1 files changed, 68 insertions, 8 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ef3bd9d61c38..34e3351239d8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -242,11 +242,63 @@ static int inode_alloc_security(struct inode *inode)
 	return 0;
 }
 
+static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
+
+/*
+ * Try reloading inode security labels that have been marked as invalid.  The
+ * @may_sleep parameter indicates when sleeping and thus reloading labels is
+ * allowed; when set to false, returns ERR_PTR(-ECHILD) when the label is
+ * invalid.  The @opt_dentry parameter should be set to a dentry of the inode;
+ * when no dentry is available, set it to NULL instead.
+ */
+static int __inode_security_revalidate(struct inode *inode,
+				       struct dentry *opt_dentry,
+				       bool may_sleep)
+{
+	struct inode_security_struct *isec = inode->i_security;
+
+	might_sleep_if(may_sleep);
+
+	if (isec->initialized == LABEL_INVALID) {
+		if (!may_sleep)
+			return -ECHILD;
+
+		/*
+		 * Try reloading the inode security label.  This will fail if
+		 * @opt_dentry is NULL and no dentry for this inode can be
+		 * found; in that case, continue using the old label.
+		 */
+		inode_doinit_with_dentry(inode, opt_dentry);
+	}
+	return 0;
+}
+
+static void inode_security_revalidate(struct inode *inode)
+{
+	__inode_security_revalidate(inode, NULL, true);
+}
+
+static struct inode_security_struct *inode_security_novalidate(struct inode *inode)
+{
+	return inode->i_security;
+}
+
+static struct inode_security_struct *inode_security_rcu(struct inode *inode, bool rcu)
+{
+	int error;
+
+	error = __inode_security_revalidate(inode, NULL, !rcu);
+	if (error)
+		return ERR_PTR(error);
+	return inode->i_security;
+}
+
 /*
  * Get the security label of an inode.
  */
 static struct inode_security_struct *inode_security(struct inode *inode)
 {
+	__inode_security_revalidate(inode, NULL, true);
 	return inode->i_security;
 }
 
@@ -257,6 +309,7 @@ static struct inode_security_struct *backing_inode_security(struct dentry *dentr
 {
 	struct inode *inode = d_backing_inode(dentry);
 
+	__inode_security_revalidate(inode, dentry, true);
 	return inode->i_security;
 }
 
@@ -363,8 +416,6 @@ static const char *labeling_behaviors[7] = {
 	"uses native labeling",
 };
 
-static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
-
 static inline int inode_doinit(struct inode *inode)
 {
 	return inode_doinit_with_dentry(inode, NULL);
@@ -1655,6 +1706,7 @@ static inline int dentry_has_perm(const struct cred *cred,
 
 	ad.type = LSM_AUDIT_DATA_DENTRY;
 	ad.u.dentry = dentry;
+	__inode_security_revalidate(inode, dentry, true);
 	return inode_has_perm(cred, inode, av, &ad);
 }
 
@@ -1670,6 +1722,7 @@ static inline int path_has_perm(const struct cred *cred,
 
 	ad.type = LSM_AUDIT_DATA_PATH;
 	ad.u.path = *path;
+	__inode_security_revalidate(inode, path->dentry, true);
 	return inode_has_perm(cred, inode, av, &ad);
 }
 
@@ -2871,7 +2924,9 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct inode *inode,
 	ad.type = LSM_AUDIT_DATA_DENTRY;
 	ad.u.dentry = dentry;
 	sid = cred_sid(cred);
-	isec = inode_security(inode);
+	isec = inode_security_rcu(inode, rcu);
+	if (IS_ERR(isec))
+		return PTR_ERR(isec);
 
 	return avc_has_perm_flags(sid, isec->sid, isec->sclass, FILE__READ, &ad,
 				  rcu ? MAY_NOT_BLOCK : 0);
@@ -2923,7 +2978,9 @@ static int selinux_inode_permission(struct inode *inode, int mask)
 	perms = file_mask_to_av(inode->i_mode, mask);
 
 	sid = cred_sid(cred);
-	isec = inode_security(inode);
+	isec = inode_security_rcu(inode, flags & MAY_NOT_BLOCK);
+	if (IS_ERR(isec))
+		return PTR_ERR(isec);
 
 	rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd);
 	audited = avc_audit_required(perms, &avd, rc,
@@ -3232,6 +3289,7 @@ static int selinux_file_permission(struct file *file, int mask)
 		/* No change since file_open check. */
 		return 0;
 
+	inode_security_revalidate(inode);
 	return selinux_revalidate_file_permission(file, mask);
 }
 
@@ -3537,6 +3595,7 @@ static int selinux_file_open(struct file *file, const struct cred *cred)
 	 * new inode label or new policy.
 	 * This check is not redundant - do not remove.
 	 */
+	inode_security_revalidate(file_inode(file));
 	return file_path_has_perm(cred, file, open_file_to_av(file));
 }
 
@@ -4078,7 +4137,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 				      int type, int protocol, int kern)
 {
 	const struct task_security_struct *tsec = current_security();
-	struct inode_security_struct *isec = inode_security(SOCK_INODE(sock));
+	struct inode_security_struct *isec = inode_security_novalidate(SOCK_INODE(sock));
 	struct sk_security_struct *sksec;
 	int err = 0;
 
@@ -4278,9 +4337,9 @@ static int selinux_socket_accept(struct socket *sock, struct socket *newsock)
 	if (err)
 		return err;
 
-	newisec = inode_security(SOCK_INODE(newsock));
+	newisec = inode_security_novalidate(SOCK_INODE(newsock));
 
-	isec = inode_security(SOCK_INODE(sock));
+	isec = inode_security_novalidate(SOCK_INODE(sock));
 	newisec->sclass = isec->sclass;
 	newisec->sid = isec->sid;
 	newisec->initialized = LABEL_INITIALIZED;
@@ -4618,7 +4677,8 @@ static void selinux_sk_getsecid(struct sock *sk, u32 *secid)
 
 static void selinux_sock_graft(struct sock *sk, struct socket *parent)
 {
-	struct inode_security_struct *isec = inode_security(SOCK_INODE(parent));
+	struct inode_security_struct *isec =
+		inode_security_novalidate(SOCK_INODE(parent));
 	struct sk_security_struct *sksec = sk->sk_security;
 
 	if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 ||