From: Alexander Kuleshov <kuleshovmail@gmail.com>
Date: Tue, 8 Dec 2015 18:38:12 +0000 (+0600)
Subject: boot0cfg: check result of malloc in read_mbr()
X-Git-Tag: v4.6.0rc~1126
X-Git-Url: https://gitweb.dragonflybsd.org/~tuxillo/dragonfly.git/commitdiff_plain/5f115e3b8fa054dfb6e59af424b0946871ca6cc0

boot0cfg: check result of malloc in read_mbr()

We allocating buffer for MBR in the read_mbr() function. The malloc()
may return NULL, so this patch checks the result of the malloc and
exit with the error if we can't allocate memory.

Besides this we close file descriptor.
---

diff --git a/usr.sbin/boot0cfg/boot0cfg.c b/usr.sbin/boot0cfg/boot0cfg.c
index 53e7e95ea5..4694f17f03 100644
--- a/usr.sbin/boot0cfg/boot0cfg.c
+++ b/usr.sbin/boot0cfg/boot0cfg.c
@@ -24,7 +24,6 @@
  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.7.2.4 2002/03/16 01:06:51 mikeh Exp $
- * $DragonFly: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.6 2008/03/24 23:04:19 swildner Exp $
  */
 
 #include <sys/param.h>
@@ -238,11 +237,14 @@ read_mbr(const char *disk, u_int8_t **mbr, int check_version)
 	    err(1, "%s", disk);
 	if (n != mbr_size)
 	    errx(1, "%s: short read", disk);
+	close(fd);
 	return (mbr_size);
     }
-    *mbr = malloc(sizeof(buf));
-    memcpy(*mbr, buf, sizeof(buf));
 
+    if ((*mbr = malloc(sizeof(buf))) == NULL)
+	errx(1, "%s: unable to allocate mbr buffer", disk);
+    memcpy(*mbr, buf, sizeof(buf));
+    close(fd);
     return sizeof(buf);
 }