From af9e57baf5210fe0263f41bfa20394ecb355be67 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 5 Mar 2019 16:17:58 -0500 Subject: [PATCH] security/selinux: fix SECURITY_LSM_NATIVE_LABELS on reused superblock commit 3815a245b50124f0865415dcb606a034e97494d4 upstream. In the case when we're reusing a superblock, selinux_sb_clone_mnt_opts() fails to set set_kern_flags, with the result that nfs_clone_sb_security() incorrectly clears NFS_CAP_SECURITY_LABEL. The result is that if you mount the same NFS filesystem twice, NFS security labels are turned off, even if they would work fine if you mounted the filesystem only once. ("fixes" may be not exactly the right tag, it may be more like "fixed-other-cases-but-missed-this-one".) Cc: Scott Mayhew Cc: stable@vger.kernel.org Fixes: 0b4d3452b8b4 "security/selinux: allow security_sb_clone_mnt_opts..." Signed-off-by: J. Bruce Fields Acked-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- security/selinux/hooks.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index d6b9ed34ceae..a5d9c0146ac3 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1000,8 +1000,11 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb, BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED)); /* if fs is reusing a sb, make sure that the contexts match */ - if (newsbsec->flags & SE_SBINITIALIZED) + if (newsbsec->flags & SE_SBINITIALIZED) { + if ((kern_flags & SECURITY_LSM_NATIVE_LABELS) && !set_context) + *set_kern_flags |= SECURITY_LSM_NATIVE_LABELS; return selinux_cmp_sb_context(oldsb, newsb); + } mutex_lock(&newsbsec->lock); -- 2.20.1