1 files changed, 30 insertions, 10 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 15c2a08a66f1..5dee88362e71 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1854,12 +1854,12 @@ static inline u32 open_file_to_av(struct file *file)
 
 /* Hook functions begin here. */
 
-static int selinux_ptrace_may_access(struct task_struct *child,
+static int selinux_ptrace_access_check(struct task_struct *child,
 				     unsigned int mode)
 {
 	int rc;
 
-	rc = cap_ptrace_may_access(child, mode);
+	rc = cap_ptrace_access_check(child, mode);
 	if (rc)
 		return rc;
 
@@ -2938,11 +2938,6 @@ static int selinux_revalidate_file_permission(struct file *file, int mask)
 	const struct cred *cred = current_cred();
 	struct inode *inode = file->f_path.dentry->d_inode;
 
-	if (!mask) {
-		/* No permission to check.  Existence test. */
-		return 0;
-	}
-
 	/* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
 	if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
 		mask |= MAY_APPEND;
@@ -2953,10 +2948,20 @@ static int selinux_revalidate_file_permission(struct file *file, int mask)
 
 static int selinux_file_permission(struct file *file, int mask)
 {
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct file_security_struct *fsec = file->f_security;
+	struct inode_security_struct *isec = inode->i_security;
+	u32 sid = current_sid();
+
 	if (!mask)
 		/* No permission to check.  Existence test. */
 		return 0;
 
+	if (sid == fsec->sid && fsec->isid == isec->sid &&
+	    fsec->pseqno == avc_policy_seqno())
+		/* No change since dentry_open check. */
+		return 0;
+
 	return selinux_revalidate_file_permission(file, mask);
 }
 
@@ -3029,9 +3034,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
 	int rc = 0;
 	u32 sid = current_sid();
 
-	if (addr < mmap_min_addr)
+	/*
+	 * notice that we are intentionally putting the SELinux check before
+	 * the secondary cap_file_mmap check.  This is such a likely attempt
+	 * at bad behaviour/exploit that we always want to get the AVC, even
+	 * if DAC would have also denied the operation.
+	 */
+	if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
 		rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
 				  MEMPROTECT__MMAP_ZERO, NULL);
+		if (rc)
+			return rc;
+	}
+
+	/* do DAC check on address space usage */
+	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
 	if (rc || addr_only)
 		return rc;
 
@@ -5182,7 +5199,7 @@ static int selinux_setprocattr(struct task_struct *p,
 
 		/* Only allow single threaded processes to change context */
 		error = -EPERM;
-		if (!is_single_threaded(p)) {
+		if (!current_is_single_threaded()) {
 			error = security_bounded_transition(tsec->sid, sid);
 			if (error)
 				goto abort_change;
@@ -5310,7 +5327,7 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer)
 static struct security_operations selinux_ops = {
 	.name =				"selinux",
 
-	.ptrace_may_access =		selinux_ptrace_may_access,
+	.ptrace_access_check =		selinux_ptrace_access_check,
 	.ptrace_traceme =		selinux_ptrace_traceme,
 	.capget =			selinux_capget,
 	.capset =			selinux_capset,
@@ -5678,6 +5695,9 @@ int selinux_disable(void)
 	selinux_disabled = 1;
 	selinux_enabled = 0;
 
+	/* Try to destroy the avc node cache */
+	avc_disable();
+
 	/* Reset security_ops to the secondary module, dummy or capability. */
 	security_ops = secondary_ops;