6 +141,7 @@ extern const file_hint_t file_hint_gif;
 extern const file_hint_t file_hint_gm6;
 extern const file_hint_t file_hint_gp5;
 extern const file_hint_t file_hint_gpg;
+extern const file_hint_t file_hint_gsm;
 extern const file_hint_t file_hint_gz;
 extern const file_hint_t file_hint_hdf;
 extern const file_hint_t file_hint_hds;
@@ -421,6 +422,7 @@ file_enable_t list_file_enable[]=
   { .enable=0, .file_hint=&file_hint_gm6  },
   { .enable=0, .file_hint=&file_hint_gp5  },
   { .enable=0, .file_hint=&file_hint_gpg  },
+  { .enable=0, .file_hint=&file_hint_gsm  },
   { .enable=0, .file_hint=&file_hint_gz   },
   { .enable=0, .file_hint=&file_hint_hdf  },
   { .enable=0, .file_hint=&file_hint_hds  },