From: Jeff King <peff@peff.net>
To: Michael Mueller <mmueller@vigilantsw.com>
Cc: "René Scharfe" <rene.scharfe@lsrfire.ath.cx>, git@vger.kernel.org
Subject: Re: Possible segfault introduced in commit.c
Date: Wed, 25 Apr 2012 07:14:35 -0400 [thread overview]
Message-ID: <20120425111435.GA21579@sigill.intra.peff.net> (raw)
In-Reply-To: <CANV9Rr_ev+34Wd030cps0UbgjRYD0=L2DQhbrCOkBVWG-2xaug@mail.gmail.com>
On Wed, Apr 25, 2012 at 12:59:28AM -0700, Michael Mueller wrote:
> As you might already know, we analyze git regularly with Sentry (our
> static analysis tool). Today it picked up a new NULL pointer
> dereference in commit.c:366:
>
> void commit_list_reverse(struct commit_list **list_p)
> {
> struct commit_list *prev = NULL, *curr = *list_p, *next;
>
> if (!list_p)
> return;
> /* function continues... */
> }
>
> list_p is dereferenced on the first line, then tested for NULL on
> the very next statement. If it's possible that list_p is NULL, this
> will be a segfault. If it can't be NULL, then the check is
> unnecessary (and probably misleading).
Yes, you're right. There is only one caller currently, and it can never
be NULL (it passes the address-of a pointer variable). I think dropping
the NULL-check is the right thing; even an empty list will still have a
pointer to its NULL head.
-Peff
next prev parent reply other threads:[~2012-04-25 11:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-25 7:59 Possible segfault introduced in commit.c Michael Mueller
2012-04-25 11:14 ` Jeff King [this message]
2012-04-25 20:22 ` René Scharfe
2012-04-25 20:35 ` [PATCH 1/3] sequencer: export commit_list_append() René Scharfe
2012-04-25 22:03 ` Junio C Hamano
2012-04-30 21:07 ` René Scharfe
2012-04-25 20:35 ` [PATCH 2/3] revision: append to list instead of insert and reverse René Scharfe
2012-04-25 20:35 ` [PATCH 3/3] commit: remove commit_list_reverse() René Scharfe
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