split cap_mmap_addr() out of cap_file_mmap()

... switch callers.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/security.h

@@ -86,6 +86,7 @@ extern int cap_inode_setxattr(struct dentry *dentry, const char *name,
 extern int cap_inode_removexattr(struct dentry *dentry, const char *name);
 extern int cap_inode_need_killpriv(struct dentry *dentry);
 extern int cap_inode_killpriv(struct dentry *dentry);
+extern int cap_mmap_addr(unsigned long addr);
 extern int cap_file_mmap(struct file *file, unsigned long reqprot,
 			 unsigned long prot, unsigned long flags,
 			 unsigned long addr, unsigned long addr_only);
@@ -2187,7 +2188,7 @@ static inline int security_file_mmap(struct file *file, unsigned long reqprot,
 				     unsigned long addr,
 				     unsigned long addr_only)
 {
-	return cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	return cap_mmap_addr(addr);
 }
 
 static inline int security_file_mprotect(struct vm_area_struct *vma,

security/apparmor/lsm.c

@@ -497,7 +497,7 @@ static int apparmor_file_mmap(struct file *file, unsigned long reqprot,
 	int rc = 0;
 
 	/* do DAC check */
-	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	rc = cap_mmap_addr(addr);
 	if (rc || addr_only)
 		return rc;
 

security/commoncap.c

@@ -957,6 +957,29 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
 	return __vm_enough_memory(mm, pages, cap_sys_admin);
 }
 
+/*
+ * cap_mmap_addr - check if able to map given addr
+ * @addr: address attempting to be mapped
+ *
+ * If the process is attempting to map memory below dac_mmap_min_addr they need
+ * CAP_SYS_RAWIO.  The other parameters to this function are unused by the
+ * capability security module.  Returns 0 if this mapping should be allowed
+ * -EPERM if not.
+ */
+int cap_mmap_addr(unsigned long addr)
+{
+	int ret = 0;
+
+	if (addr < dac_mmap_min_addr) {
+		ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO,
+				  SECURITY_CAP_AUDIT);
+		/* set PF_SUPERPRIV if it turns out we allow the low mmap */
+		if (ret == 0)
+			current->flags |= PF_SUPERPRIV;
+	}
+	return ret;
+}
+
 /*
  * cap_file_mmap - check if able to map given addr
  * @file: unused
@@ -975,14 +998,5 @@ int cap_file_mmap(struct file *file, unsigned long reqprot,
 		  unsigned long prot, unsigned long flags,
 		  unsigned long addr, unsigned long addr_only)
 {
-	int ret = 0;
-
-	if (addr < dac_mmap_min_addr) {
-		ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO,
-				  SECURITY_CAP_AUDIT);
-		/* set PF_SUPERPRIV if it turns out we allow the low mmap */
-		if (ret == 0)
-			current->flags |= PF_SUPERPRIV;
-	}
-	return ret;
+	return cap_mmap_addr(addr);
 }

security/selinux/hooks.c

@@ -3104,7 +3104,7 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
 	}
 
 	/* do DAC check on address space usage */
-	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	rc = cap_mmap_addr(addr);
 	if (rc || addr_only)
 		return rc;
 

security/smack/smack_lsm.c

@@ -1199,7 +1199,7 @@ static int smack_file_mmap(struct file *file,
 	int rc;
 
 	/* do DAC check on address space usage */
-	rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
+	rc = cap_mmap_addr(addr);
 	if (rc || addr_only)
 		return rc;