linux-ext4 - [PATCH] create_inode: set xattrs to the root directory as well

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Date:   Wed,  1 Jul 2020 17:34:04 +0200
From:   Antoine Tenart <antoine.tenart@...tlin.com>
To:     linux-ext4@...r.kernel.org, tytso@....edu
Cc:     Antoine Tenart <antoine.tenart@...tlin.com>,
        matthew.weber@...kwellcollins.com, thomas.petazzoni@...tlin.com
Subject: [PATCH] create_inode: set xattrs to the root directory as well

__populate_fs do copy the xattrs for all files and directories, but the
root directory is skipped and as a result its extended attributes aren't
set. This is an issue when using mkfs to build a full system image that
can be used with SElinux in enforcing mode without making any runtime
fix at first boot.

This patch adds logic to set the root directory's extended attributes.

Signed-off-by: Antoine Tenart <antoine.tenart@...tlin.com>
---
 misc/create_inode.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/misc/create_inode.c b/misc/create_inode.c
index e8d1df6b55a5..0a6e4dc23d16 100644
--- a/misc/create_inode.c
+++ b/misc/create_inode.c
@@ -820,7 +820,29 @@ static errcode_t __populate_fs(ext2_filsys fs, ext2_ino_t parent_ino,
 
 	for (i = 0; i < num_dents; free(dent[i]), i++) {
 		name = dent[i]->d_name;
-		if ((!strcmp(name, ".")) || (!strcmp(name, "..")))
+		if (!strcmp(name, ".")) {
+			retval = ext2fs_namei(fs, root, parent_ino, ".", &ino);
+			if (retval) {
+				com_err(name, retval, 0);
+					goto out;
+			}
+
+			/*
+			 * Take special care for the root directory, to copy its
+			 * extended attributes.
+			 */
+			if (ino == root) {
+				retval = set_inode_xattr(fs, ino, ".");
+				if (retval) {
+					com_err(__func__, retval,
+						_("while setting xattrs for ."));
+					goto out;
+				}
+			}
+
+			continue;
+		}
+		if (!strcmp(name, ".."))
 			continue;
 		if (lstat(name, &st)) {
 			retval = errno;
-- 
2.26.2