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Re: Off-by-one error in windows-nat.c causes abort at startup
- From: Pedro Alves <palves at redhat dot com>
- To: Eli Zaretskii <eliz at gnu dot org>, gdb-patches at sourceware dot org
- Date: Mon, 2 May 2016 12:50:05 +0100
- Subject: Re: Off-by-one error in windows-nat.c causes abort at startup
- Authentication-results: sourceware.org; auth=none
- References: <83bn4rpd6m dot fsf at gnu dot org>
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.
>
> --- 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...)
Thanks,
Pedro Alves