From 9f41299ed5d19073ac6694ce96a8762ab1881583 Mon Sep 17 00:00:00 2001
From: Stephen Smalley <stephen.smalley.work@gmail.com>
Date: Thu, 4 Jun 2020 16:08:31 -0400
Subject: [PATCH] libselinux: fix selinux_restorecon() statfs bug
As reported in https://github.com/SELinuxProject/selinux/issues/248,
setfiles -r (rootpath) fails when the alternate root contains a symlink
that is correct relative to the alternate root but not in the current root.
This is a regression introduced by commit e016502c0a26 ("libselinux: Save
digest of all partial matches for directory"). Do not call statfs(2) here
if acting on a symbolic link. Unfortunately there is no lstatfs() call.
Ensure that we initialize the statfs buffer always. If the supplied
file is a symlink, then we don't need to worry about the later tests of
filesystem type because we wouldn't be setting the digest anyway and
we are not performing a full sysfs relabel. While here, fix the earlier
test for a directory to use the correct test.
Reproducer:
$ mkdir /root/my-chroot && echo foo > /root/my-chroot/link-target && ln -s /link-target /root/my-chroot/symlink
$ echo "/root/my-chroot/symlink" | setfiles -vFi -r /root/my-chroot -f - /etc/selinux/targeted/contexts/files/file_contexts
Before:
setfiles: statfs(/root/my-chroot/symlink) failed: No such file or directory
After:
Relabeled /root/my-chroot/symlink from unconfined_u:object_r:admin_home_t:s0 to system_u:object_r:default_t:s0
Fixes: https://github.com/SELinuxProject/selinux/issues/248
Fixes: e016502c0a26 ("libselinux: Save digest of all partial matches for directory")
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Tested-by: Jonathan Lebon <jlebon@redhat.com>
Acked-by: Petr Lautrbach <plautrba@redhat.com>
---
libselinux/src/selinux_restorecon.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/libselinux/src/selinux_restorecon.c b/libselinux/src/selinux_restorecon.c
index 028d8924235f..c6c9184ed190 100644
--- a/libselinux/src/selinux_restorecon.c
+++ b/libselinux/src/selinux_restorecon.c
@@ -929,7 +929,7 @@ int selinux_restorecon(const char *pathname_orig,
}
/* Skip digest if not a directory */
- if ((sb.st_mode & S_IFDIR) != S_IFDIR)
+ if (!S_ISDIR(sb.st_mode))
setrestorecondigest = false;
if (!flags.recurse) {
@@ -943,7 +943,8 @@ int selinux_restorecon(const char *pathname_orig,
}
/* Obtain fs type */
- if (statfs(pathname, &sfsb) < 0) {
+ memset(&sfsb, 0, sizeof sfsb);
+ if (!S_ISLNK(sb.st_mode) && statfs(pathname, &sfsb) < 0) {
selinux_log(SELINUX_ERROR,
"statfs(%s) failed: %s\n",
pathname, strerror(errno));
--
2.26.2