[Midnightbsd-cvs] src [7172] trunk/lib/libelf/elf_scn.c: Avoid integer overflow and reading past EOF with elf headers.

[laffer1 at midnightbsd.org]

Revision: 7172
          http://svnweb.midnightbsd.org/src/?rev=7172
Author:   laffer1
Date:     2015-07-26 17:59:33 -0400 (Sun, 26 Jul 2015)
Log Message:
-----------
Avoid integer overflow and reading past EOF with elf headers.

Obtained from: FreeBSD 10-stable

Modified Paths:
--------------
    trunk/lib/libelf/elf_scn.c

Modified: trunk/lib/libelf/elf_scn.c
===================================================================
--- trunk/lib/libelf/elf_scn.c	2015-07-26 21:50:20 UTC (rev 7171)
+++ trunk/lib/libelf/elf_scn.c	2015-07-26 21:59:33 UTC (rev 7172)
@@ -31,6 +31,7 @@
 #include <errno.h>
 #include <gelf.h>
 #include <libelf.h>
+#include <stdint.h>
 #include <stdlib.h>
 
 #include "_libelf.h"
@@ -55,8 +56,10 @@
 	assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0);
 
 #define	CHECK_EHDR(E,EH)	do {				\
-		if (fsz != (EH)->e_shentsize ||			\
-		    shoff + fsz * shnum > e->e_rawsize) {	\
+		if (shoff > e->e_rawsize ||			\
+		    fsz != (EH)->e_shentsize ||			\
+		    shnum > SIZE_MAX / fsz ||			\
+		    fsz * shnum > e->e_rawsize - shoff) {	\
 			LIBELF_SET_ERROR(HEADER, 0);		\
 			return (0);				\
 		}						\