svn commit: r309648 - stable/10/lib/libvmmapi

[Gleb Smirnoff]

Author: glebius
Date: Tue Dec  6 18:55:01 2016
New Revision: 309648
URL: https://svnweb.freebsd.org/changeset/base/309648

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/10/lib/libvmmapi/vmmapi.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/lib/libvmmapi/vmmapi.c
==============================================================================
--- stable/10/lib/libvmmapi/vmmapi.c	Tue Dec  6 18:54:43 2016	(r309647)
+++ stable/10/lib/libvmmapi/vmmapi.c	Tue Dec  6 18:55:01 2016	(r309648)
@@ -427,13 +427,18 @@ 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);