From c8100ec06fe472b656e6313db0ae66b32fc69044 Mon Sep 17 00:00:00 2001
From: Christophe Grenier <grenier@cgsecurity.org>
Date: Sat, 13 Mar 2021 16:37:53 +0100
Subject: [PATCH] src/file_vmg.c: add Frama-C annotations

---
 src/file_vmg.c | 58 +++++++++++++++++++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 19 deletions(-)

diff --git a/src/file_vmg.c b/src/file_vmg.c
index 4d17693c..544a39f1 100644
--- a/src/file_vmg.c
+++ b/src/file_vmg.c
@@ -31,43 +31,63 @@
 #include "types.h"
 #include "filegen.h"
 
+/*@ requires \valid(file_stat); */
 static void register_header_check_vmg(file_stat_t *file_stat);
 
-const file_hint_t file_hint_vmg= {
-  .extension="vmg",
-  .description="Nokia Text Message",
-  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
-  .recover=1,
-  .enable_by_default=1,
-  .register_header_check=&register_header_check_vmg
+const file_hint_t file_hint_vmg = {
+  .extension = "vmg",
+  .description = "Nokia Text Message",
+  .max_filesize = PHOTOREC_MAX_FILE_SIZE,
+  .recover = 1,
+  .enable_by_default = 1,
+  .register_header_check = &register_header_check_vmg
 };
 
+/*@
+  @ requires \valid(file_recovery);
+  @ requires valid_file_recovery(file_recovery);
+  @ requires \separated(file_recovery, file_recovery->handle, file_recovery->extension, &errno, &Frama_C_entropy_source);
+  @ requires file_recovery->file_check == &file_check_vmg;
+  @ ensures \valid(file_recovery->handle);
+  @ assigns *file_recovery->handle, errno, file_recovery->file_size;
+  @ assigns Frama_C_entropy_source;
+  @*/
 static void file_check_vmg(file_recovery_t *file_recovery)
 {
-  const unsigned char vmg_footer[0x15]= {
-    0x00, '\n', 0x00, 'E' , 0x00, 'N' , 0x00, 'D' ,
-    0x00, ':' , 0x00, 'V' , 0x00, 'M' , 0x00, 'S' ,
-    0x00, 'G' , 0x00, '\n', 0x00
+  const unsigned char vmg_footer[0x15] = {
+    0x00, '\n', 0x00, 'E', 0x00, 'N', 0x00, 'D',
+    0x00, ':', 0x00, 'V', 0x00, 'M', 0x00, 'S',
+    0x00, 'G', 0x00, '\n', 0x00
   };
   file_search_footer(file_recovery, vmg_footer, sizeof(vmg_footer), 0);
 }
 
+/*@
+  @ requires buffer_size >= 0 ;
+  @ requires \valid_read(buffer+(0..buffer_size-1));
+  @ requires valid_file_recovery(file_recovery);
+  @ requires \valid(file_recovery_new);
+  @ requires file_recovery_new->blocksize > 0;
+  @ requires separation: \separated(&file_hint_vmg, buffer+(..), file_recovery, file_recovery_new);
+  @ ensures  \result!=0 ==> valid_file_recovery(file_recovery_new);
+  @ assigns  *file_recovery_new;
+  @*/
 static int header_check_vmg(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)
 {
   reset_file_recovery(file_recovery_new);
-  file_recovery_new->extension=file_hint_vmg.extension;
-  file_recovery_new->file_check=&file_check_vmg;
+  file_recovery_new->extension = file_hint_vmg.extension;
+  file_recovery_new->file_check = &file_check_vmg;
   return 1;
 }
 
 static void register_header_check_vmg(file_stat_t *file_stat)
 {
-  static const unsigned char vmg_header[0x28]=  {
-    'B' , 0x00, 'E' , 0x00, 'G' , 0x00, 'I' , 0x00,
-    'N' , 0x00, ':' , 0x00, 'V' , 0x00, 'M' , 0x00,
-    'S' , 0x00, 'G' , 0x00, '\n', 0x00, 'V' , 0x00,
-    'E' , 0x00, 'R' , 0x00, 'S' , 0x00, 'I' , 0x00,
-    'O' , 0x00, 'N' , 0x00, ':' , 0x00, '1' , 0x00
+  static const unsigned char vmg_header[0x28] = {
+    'B', 0x00, 'E', 0x00, 'G', 0x00, 'I', 0x00,
+    'N', 0x00, ':', 0x00, 'V', 0x00, 'M', 0x00,
+    'S', 0x00, 'G', 0x00, '\n', 0x00, 'V', 0x00,
+    'E', 0x00, 'R', 0x00, 'S', 0x00, 'I', 0x00,
+    'O', 0x00, 'N', 0x00, ':', 0x00, '1', 0x00
   };
   register_header_check(0, vmg_header, sizeof(vmg_header), &header_check_vmg, file_stat);
 }