PhotoRec: recover dovecot encrypted files (Disable by default)

3 files changed, 133 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index beb47ed1..33e30955 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -126,6 +126,7 @@ file_C			= filegen.c \
 			  file_djv.c \
 			  file_dmp.c \
 			  file_doc.c \
+			  file_dovecot.c \
 			  file_dpx.c \
 			  file_drw.c \
 			  file_drw2.c \
diff --git a/src/file_dovecot.c b/src/file_dovecot.c
new file mode 100644
index 00000000..c1f4c20c
--- /dev/null
+++ b/src/file_dovecot.c
@@ -0,0 +1,128 @@
+/*
+
+    File: file_dovecot.c
+
+    Copyright (C) 2021 Christophe GRENIER <[email protected]>
+
+    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.
+
+ */
+
+#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_dovecot)
+#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"
+
+/*@ requires valid_register_header_check(file_stat); */
+static void register_header_check_dovecot(file_stat_t *file_stat);
+
+const file_hint_t file_hint_dovecot= {
+  .extension="dovecot",
+  .description="dovecot encrypted files",
+  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
+  .recover=1,
+  .enable_by_default=0,
+  .register_header_check=&register_header_check_dovecot
+};
+
+/*@
+  @ requires file_recovery->data_check==&data_check_dovecot2;
+  @ requires valid_data_check_param(buffer, buffer_size, file_recovery);
+  @ ensures  valid_data_check_result(\result, file_recovery);
+  @ ensures \result == DC_CONTINUE || \result == DC_ERROR;
+  @ assigns file_recovery->data_check;
+  @*/
+static data_check_t data_check_dovecot2(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
+{
+  /*@
+    @ loop assigns file_recovery->data_check;
+    @*/
+  if(file_recovery->calculated_file_size + buffer_size/2  >= file_recovery->file_size &&
+      file_recovery->calculated_file_size + 2 <= file_recovery->file_size + buffer_size/2)
+  {
+    const unsigned int i=file_recovery->calculated_file_size + buffer_size/2 - file_recovery->file_size;
+    /*@ assert 0 <= i <= buffer_size - 2; */
+    if(buffer[i] == 0 && buffer[i+1] == 0)
+    {
+      return DC_ERROR;
+    }
+    file_recovery->data_check=NULL;
+  }
+  return DC_CONTINUE;
+}
+/*@
+  @ requires file_recovery->data_check==&data_check_dovecot;
+  @ requires valid_data_check_param(buffer, buffer_size, file_recovery);
+  @ ensures  valid_data_check_result(\result, file_recovery);
+  @ ensures \result == DC_CONTINUE || \result == DC_ERROR;
+  @ assigns file_recovery->calculated_file_size, file_recovery->data_check;
+  @*/
+static data_check_t data_check_dovecot(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
+{
+  unsigned int i;
+  /*@
+    @ loop assigns i;
+    @*/
+  for(i=buffer_size/2;
+      i<buffer_size && file_recovery->calculated_file_size+i <= 0x14000;
+      i++)
+  {
+    if(buffer[i]!='\0')
+      return DC_ERROR;
+  }
+  if(file_recovery->calculated_file_size+buffer_size/2 < 0x14000)
+  {
+    file_recovery->calculated_file_size+=buffer_size/2;
+    return DC_CONTINUE;
+  }
+  file_recovery->calculated_file_size=0x14000;
+  file_recovery->data_check=data_check_dovecot2;
+  return data_check_dovecot2(buffer, buffer_size, file_recovery);
+}
+
+/*@
+  @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
+  @ ensures  valid_header_check_result(\result, file_recovery_new);
+  @*/
+static int header_check_dovecot(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)
+{
+  if(file_recovery->data_check==&data_check_dovecot)
+    return 0;
+  reset_file_recovery(file_recovery_new);
+  file_recovery_new->extension=file_hint_dovecot.extension;
+  file_recovery_new->data_check=&data_check_dovecot;
+  file_recovery_new->min_filesize=0x14000;
+  return 1;
+}
+
+static void register_header_check_dovecot(file_stat_t *file_stat)
+{
+  static const unsigned char dovecot_header[0x30]=  {
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0
+  };
+  register_header_check(0, dovecot_header, sizeof(dovecot_header), &header_check_dovecot, file_stat);
+}
+#endif
diff --git a/src/file_list.c b/src/file_list.c
index 0e0ea878..a5806fc2 100644
--- a/src/file_list.c
+++ b/src/file_list.c
@@ -104,6 +104,7 @@ extern const file_hint_t file_hint_dir;
 extern const file_hint_t file_hint_djv;
 extern const file_hint_t file_hint_dmp;
 extern const file_hint_t file_hint_doc;
+extern const file_hint_t file_hint_dovecot;
 extern const file_hint_t file_hint_dpx;
 extern const file_hint_t file_hint_drw;
 extern const file_hint_t file_hint_drw2;
@@ -610,6 +611,9 @@ file_enable_t array_file_enable[]=
 #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_doc)
   { .enable=0, .file_hint=&file_hint_doc  },
 #endif
+#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_dovecot)
+  { .enable=0, .file_hint=&file_hint_dovecot },
+#endif
 #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_dpx)
   { .enable=0, .file_hint=&file_hint_dpx  },
 #endif