From: semarie <semarie@openbsd.org>
Date: Tue, 23 Jun 2015 13:43:08 +0000 (+0000)
Subject: add some check before accessing data:
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=642c3e06fd11b59af4550a00ec59dd254d055316;p=openbsd

add some check before accessing data:
 - if section header table is be present
 - consistency of section header table size

ok miod@
---

diff --git a/usr.bin/nm/elf.c b/usr.bin/nm/elf.c
index c1033bb12e7..17906a44d47 100644
--- a/usr.bin/nm/elf.c
+++ b/usr.bin/nm/elf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: elf.c,v 1.28 2015/05/17 20:19:08 guenther Exp $	*/
+/*	$OpenBSD: elf.c,v 1.29 2015/06/23 13:43:08 semarie Exp $	*/
 
 /*
  * Copyright (c) 2003 Michael Shalayeff
@@ -149,6 +149,16 @@ elf_load_shdrs(const char *name, FILE *fp, off_t foff, Elf_Ehdr *head)
 
 	elf_fix_header(head);
 
+	if (head->e_shnum == 0) {
+		warnx("%s: no section header table", name);
+		return (NULL);
+	}
+
+	if (head->e_shstrndx >= head->e_shnum) {
+		warnx("%s: inconsistent section header table", name);
+		return (NULL);
+	}
+
 	if ((shdr = calloc(head->e_shentsize, head->e_shnum)) == NULL) {
 		warn("%s: malloc shdr", name);
 		return (NULL);