systemd/0175-journal-fix-against-theoretical-undefined-behavior.patch

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From 9e32b8f531a1e15f85cce97bea931c43a9db7798 Mon Sep 17 00:00:00 2001
From: Shawn Landden <shawn@churchofgit.com>
Date: Mon, 16 Dec 2013 15:41:00 -0800
Subject: [PATCH] journal: fix against (theoretical) undefined behavior
While all the libc implementations I know return NULL when memchr's size
parameter is 0, without accessing any memory, passing NULL to memchr is
still invalid:
C11 7.24.1p2: Where an argument declared as "size_t n" specifies the length
of the array for a function, n can have the value zero on a call to that
function. Unless explicitly stated otherwise in the description of a
particular function in this subclause, pointer arguments on such a call
shall still have valid values, as described in 7.1.4. On such a call, a
function that locates a character finds no occurrence, a function that
compares two character sequences returns zero, and a function that copies
characters copies zero characters.
see http://llvm.org/bugs/show_bug.cgi?id=18247
---
src/journal/journal-file.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index 8ea258b..71ef092 100644
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -1010,7 +1010,10 @@ static int journal_file_append_data(
if (r < 0)
return r;
- eq = memchr(data, '=', size);
+ if (!data)
+ eq = NULL;
+ else
+ eq = memchr(data, '=', size);
if (eq && eq > data) {
uint64_t fp;
Object *fo;