Commit 95ffe194204a ("selinux: refactor mls_context_to_sid() and make
it stricter") inadvertently changed how we handle labels that did not
contain MLS information. This patch restores the proper behavior in
mls_context_to_sid() and adds a comment explaining the proper
behavior to help ensure this doesn't happen again.
Fixes: 95ffe194204a ("selinux: refactor mls_context_to_sid() and make it stricter")
Reported-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
---
security/selinux/ss/mls.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 2fe459df3c85..b7efa2296969 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -245,9 +245,13 @@ int mls_context_to_sid(struct policydb *pol,
char *rangep[2];
if (!pol->mls_enabled) {
- if ((def_sid != SECSID_NULL && oldc) || (*scontext) == '\0')
- return 0;
- return -EINVAL;
+ /*
+ * With no MLS, only return -EINVAL if there is a MLS field
+ * and it did not come from an xattr.
+ */
+ if (oldc && def_sid == SECSID_NULL)
+ return -EINVAL;
+ return 0;
}
/*
