svn commit: r309647 - stable/11/lib/libvmmapi

[Gleb Smirnoff]

Author: glebius
Date: Tue Dec  6 18:54:43 2016
New Revision: 309647
URL: https://svnweb.freebsd.org/changeset/base/309647

Log:
  Merge r309640 from head:
  
    Fix possible integer overflow in guest memory bounds checking, which could
    lead to access from the virtual machine to the heap of the bhyve(8) process.
  
  Submitted by:	Felix Wilhelm <fwilhelm ernw.de>
  Patch by:	grehan
  Security:	FreeBSD-SA-16:38.bhyve

Modified:
  stable/11/lib/libvmmapi/vmmapi.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/lib/libvmmapi/vmmapi.c
==============================================================================
--- stable/11/lib/libvmmapi/vmmapi.c	Tue Dec  6 18:54:04 2016	(r309646)
+++ stable/11/lib/libvmmapi/vmmapi.c	Tue Dec  6 18:54:43 2016	(r309647)
@@ -426,13 +426,18 @@ vm_map_gpa(struct vmctx *ctx, vm_paddr_t
 {
 
 	if (ctx->lowmem > 0) {
-		if (gaddr < ctx->lowmem && gaddr + len <= ctx->lowmem)
+		if (gaddr < ctx->lowmem && len <= ctx->lowmem &&
+		    gaddr + len <= ctx->lowmem)
 			return (ctx->baseaddr + gaddr);
 	}
 
 	if (ctx->highmem > 0) {
-		if (gaddr >= 4*GB && gaddr + len <= 4*GB + ctx->highmem)
-			return (ctx->baseaddr + gaddr);
+                if (gaddr >= 4*GB) {
+			if (gaddr < 4*GB + ctx->highmem &&
+			    len <= ctx->highmem &&
+			    gaddr + len <= 4*GB + ctx->highmem)
+				return (ctx->baseaddr + gaddr);
+		}
 	}
 
 	return (NULL);