CE fix strange characters appearing at the end of file

kernel/fs/tarfs.c

@@ -25,31 +25,39 @@ static struct tar_file* tar_get_file (struct tarfs* tarfs, const char* filename)
 
 static size_t tar_get_size (uint8_t* in) {
   size_t size = 0;
-  size_t j;
-  size_t count = 1;
+  for (size_t i = 0; i < 11; i++) {
+    if (in[i] < '0' || in[i] > '7')
+      break;
 
-  for (j = 11; j > 0; j--, count *= 8)
-    size += ((in[j - 1] - '0') * count);
+    size = (size * 8) + (in[i] - '0');
+  }
 
   return size;
 }
 
-static size_t tar_parse (struct tarfs* tarfs, uint8_t* addr) {
+static size_t tar_parse (struct tarfs* tarfs, uint8_t* addr, size_t max_size) {
   size_t i;
+  uint8_t* ptr = addr;
 
   for (i = 0; i < TARFS_FILES_MAX; i++) {
-    struct tar_header* hdr = (struct tar_header*)addr;
+    struct tar_header* hdr = (struct tar_header*)ptr;
 
     if (hdr->filename[0] == '\0')
       break;
 
+    if ((size_t)(ptr - addr) + 512 > max_size)
+      break;
+
     size_t size = tar_get_size (hdr->size);
 
     tarfs->tarfs_files[i].header = hdr;
-    tarfs->tarfs_files[i].content = (uint8_t*)((uintptr_t)hdr + 512);
-    tarfs->tarfs_files[i].size = tar_get_size ((uint8_t*)hdr->size);
+    tarfs->tarfs_files[i].content = ptr + 512;
+    tarfs->tarfs_files[i].size = size;
 
-    addr += 512 + ((size + 511) & ~511);
+    ptr += 512 + ((size + 511) & ~511);
+
+    if ((size_t)(ptr - addr) > max_size)
+      break;
   }
 
   return i;
@@ -92,6 +100,7 @@ int tarfs_mount (struct vfs_volume* volume, bool format) {
   if (buffer == NULL) {
     spin_unlock (&back_device->lock);
     free (volume->udata);
+    volume->udata = NULL;
     return ret;
   }
 
@@ -105,12 +114,14 @@ int tarfs_mount (struct vfs_volume* volume, bool format) {
 
   if (ret < 0) {
     free (buffer);
+    free (volume->udata);
+    volume->udata = NULL;
     return ret;
   }
 
   tarfs->buffer = buffer;
 
-  tar_parse (tarfs, tarfs->buffer);
+  tar_parse (tarfs, tarfs->buffer, total_size);
 
   return ret;
 }
@@ -166,6 +177,9 @@ int tarfs_read_file (struct vfs_volume* volume, const char* path, uint8_t* buffe
   if (file == NULL)
     return -ST_NOT_FOUND;
 
+  if (off >= file->size)
+    return -ST_OOB_ERROR;
+
   memcpy (buffer, (void*)((uintptr_t)file->content + off), min (size, file->size));
 
   return ST_OK;
@@ -183,19 +197,21 @@ int tarfs_read_dir_entry (struct vfs_volume* volume, const char* path, struct di
 
   size_t entry_counter = 0;
   for (size_t i = 0; i < TARFS_FILES_MAX; i++) {
-    if ((tarfs->tarfs_files[i].header != NULL) && (entry_num == entry_counter)) {
-      tar_file = &tarfs->tarfs_files[i];
-      break;
+    if (tarfs->tarfs_files[i].header != NULL) {
+      if (entry_num == entry_counter) {
+        tar_file = &tarfs->tarfs_files[i];
+        break;
+      }
+      entry_counter++;
     }
-    entry_counter++;
   }
 
   if (tar_file != NULL) {
     sprintf (entry->path, "/%s", tar_file->header->filename);
-    return ST_NOT_DIR;
+    return ST_OK;
   }
 
-  return ST_DIR_NO_ENTRIES;
+  return -ST_DIR_NO_ENTRIES;
 }
 
 int tarfs_write_file (struct vfs_volume* volume, const char* path, uint8_t* buffer, size_t off,