Revert "x86: Lock down IO port access when module security is enabled"

BugLink: https://bugs.launchpad.net/bugs/1884159

This reverts commit cc223b88 to backport
an updated version.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

arch/x86/kernel/ioport.c

@@ -15,7 +15,6 @@
 #include <linux/thread_info.h>
 #include <linux/syscalls.h>
 #include <linux/bitmap.h>
-#include <linux/module.h>
 #include <asm/syscalls.h>
 
 /*
@@ -29,7 +28,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
 
 	if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
 		return -EINVAL;
-	if (turn_on && (!capable(CAP_SYS_RAWIO) || secure_modules()))
+	if (turn_on && !capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
 	/*
@@ -109,7 +108,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
 		return -EINVAL;
 	/* Trying to gain more privileges? */
 	if (level > old) {
-		if (!capable(CAP_SYS_RAWIO) || secure_modules())
+		if (!capable(CAP_SYS_RAWIO))
 			return -EPERM;
 	}
 	regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) |

drivers/char/mem.c

@@ -27,7 +27,6 @@
 #include <linux/export.h>
 #include <linux/io.h>
 #include <linux/uio.h>
-#include <linux/module.h>
 
 #include <linux/uaccess.h>
 
@@ -622,9 +621,6 @@ static ssize_t write_port(struct file *file, const char __user *buf,
 	unsigned long i = *ppos;
 	const char __user *tmp = buf;
 
-	if (secure_modules())
-		return -EPERM;
-
 	if (!access_ok(VERIFY_READ, buf, count))
 		return -EFAULT;
 	while (count-- > 0 && i < 65536) {