[PATCH] Correction to check_filetype()

[Kalpak Shah <kalpak-KYPl3Ael/zSakBO8gow8eQ@public.gmane.org>]

Hi,

If the mode of a directory gets corrupted, check_filetype() makes wrong decisions for all its sub-directories. For example, using debugfs we can corrupt the mode of a directory to 0140755 (i.e. a socket). e2fsck will set the filetype of all its subdirectories as 6 (filetype for socket). All the subdirectories would be moved to lost+found, and in second run of e2fsck their filetype would be set back to 2.

By the time we come to check_filetype(), we have already verified the "." and ".." entries, so we special case these dirents in check_filetype().

Please consider for review.

Signed-off-by: Andreas Dilger <adilger-KYPl3Ael/zSakBO8gow8eQ@public.gmane.org>
Signed-off-by: Kalpak Shah <kalpak-KYPl3Ael/zSakBO8gow8eQ@public.gmane.org>


Index: e2fsprogs-1.39/e2fsck/pass2.c
===================================================================
--- e2fsprogs-1.39.orig/e2fsck/pass2.c
+++ e2fsprogs-1.39/e2fsck/pass2.c
@@ -495,7 +495,9 @@ static _INLINE_ int check_filetype(e2fsc
                return 1;
        }

-       if (ext2fs_test_inode_bitmap(ctx->inode_dir_map, dirent->inode)) {
+       if (ext2fs_test_inode_bitmap(ctx->inode_dir_map, dirent->inode) ||
+           ((dirent->name_len && 0xFF) <= 2 && dirent->name[0] == '.' &&
+            (dirent->name[1] == '.' || dirent->name[1] == '\0'))) {
                should_be = EXT2_FT_DIR;
        } else if (ext2fs_test_inode_bitmap(ctx->inode_reg_map,
                                            dirent->inode)) {