Read/write reserved/unknown fields in WIM dentry and ADS entries

diff --git a/src/dentry.c b/src/dentry.c
index fac2be7abcaa6f72a7493ce5dd16c51dafd7219d..698e137c10dab4f90d0f744111e56d6629f28cde 100644 (file)
--- a/src/dentry.c
+++ b/src/dentry.c
@@ -1258,6 +1258,11 @@ inode_set_unix_data(struct wim_inode *inode, uid_t uid, gid_t gid, mode_t mode,
 }
 #endif /* !__WIN32__ */
 
+/* Replace weird characters in filenames and alternate data stream names.
+ *
+ * In particular we do not want the path separator to appear in any names, as
+ * that would make it possible for a "malicious" WIM to extract itself to any
+ * location it wanted to. */
 static void
 replace_forbidden_characters(utf16lechar *name)
 {
@@ -1359,7 +1364,7 @@ read_ads_entries(const u8 *p, struct wim_inode *inode, u64 remaining_size)
                }
 
                p = get_u64(p, &length);
-               p += 8; /* Skip the reserved field */
+               p = get_u64(p, &cur_entry->unused);
                p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
                p = get_u16(p, &cur_entry->stream_name_nbytes);
 
@@ -1516,10 +1521,8 @@ read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
        p = get_u32(p, (u32*)&inode->i_security_id);
        p = get_u64(p, &dentry->subdir_offset);
 
-       /* 2 unused fields */
-       p += 2 * sizeof(u64);
-       /*p = get_u64(p, &dentry->unused1);*/
-       /*p = get_u64(p, &dentry->unused2);*/
+       p = get_u64(p, &inode->i_unused_1);
+       p = get_u64(p, &inode->i_unused_2);
 
        p = get_u64(p, &inode->i_creation_time);
        p = get_u64(p, &inode->i_last_access_time);
@@ -1797,21 +1800,21 @@ write_dentry(const struct wim_dentry *dentry, u8 *p)
        p = put_u32(p, inode->i_attributes);
        p = put_u32(p, inode->i_security_id);
        p = put_u64(p, dentry->subdir_offset);
-       p = put_u64(p, 0); /* unused1 */
-       p = put_u64(p, 0); /* unused2 */
+       p = put_u64(p, inode->i_unused_1);
+       p = put_u64(p, inode->i_unused_2);
        p = put_u64(p, inode->i_creation_time);
        p = put_u64(p, inode->i_last_access_time);
        p = put_u64(p, inode->i_last_write_time);
        hash = inode_stream_hash(inode, 0);
        p = put_bytes(p, SHA1_HASH_SIZE, hash);
        if (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
-               p = put_u32(p, 0);
+               p = put_u32(p, inode->i_rp_unknown_1);
                p = put_u32(p, inode->i_reparse_tag);
-               p = put_u16(p, 0);
+               p = put_u16(p, inode->i_rp_unknown_2);
                p = put_u16(p, inode->i_not_rpfixed);
        } else {
                u64 link_group_id;
-               p = put_u32(p, 0);
+               p = put_u32(p, inode->i_rp_unknown_1);
                if (inode->i_nlink == 1)
                        link_group_id = 0;
                else
@@ -1839,7 +1842,7 @@ write_dentry(const struct wim_dentry *dentry, u8 *p)
         * alternate data stream entries. */
        for (u16 i = 0; i < inode->i_num_ads; i++) {
                p = put_u64(p, ads_entry_total_length(&inode->i_ads_entries[i]));
-               p = put_u64(p, 0); /* Unused */
+               p = put_u64(p, inode->i_ads_entries[i].unused);
                hash = inode_stream_hash(inode, i + 1);
                p = put_bytes(p, SHA1_HASH_SIZE, hash);
                p = put_u16(p, inode->i_ads_entries[i].stream_name_nbytes);

diff --git a/src/dentry.h b/src/dentry.h
index 420557ceabb6c109dd7b7e41250b3b4fac16d86b..1629111d83d1ccc5d662436aef09e7f0a2d00e98 100644 (file)
--- a/src/dentry.h
+++ b/src/dentry.h
@@ -78,12 +78,16 @@ struct wim_ads_entry {
         * terminating null character. */
        u16 stream_name_nbytes;
 
-       /* Stream name (UTF-16LE) */
-       utf16lechar *stream_name;
-
        /* Number to identify an alternate data stream even after it's possibly
         * been moved or renamed. */
        u32 stream_id;
+
+       /* Stream name (UTF-16LE) */
+       utf16lechar *stream_name;
+
+       /* Unused field.  We read it into memory so we can write it out
+        * unchanged. */
+       u64 unused;
 };
 
 
@@ -231,13 +235,20 @@ struct wim_inode {
        /* Used only in NTFS-mode extraction */
        u8 i_dos_name_extracted : 1;
 
+       /* Set to 0 if reparse point fixups have been done.  Otherwise set to 1.
+        *
+        * Note: this actually may reflect the SYMBOLIC_LINK_RELATIVE flag.  */
        u16 i_not_rpfixed;
 
        /* Number of alternate data streams associated with this inode */
        u16 i_num_ads;
 
-       u16 i_rp_unknown_2;
+       /* Unused/unknown fields that we just read into memory so we can
+        * re-write them unchanged.  */
+       u64 i_unused_1;
+       u64 i_unused_2;
        u32 i_rp_unknown_1;
+       u16 i_rp_unknown_2;
 
        /* A hash of the file's contents, or a pointer to the lookup table entry
         * for this dentry if the lookup table entries have been resolved.