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Date:      Sun, 6 Jan 2019 23:59:04 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r342823 - head/contrib/xz/src/common
Message-ID:  <201901062359.x06Nx4ib096419@repo.freebsd.org>

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Author: kib
Date: Sun Jan  6 23:59:04 2019
New Revision: 342823
URL: https://svnweb.freebsd.org/changeset/base/342823

Log:
  Clamp tuklib_physmem() return value to SIZE_T_MAX.
  
  On 32bit platforms it is possible to have (much) more physical RAM
  than is mappable into single address space.  In this case liblzma
  scales the value into a request to mmap more address space than it is
  theoretically possible.
  
  Reported and tested by:	pho
  Reviewed by:	delphij
  Discussed with:	emaste
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/contrib/xz/src/common/tuklib_physmem.c

Modified: head/contrib/xz/src/common/tuklib_physmem.c
==============================================================================
--- head/contrib/xz/src/common/tuklib_physmem.c	Sun Jan  6 23:43:12 2019	(r342822)
+++ head/contrib/xz/src/common/tuklib_physmem.c	Sun Jan  6 23:59:04 2019	(r342823)
@@ -45,6 +45,7 @@
 #	include <sys/systemcfg.h>
 
 #elif defined(TUKLIB_PHYSMEM_SYSCONF)
+#	include <limits.h>
 #	include <unistd.h>
 
 #elif defined(TUKLIB_PHYSMEM_SYSCTL)
@@ -145,13 +146,16 @@ tuklib_physmem(void)
 #elif defined(TUKLIB_PHYSMEM_SYSCONF)
 	const long pagesize = sysconf(_SC_PAGESIZE);
 	const long pages = sysconf(_SC_PHYS_PAGES);
-	if (pagesize != -1 && pages != -1)
+	if (pagesize != -1 && pages != -1) {
 		// According to docs, pagesize * pages can overflow.
 		// Simple case is 32-bit box with 4 GiB or more RAM,
 		// which may report exactly 4 GiB of RAM, and "long"
 		// being 32-bit will overflow. Casting to uint64_t
 		// hopefully avoids overflows in the near future.
 		ret = (uint64_t)pagesize * (uint64_t)pages;
+		if (ret > SIZE_T_MAX)
+			ret = SIZE_T_MAX;
+	}
 
 #elif defined(TUKLIB_PHYSMEM_SYSCTL)
 	int name[2] = {



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