threads / patch / 46555

patchwin32: plug memory leak on realloc() failure in syslog()

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

## tl;dr

2 messages between Aug 10, 2017 and Aug 14, 2017. Diffs are folded; open one to read it.

replies: 1people: 2as markdown or json

René Scharfe· Aug 10, 2017, 10:23 UTC · lore

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(+)

Show changes to compat/win32/syslog.c +2 −0

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

Johannes Schindelin· Aug 14, 2017, 20:26 UTC · re: René Scharfe · lore

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

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