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| author | Ondrej Mosnacek <omosnace@redhat.com> | 2021-05-07 14:53:04 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-18 18:05:59 +0200 |
| commit | 5881fa8dc2de9697a89451f6518e8b3a796c09c6 (patch) | |
| tree | eccf4c734a67417eaad33fea91bd2750bce801b3 /fs/debugfs | |
| parent | Linux 5.13-rc2 (diff) | |
| download | linux-5881fa8dc2de9697a89451f6518e8b3a796c09c6.tar.xz linux-5881fa8dc2de9697a89451f6518e8b3a796c09c6.zip | |
debugfs: fix security_locked_down() call for SELinux
When (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) is zero, then
the SELinux implementation of the locked_down hook might report a denial
even though the operation would actually be allowed.
To fix this, make sure that security_locked_down() is called only when
the return value will be taken into account (i.e. when changing one of
the problematic attributes).
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")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Link: https://lore.kernel.org/r/20210507125304.144394-1-omosnace@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/debugfs')
| -rw-r--r-- | fs/debugfs/inode.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 1d252164d97b..8129a430d789 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -45,10 +45,13 @@ static unsigned int debugfs_allow __ro_after_init = 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); } |