ntfs: MFT record may be changed when invoking ntfs_attr_lookup()

After invoking ntfs_attr_lookup(), the attribute type that we're looking
for may be allocated in a other MFT record, so the parameter which gets
the current MFT record can be changed once to point to the other MFT
record that actually contains the wanted attribute type.

Signed-off-by: Paulo Alcantara <pcacjr@gmail.com>

diff --git a/core/fs/ntfs/ntfs.c b/core/fs/ntfs/ntfs.c
index 9170015..a90bc4c 100644 (file)
--- a/core/fs/ntfs/ntfs.c
+++ b/core/fs/ntfs/ntfs.c
@@ -415,9 +415,9 @@ out:
     return -1;
 }
 
-static const struct ntfs_mft_record *
+static struct ntfs_mft_record *
 ntfs_attr_list_lookup(struct fs_info *fs, struct ntfs_attr_record *attr,
-                      uint32_t type, const struct ntfs_mft_record *mrec)
+                      uint32_t type, struct ntfs_mft_record *mrec)
 {
     uint8_t *attr_len;
     struct mapping_chunk chunk;
@@ -534,21 +534,22 @@ found:
 
 static struct ntfs_attr_record *
 ntfs_attr_lookup(struct fs_info *fs, uint32_t type,
-                 const struct ntfs_mft_record *mrec)
+                 struct ntfs_mft_record **mrec)
 {
+    struct ntfs_mft_record *_mrec = *mrec;
     struct ntfs_attr_record *attr;
     struct ntfs_attr_record *attr_list_attr;
 
     dprintf("in %s\n", __func__);
 
     /* sanity check */
-    if (!mrec || type == NTFS_AT_END)
+    if (!_mrec || type == NTFS_AT_END)
         goto out;
 
 again:
     attr_list_attr = NULL;
 
-    attr = (struct ntfs_attr_record *)((uint8_t *)mrec + mrec->attrs_offset);
+    attr = (struct ntfs_attr_record *)((uint8_t *)_mrec + _mrec->attrs_offset);
     /* walk through the file attribute records */
     for (;; attr = (struct ntfs_attr_record *)((uint8_t *)attr + attr->len)) {
         if (attr->type == NTFS_AT_END)
@@ -556,7 +557,7 @@ again:
 
         if (attr->type == NTFS_AT_ATTR_LIST) {
             dprintf("MFT record #%lu has an $ATTRIBUTE_LIST attribute.\n",
-                    mrec->mft_record_no);
+                    _mrec->mft_record_no);
             attr_list_attr = attr;
             continue;
         }
@@ -570,10 +571,13 @@ again:
      * it as well.
      */
     if (attr->type == NTFS_AT_END && attr_list_attr) {
-        mrec = ntfs_attr_list_lookup(fs, attr_list_attr, type, mrec);
-        if (!mrec)
+        struct ntfs_mft_record *retval;
+
+        retval = ntfs_attr_list_lookup(fs, attr_list_attr, type, _mrec);
+        if (!retval)
             goto out;
 
+        _mrec = retval;
         goto again;
     } else if (attr->type == NTFS_AT_END && !attr_list_attr) {
         attr = NULL;
@@ -622,7 +626,7 @@ static int index_inode_setup(struct fs_info *fs, unsigned long mft_no,
     d_type = get_inode_mode(mrec);
     if (d_type == DT_DIR) {    /* directory stuff */
         dprintf("Got a directory.\n");
-        attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ROOT, mrec);
+        attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ROOT, &mrec);
         if (!attr) {
             printf("No attribute found.\n");
             goto out;
@@ -654,7 +658,7 @@ static int index_inode_setup(struct fs_info *fs, unsigned long mft_no,
         readdir_state->in_idx_root = true;
     } else if (d_type == DT_REG) {        /* file stuff */
         dprintf("Got a file.\n");
-        attr = ntfs_attr_lookup(fs, NTFS_AT_DATA, mrec);
+        attr = ntfs_attr_lookup(fs, NTFS_AT_DATA, &mrec);
         if (!attr) {
             printf("No attribute found.\n");
             goto out;
@@ -744,7 +748,7 @@ static struct inode *ntfs_index_lookup(const char *dname, struct inode *dir)
         goto out;
     }
 
-    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ROOT, mrec);
+    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ROOT, &mrec);
     if (!attr) {
         printf("No attribute found.\n");
         goto out;
@@ -786,7 +790,7 @@ static struct inode *ntfs_index_lookup(const char *dname, struct inode *dir)
 
     /* then descend into child node */
 
-    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ALLOCATION, mrec);
+    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ALLOCATION, &mrec);
     if (!attr) {
         printf("No attribute found.\n");
         goto out;
@@ -987,7 +991,7 @@ static uint32_t ntfs_getfssec(struct file *file, char *buf, int sectors,
             goto out;
         }
 
-        attr = ntfs_attr_lookup(fs, NTFS_AT_DATA, mrec);
+        attr = ntfs_attr_lookup(fs, NTFS_AT_DATA, &mrec);
         if (!attr) {
             printf("No attribute found.\n");
             goto out;
@@ -1048,7 +1052,7 @@ static int ntfs_readdir(struct file *file, struct dirent *dirent)
         goto out;
     }
 
-    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ROOT, mrec);
+    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ROOT, &mrec);
     if (!attr) {
         printf("No attribute found.\n");
         goto out;
@@ -1090,7 +1094,7 @@ descend_into_child_node:
     if (!(ie->flags & INDEX_ENTRY_NODE))
         goto out;
 
-    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ALLOCATION, mrec);
+    attr = ntfs_attr_lookup(fs, NTFS_AT_INDEX_ALLOCATION, &mrec);
     if (!attr)
         goto out;
 
@@ -1241,7 +1245,7 @@ static struct inode *ntfs_iget_root(struct fs_info *fs)
     }
 
     /* Fetch the volume information attribute */
-    attr = ntfs_attr_lookup(fs, NTFS_AT_VOL_INFO, mrec);
+    attr = ntfs_attr_lookup(fs, NTFS_AT_VOL_INFO, &mrec);
     if (!attr) {
         printf("Could not find volume info attribute!\n");
         goto err_attr;