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From e40ba375b6007ff227d18aa55be7f1070145ccac Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Fri, 7 Nov 2014 17:18:07 +0100
Subject: [PATCH 20/41] dump: fill in the flat header signature more pleasingly
 to the eye

Message-id: <1415380693-16593-21-git-send-email-lersek@redhat.com>
Patchwork-id: 62206
O-Subject: [RHEL-7.1 qemu-kvm PATCH 20/26] dump: fill in the flat header signature more pleasingly to the eye
Bugzilla: 1157798
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
RH-Acked-by: dgibson <dgibson@redhat.com>

The "mh.signature" array field has size 16, and is zeroed by the preceding
memset(). MAKEDUMPFILE_SIGNATURE expands to a string literal with string
length 12 (size 13). There's no need to measure the length of
MAKEDUMPFILE_SIGNATURE at runtime, nor for the extra zero-filling of
"mh.signature" with strncpy().

Use memcpy() with MIN(sizeof, sizeof) for robustness (which is an integer
constant expression, evaluable at compile time.)

Approximately-suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
(cherry picked from commit ae3f88f60fb9f42bb3679311c2fbff8e1868ea47)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 dump.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dump.c b/dump.c
index 9250594..533b914 100644
--- a/dump.c
+++ b/dump.c
@@ -722,8 +722,8 @@ static int write_start_flat_header(int fd)
     int ret = 0;
 
     memset(&mh, 0, sizeof(mh));
-    strncpy(mh.signature, MAKEDUMPFILE_SIGNATURE,
-            strlen(MAKEDUMPFILE_SIGNATURE));
+    memcpy(mh.signature, MAKEDUMPFILE_SIGNATURE,
+           MIN(sizeof mh.signature, sizeof MAKEDUMPFILE_SIGNATURE));
 
     mh.type = cpu_to_be64(TYPE_FLAT_HEADER);
     mh.version = cpu_to_be64(VERSION_FLAT_HEADER);
-- 
1.8.3.1