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* [PATCH] mangle: check for end of string on every iteration
@ 2012-05-13 19:14 Dave Reisner
  2012-05-15  9:33 ` Karel Zak
  0 siblings, 1 reply; 2+ messages in thread
From: Dave Reisner @ 2012-05-13 19:14 UTC (permalink / raw)
  To: util-linux; +Cc: Dave Reisner

Checking for the null byte at the end of the string only conditionally
leads to segfaults, evidenced by mount helpers crashing on writes to
/run/mount/utab. Simply check for the null on each iteration, and append
a null byte to the mangled string before breaking.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
---
 lib/mangle.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/mangle.c b/lib/mangle.c
index e1b4814..656918c 100644
--- a/lib/mangle.c
+++ b/lib/mangle.c
@@ -31,16 +31,17 @@ char *mangle(const char *s)
 	if (!sp)
 		return NULL;
 	while(1) {
+		if (!*s) {
+			*sp = '\0';
+			break;
+		}
 		if (is_unwanted_char(*s)) {
 			*sp++ = '\\';
 			*sp++ = '0' + ((*s & 0300) >> 6);
 			*sp++ = '0' + ((*s & 070) >> 3);
 			*sp++ = '0' + (*s & 07);
-		} else {
+		} else
 			*sp++ = *s;
-			if (!*s)
-				break;
-		}
 		s++;
 	}
 	return ss;
-- 
1.7.10.2


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] mangle: check for end of string on every iteration
  2012-05-13 19:14 [PATCH] mangle: check for end of string on every iteration Dave Reisner
@ 2012-05-15  9:33 ` Karel Zak
  0 siblings, 0 replies; 2+ messages in thread
From: Karel Zak @ 2012-05-15  9:33 UTC (permalink / raw)
  To: Dave Reisner; +Cc: util-linux

On Sun, May 13, 2012 at 03:14:49PM -0400, Dave Reisner wrote:
> Checking for the null byte at the end of the string only conditionally
> leads to segfaults, evidenced by mount helpers crashing on writes to

 Ah.. sorry.

> /run/mount/utab. Simply check for the null on each iteration, and append
> a null byte to the mangled string before breaking.
> 
> Signed-off-by: Dave Reisner <dreisner@archlinux.org>
> ---
>  lib/mangle.c |    9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)

 Applied, thanks!

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

^ permalink raw reply	[flat|nested] 2+ messages in thread

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