[PATCH] win32: plug memory leak on realloc() failure in syslog()

[PATCH] win32: plug memory leak on realloc() failure in syslog()

[René Scharfe]

If realloc() fails then the original buffer is still valid.  Free it
before exiting the function.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 compat/win32/syslog.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/compat/win32/syslog.c b/compat/win32/syslog.c
index 6c7c9b6053..161978d720 100644
--- a/compat/win32/syslog.c
+++ b/compat/win32/syslog.c
@@ -43,8 +43,10 @@ void syslog(int priority, const char *fmt, ...)
 	va_end(ap);
 
 	while ((pos = strstr(str, "%1")) != NULL) {
+		char *oldstr = str;
 		str = realloc(str, st_add(++str_len, 1));
 		if (!str) {
+			free(oldstr);
 			warning_errno("realloc failed");
 			return;
 		}
-- 
2.14.0

Re: [PATCH] win32: plug memory leak on realloc() failure in syslog()

[Johannes Schindelin]

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Hi René,

On Thu, 10 Aug 2017, René Scharfe wrote:

> If realloc() fails then the original buffer is still valid.  Free it
> before exiting the function.
> 
> Signed-off-by: Rene Scharfe <l.s.r@web.de>

The subject had me worried for a second... The realloc() fails so rarely
that I, for one, have never encountered that problem.

Still, it is a correct fix for a real bug.

Thanks,
Dscho