linux-kernel - Re: [PATCH] time: Validate the usec before covert to nsec in do

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 8 Jul 2019 18:42:13 +0800
From:   "zhangxiaoxu (A)" <zhangxiaoxu5@...wei.com>
To:     Thomas Gleixner <tglx@...utronix.de>
CC:     <john.stultz@...aro.org>, <sboyd@...nel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] time: Validate the usec before covert to nsec in
 do_adjtimex



在 2019/7/8 17:24, Thomas Gleixner 写道:
> On Mon, 8 Jul 2019, ZhangXiaoxu wrote:
> 
>> When covert the usec to nsec, it will multiple 1000, it maybe
>> overflow and lead an undefined behavior.
>>
>> For example, users may input an negative tv_usec values when
>> call adjtimex syscall, then multiple 1000 maybe overflow it
>> to a positive and legal number.
>>
>> So, we should validate the usec before coverted it to nsec.
> 
> That's correct, but the actuall inject function wants to keep the sanity
> check,
timekeeping_inject_offset is called only by timekeeping_warp_clock and do_adjtimex.
The do_adjtimex already validate it, and timekeeping_warp_clock is set tv_nsec=0.
We keep the sanity check is for some other maybe use this function?
I had send a v2 to keep the sanity check in timekeeping_inject_offset.

Thanks.
> 
> Thanks,
> 
> 	tglx
> 
> .
>