From: Eli Zaretskii <eliz@gnu.org>
To: Pedro Alves <palves@redhat.com>
Cc: gdb-patches@sourceware.org
Subject: Re: Off-by-one error in windows-nat.c causes abort at startup
Date: Mon, 02 May 2016 16:40:00 -0000 [thread overview]
Message-ID: <83wpncl8h4.fsf@gnu.org> (raw)
In-Reply-To: <62c5fd08-c7b5-37e2-e364-381ae8377c03@redhat.com> (message from Pedro Alves on Mon, 2 May 2016 12:50:05 +0100)
> From: Pedro Alves <palves@redhat.com>
> Date: Mon, 2 May 2016 12:50:05 +0100
>
> On 04/30/2016 12:07 PM, Eli Zaretskii wrote:
>
> > Luckily, I still had GDB 7.5, which did work. Using it, I found the
> > off-by-one gotcha below (".gdbinit" is one character longer than
> > "gdb.ini"). I guess no one tested this feature when we switched from
> > using snprintf to xsnprintf...
>
> Sounds like gdb would corrupt memory before we switched to xsnprintf
> then. I'd say the problem is that the feature was added without a
> corresponding test case.
>
> > OK to commit (with a suitable ChangeLog entry, of course)?
>
> Sure.
Thanks, pushed.
> > --- gdb/windows-nat.c~ 2016-02-10 05:19:39.000000000 +0200
> > +++ gdb/windows-nat.c 2016-04-30 11:57:08.500000000 +0300
> > @@ -2711,9 +2711,9 @@ _initialize_check_for_gdb_ini (void)
> > if (access (oldini, 0) == 0)
> > {
> > int len = strlen (oldini);
> > - char *newini = (char *) alloca (len + 1);
> > + char *newini = (char *) alloca (len + 2);
> >
> > - xsnprintf (newini, len + 1, "%.*s.gdbinit",
> > + xsnprintf (newini, len + 2, "%.*s.gdbinit",
> > (int) (len - (sizeof ("gdb.ini") - 1)), oldini);
> > warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini);
>
> (I suspect this whole function could be rewritten in a clearer form...)
Like not use xsnprintf at all, and instead use strcpy/strcat, perhaps?
next prev parent reply other threads:[~2016-05-02 16:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-30 11:08 Eli Zaretskii
2016-05-02 11:50 ` Pedro Alves
2016-05-02 16:40 ` Eli Zaretskii [this message]
2016-05-02 18:01 ` Pedro Alves
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