Security/SELinux: seperate lsm specific mmap_min_addr

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / security / selinux / hooks.c

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 15c2a08a66f1217e92028a38e861ad4981ab3fdd..5dee88362e71ce02c1e272b54c56f5737995dfaa 100644 (file)
--- 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;