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Commit 0e082555 authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
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ovl: check for bad and whiteout index on lookup 



Index should always be of the same file type as origin, except for
the case of a whiteout index.  A whiteout index should only exist
if all lower aliases have been unlinked, which means that finding
a lower origin on lookup whose index is a whiteout should be treated
as a lookup error.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 61b67471

fs/overlayfs/namei.c

+17 −5
Original line number Diff line number Diff line
@@ -513,6 +513,7 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry, 
		goto out;

	}



	inode = d_inode(index);

	if (d_is_negative(index)) {

		if (upper && d_inode(origin)->i_nlink > 1) {

			pr_warn_ratelimited("overlayfs: hard link with origin but no index (ino=%lu).\n",
@@ -522,11 +523,22 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry, 


		dput(index);

		index = NULL;

	} else if (upper && d_inode(index) != d_inode(upper)) {

		inode = d_inode(index);

		pr_warn_ratelimited("overlayfs: wrong index found (index ino: %lu, upper ino: %lu).\n",

				    d_inode(index)->i_ino,

				    d_inode(upper)->i_ino);

	} else if (upper && d_inode(upper) != inode) {

		pr_warn_ratelimited("overlayfs: wrong index found (index=%pd2, ino=%lu, upper ino=%lu).\n",

				    index, inode->i_ino, d_inode(upper)->i_ino);

		goto fail;

	} else if (ovl_dentry_weird(index) || ovl_is_whiteout(index) ||

		   ((inode->i_mode ^ d_inode(origin)->i_mode) & S_IFMT)) {

		/*

		 * Index should always be of the same file type as origin

		 * except for the case of a whiteout index. A whiteout

		 * index should only exist if all lower aliases have been

		 * unlinked, which means that finding a lower origin on lookup

		 * whose index is a whiteout should be treated as an error.

		 */

		pr_warn_ratelimited("overlayfs: bad index found (index=%pd2, ftype=%x, origin ftype=%x).\n",

				    index, d_inode(index)->i_mode & S_IFMT,

				    d_inode(origin)->i_mode & S_IFMT);

		goto fail;

	}