From 11e381e5aa3468aa5c2634f14706336c7824f226 Mon Sep 17 00:00:00 2001
From: Petr Lautrbach <plautrba@redhat.com>
Date: Wed, 27 Jan 2021 12:00:55 +0100
Subject: [PATCH] libsemanage: sync filesystem with sandbox

Commit 331a109f91ea ("libsemanage: fsync final files before rename")
added fsync() for policy files and improved situation when something
unexpected happens right after rename(). However the module store could
be affected as well. After the following steps module files could be 0
size:

1. Run `semanage fcontext -a -t var_t "/tmp/abc"`
2. Force shutdown the server during the command is run, or right after
   it's finished
3. Boot the system and look for empty files:
    # find /var/lib/selinux/targeted/ -type f -size 0 | wc -l
    1266

It looks like this situation can be avoided if the filesystem with the
sandbox is sync()ed before we start to rename() directories in the
store.

Signed-off-by: Petr Lautrbach <plautrba@redhat.com>
Acked-by: Nicolas Iooss <nicolas.iooss@m4x.org>
---
 libsemanage/src/semanage_store.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c
index 733df8da37c2..ae023582e907 100644
--- a/libsemanage/src/semanage_store.c
+++ b/libsemanage/src/semanage_store.c
@@ -1737,6 +1737,19 @@ static int semanage_commit_sandbox(semanage_handle_t * sh)
 	}
 	close(fd);
 
+	/* sync changes in sandbox to filesystem */
+	fd = open(sandbox, O_DIRECTORY);
+	if (fd == -1) {
+		ERR(sh, "Error while opening %s for syncfs(): %d", sandbox, errno);
+		return -1;
+	}
+	if (syncfs(fd) == -1) {
+		ERR(sh, "Error while syncing %s to filesystem: %d", sandbox, errno);
+		close(fd);
+		return -1;
+	}
+	close(fd);
+
 	retval = commit_number;
 
 	if (semanage_get_active_lock(sh) < 0) {
-- 
2.30.0