From: Kees Cook <keescook@chromium•org>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail•com>
Cc: "nathanl@linux•ibm.com" <nathanl@linux•ibm.com>,
"bcain@quicinc•com" <bcain@quicinc•com>,
Wedson Almeida Filho <wedsonaf@gmail•com>,
"gary@garyguo•net" <gary@garyguo•net>,
"pmladek@suse•com" <pmladek@suse•com>,
"ustavoars@kernel•org" <ustavoars@kernel•org>,
"linux-kernel@vger•kernel.org" <linux-kernel@vger•kernel.org>,
"npiggin@gmail•com" <npiggin@gmail•com>,
"ojeda@kernel•org" <ojeda@kernel•org>,
Steven Rostedt <rostedt@goodmis•org>,
Masami Hiramatsu <mhiramat@kernel•org>,
"alex.gaynor@gmail•com" <alex.gaynor@gmail•com>,
"linux-hexagon@vger•kernel.org" <linux-hexagon@vger•kernel.org>,
maninder1.s@samsung•com, Onkarnath <onkarnath.1@samsung•com>,
"linuxppc-dev@lists•ozlabs.org" <linuxppc-dev@lists•ozlabs.org>
Subject: Re: [PATCH 1/1] arch:hexagon/powerpc: use KSYM_NAME_LEN in array size
Date: Tue, 30 May 2023 16:14:01 -0700 [thread overview]
Message-ID: <202305301611.34F0A680A2@keescook> (raw)
In-Reply-To: <CANiq72n_eso7_pgna8ukmEnuCQPsKYPr0NU-Ss9Nwv0VzX=etg@mail.gmail.com>
On Mon, May 29, 2023 at 04:50:45PM +0200, Miguel Ojeda wrote:
> Kees: what is the current stance on `[static N]` parameters? Something like:
>
> const char *kallsyms_lookup(unsigned long addr,
> unsigned long *symbolsize,
> unsigned long *offset,
> - char **modname, char *namebuf);
> + char **modname, char namebuf[static KSYM_NAME_LEN]);
>
> makes the compiler complain about cases like these (even if trivial):
>
> arch/powerpc/xmon/xmon.c:1711:10: error: array argument is too small;
> contains 128 elements, callee requires at least 512
> [-Werror,-Warray-bounds]
> name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr);
> ^ ~~~~~~
> ./include/linux/kallsyms.h:86:29: note: callee declares array
> parameter as static here
> char **modname, char namebuf[static KSYM_NAME_LEN]);
> ^ ~~~~~~~~~~~~~~~~~~~~~~
Wouldn't that be a good thing? (I.e. complain about the size mismatch?)
> But I only see 2 files in the kernel using `[static N]` (from 2020 and
> 2021). Should something else be used instead (e.g. `__counted_by`),
> even if constexpr-sized?.
Yeah, it seems pretty uncommon. I'd say traditionally arrays aren't
based too often, rather structs containing them.
But ultimately, yeah, everything could gain __counted_by and friends in
the future.
--
Kees Cook
next prev parent reply other threads:[~2023-05-30 23:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230529052832epcas5p4fa1b8cf25d9810d32bd2ccf012086fb3@epcas5p4.samsung.com>
2023-05-29 5:28 ` [PATCH 1/1] arch:hexagon/powerpc: use KSYM_NAME_LEN in array size Maninder Singh
2023-05-29 10:45 ` Miguel Ojeda
2023-05-29 10:57 ` Maninder Singh
2023-05-29 14:50 ` Miguel Ojeda
2023-05-30 8:06 ` Petr Mladek
2023-05-30 8:14 ` Maninder Singh
2023-05-30 23:14 ` Kees Cook [this message]
2023-06-18 14:20 ` Miguel Ojeda
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