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Date:      Fri, 2 Dec 2016 19:02:13 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org
Subject:   svn commit: r309426 - in stable: 10/sys/amd64/amd64 10/sys/amd64/include 10/sys/i386/i386 10/sys/i386/include 11/sys/amd64/amd64 11/sys/i386/i386 11/sys/x86/include
Message-ID:  <201612021902.uB2J2Dn0070366@repo.freebsd.org>
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Author: jhb
Date: Fri Dec  2 19:02:12 2016
New Revision: 309426
URL: https://svnweb.freebsd.org/changeset/base/309426

Log:
  MFC 303753,308004: Add bounds checking on addresses used with /dev/mem.
  
  303753:
  Don't permit mappings of invalid physical addresses on amd64 via /dev/mem.
  
  308004:
  MFamd64: Add bounds checks on addresses used with /dev/mem.
  
  Reject attempts to read from or memory map offsets in /dev/mem that are
  beyond the maximum-supported physical address of the current CPU.

Modified:
  stable/11/sys/amd64/amd64/mem.c
  stable/11/sys/i386/i386/mem.c
  stable/11/sys/x86/include/x86_var.h
Directory Properties:
  stable/11/   (props changed)

Changes in other areas also in this revision:
Modified:
  stable/10/sys/amd64/amd64/mem.c
  stable/10/sys/amd64/include/md_var.h
  stable/10/sys/i386/i386/mem.c
  stable/10/sys/i386/include/md_var.h
Directory Properties:
  stable/10/   (props changed)

Modified: stable/11/sys/amd64/amd64/mem.c
==============================================================================
--- stable/11/sys/amd64/amd64/mem.c	Fri Dec  2 18:03:15 2016	(r309425)
+++ stable/11/sys/amd64/amd64/mem.c	Fri Dec  2 19:02:12 2016	(r309426)
@@ -140,7 +140,7 @@ memrw(struct cdev *dev, struct uio *uio,
 				error = uiomove((void *)vd, c, uio);
 				break;
 			}
-			if (v >= (1ULL << cpu_maxphyaddr)) {
+			if (v > cpu_getmaxphyaddr()) {
 				error = EFAULT;
 				break;
 			}
@@ -168,9 +168,11 @@ int
 memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
     int prot __unused, vm_memattr_t *memattr __unused)
 {
-	if (dev2unit(dev) == CDEV_MINOR_MEM)
+	if (dev2unit(dev) == CDEV_MINOR_MEM) {
+		if (offset > cpu_getmaxphyaddr())
+			return (-1);
 		*paddr = offset;
-	else if (dev2unit(dev) == CDEV_MINOR_KMEM)
+	} else if (dev2unit(dev) == CDEV_MINOR_KMEM)
         	*paddr = vtophys(offset);
 	/* else panic! */
 	return (0);

Modified: stable/11/sys/i386/i386/mem.c
==============================================================================
--- stable/11/sys/i386/i386/mem.c	Fri Dec  2 18:03:15 2016	(r309425)
+++ stable/11/sys/i386/i386/mem.c	Fri Dec  2 19:02:12 2016	(r309426)
@@ -108,8 +108,11 @@ memrw(struct cdev *dev, struct uio *uio,
 			continue;
 		}
 		if (dev2unit(dev) == CDEV_MINOR_MEM) {
-			pa = uio->uio_offset;
-			pa &= ~PAGE_MASK;
+			if (uio->uio_offset > cpu_getmaxphyaddr()) {
+				error = EFAULT;
+				break;
+			}
+			pa = trunc_page(uio->uio_offset);
 		} else {
 			/*
 			 * Extract the physical page since the mapping may
@@ -161,9 +164,11 @@ int
 memmmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
     int prot __unused, vm_memattr_t *memattr __unused)
 {
-	if (dev2unit(dev) == CDEV_MINOR_MEM)
+	if (dev2unit(dev) == CDEV_MINOR_MEM) {
+		if (offset > cpu_getmaxphyaddr())
+			return (-1);
 		*paddr = offset;
-	else if (dev2unit(dev) == CDEV_MINOR_KMEM)
+	} else if (dev2unit(dev) == CDEV_MINOR_KMEM)
         	*paddr = vtophys(offset);
 	/* else panic! */
 	return (0);

Modified: stable/11/sys/x86/include/x86_var.h
==============================================================================
--- stable/11/sys/x86/include/x86_var.h	Fri Dec  2 18:03:15 2016	(r309425)
+++ stable/11/sys/x86/include/x86_var.h	Fri Dec  2 19:02:12 2016	(r309426)
@@ -94,6 +94,20 @@ struct	trapframe;
  */
 typedef void alias_for_inthand_t(void);
 
+/*
+ * Returns the maximum physical address that can be used with the
+ * current system.
+ */
+static __inline vm_paddr_t
+cpu_getmaxphyaddr(void)
+{
+#if defined(__i386__) && !defined(PAE)
+	return (0xffffffff);
+#else
+	return ((1ULL << cpu_maxphyaddr) - 1);
+#endif
+}
+
 void	*alloc_fpusave(int flags);
 void	busdma_swi(void);
 bool	cpu_mwait_usable(void);

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