[PATCH] debugfs: fix security_locked_down() call for SELinux
From: Ondrej Mosnacek <hidden>
Date: 2021-05-07 11:42:03
Also in:
linux-fsdevel, lkml, selinux
Subsystem:
driver core, kobjects, debugfs and sysfs, filesystems (vfs and infrastructure), the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Alexander Viro, Christian Brauner, Linus Torvalds
Make sure that security_locked_down() is checked last so that a bogus
denial is not reported by SELinux when (ia->ia_valid & (ATTR_MODE |
ATTR_UID | ATTR_GID)) is zero.
Note: this was introduced by commit 5496197f9b08 ("debugfs: Restrict
debugfs when the kernel is locked down"), but it didn't matter at that
time, as the SELinux support came in later.
Fixes: 59438b46471a ("security,lockdown,selinux: implement SELinux lockdown")
Signed-off-by: Ondrej Mosnacek <redacted>
---
fs/debugfs/inode.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 22e86ae4dd5a..bbfc7898c1aa 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c@@ -45,10 +45,13 @@ static unsigned int debugfs_allow = DEFAULT_DEBUGFS_ALLOW_BITS; static int debugfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, struct iattr *ia) { - int ret = security_locked_down(LOCKDOWN_DEBUGFS); + int ret; - if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) - return ret; + if (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) { + ret = security_locked_down(LOCKDOWN_DEBUGFS); + if (ret) + return ret; + } return simple_setattr(&init_user_ns, dentry, ia); }
--
2.31.1