Author: nwhitehorn
Date: Thu Sep 2 22:26:49 2010
New Revision: 212165
URL: http://svn.freebsd.org/changeset/base/212165
Log:
In the case of non-sequential mappings, ofw_mapmem() could ask Open
Firmware to map a memory region with negative length, causing crashes
and Undefined Behavior. Add the appropriate check to make the behavior
defined.
Modified:
head/sys/boot/ofw/libofw/ofw_copy.c
Modified: head/sys/boot/ofw/libofw/ofw_copy.c
==============================================================================
--- head/sys/boot/ofw/libofw/ofw_copy.c Thu Sep 2 21:52:43 2010
(r212164)
+++ head/sys/boot/ofw/libofw/ofw_copy.c Thu Sep 2 22:26:49 2010
(r212165)
@@ -68,7 +68,7 @@ ofw_mapmem(vm_offset_t dest, const size_
/*
* Trim area covered by existing mapping, if any
*/
- if (dest < (last_dest + last_len)) {
+ if (dest < (last_dest + last_len) && dest >= last_dest) {
nlen -= (last_dest + last_len) - dest;
dest = last_dest + last_len;
}
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