Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751187AbdFALv2 (ORCPT ); Thu, 1 Jun 2017 07:51:28 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:7298 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751096AbdFALv1 (ORCPT ); Thu, 1 Jun 2017 07:51:27 -0400 Subject: Re: [PATCH] modpost: abort if a module name is too long To: Jessica Yu References: <1495266381-14755-1-git-send-email-xiexiuqi@huawei.com> <20170529091007.e3zhsasmcxhzexx6@jeyu> <20170531033042.mtrmcj6odvn2bmxs@jeyu> CC: , Xie XiuQi , , , , , , From: Wanlong Gao Message-ID: <23f3b0e2-dcc6-2165-68d6-a88fac1ba9ff@huawei.com> Date: Thu, 1 Jun 2017 19:51:17 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.97.93] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.592FFFBD.0120,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 072a57e691b18536369218de3e782316 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4007 Lines: 129 Jessica, On 2017/5/31 11:48, Wanlong Gao wrote: > > > On 2017/5/31 11:30, Jessica Yu wrote: >> +++ Wanlong Gao [31/05/17 10:23 +0800]: >>> Hi Jessica, >>> >>> On 2017/5/29 17:10, Jessica Yu wrote: >>>> +++ Xie XiuQi [20/05/17 15:46 +0800]: >>>>> From: Wanlong Gao >>>>> >>>>> Module name has a limited length, but currently the build system >>>>> allows the build finishing even if the module name is too long. >>>>> >>>>> CC /root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.o >>>>> /root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.c:9:2: >>>>> warning: initializer-string for array of chars is too long [enabled by default] >>>>> .name = KBUILD_MODNAME, >>>>> ^ >>>>> >>>>> but it's merely a warning. >>>>> >>>>> This patch adds the check of the module name length in modpost and stops >>>>> the build properly. >>>>> >>>>> Signed-off-by: Wanlong Gao >>>>> Signed-off-by: Xie XiuQi >>>>> --- >>>>> scripts/mod/modpost.c | 11 +++++++++++ >>>>> 1 file changed, 11 insertions(+) >>>>> >>>>> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c >>>>> index 30d752a..db11c57 100644 >>>>> --- a/scripts/mod/modpost.c >>>>> +++ b/scripts/mod/modpost.c >>>>> @@ -2166,6 +2166,17 @@ static int add_versions(struct buffer *b, struct module *mod) >>>>> { >>>>> struct symbol *s, *exp; >>>>> int err = 0; >>>>> + const char *mod_name; >>>>> + >>>>> + mod_name = strrchr(mod->name, '/'); >>>>> + if (mod_name == NULL) >>>>> + mod_name = mod->name; >>>>> + else >>>>> + mod_name++; >>>>> + if (strlen(mod_name) >= MODULE_NAME_LEN) { >>>>> + merror("module name is too long [%s.ko]\n", mod->name); >>>>> + return 1; >>>>> + } >>>> >>>> Hi Xie, >>>> >>>> This check shouldn't be in add_versions() (which does something else entirely), >>>> it should probably be put in a separate helper function called from main. But >>>> I'm not a big fan of the extra string manipulation to do something this simple. >>>> >>>> I think this check can be vastly simplified, how about something like the >>>> following? >>> >>> This looks better, would you apply your following patch? >>> >>> Reviewed-by: Wanlong Gao >>> Tested-by: Wanlong Gao >> >> Sure, thanks for testing. I'll go ahead and format this into a proper >> patch and resend. > > Please wait, I just found that this patch makes the built module can't > be inserted by the following error: > > # insmod abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabc.ko > insmod: ERROR: could not insert module abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabc.ko: Invalid parameters > > # dmesg > abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabc: Unknown symbol __fentry__ (err -22) > > Any idea about this error? Thanks, Wanlong Gao > Thanks, > Wanlong Gao > >> >> Jessica >> >>>> >>>> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c >>>> index 48397fe..bb09fc7 100644 >>>> --- a/scripts/mod/modpost.c >>>> +++ b/scripts/mod/modpost.c >>>> @@ -2139,6 +2139,9 @@ static void add_header(struct buffer *b, struct module *mod) >>>> "#endif\n"); >>>> buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); >>>> buf_printf(b, "};\n"); >>>> + buf_printf(b, "\n"); >>>> + buf_printf(b, "static void __attribute__((section(\".discard\"), used)) __modname_test(void)\n"); >>>> + buf_printf(b, "{ BUILD_BUG_ON(sizeof(KBUILD_MODNAME) > MODULE_NAME_LEN); }\n"); >>>> } >>>> >>>> static void add_intree_flag(struct buffer *b, int is_intree) >>>> >>>> This simply checks if KBUILD_MODNAME > MODULE_NAME_LEN and breaks the build if >>>> it does. >>>> >>>> Jessica >>>> >>>>> for (s = mod->unres; s; s = s->next) { >>>>> exp = find_symbol(s->name); >>>>> -- >>>>> 1.8.3.1 >>>>> >>>> >>>> . >>>> >>> >> >> . >> > > > . >