linux-kernel - Re: [REVIEW][PATCH 14/22] signal/riscv: Use force_sig

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]

Message-ID: <87r2n4ei8o.fsf@xmission.com>
Date:   Tue, 24 Apr 2018 10:28:39 -0500
From:   ebiederm@...ssion.com (Eric W. Biederman)
To:     Palmer Dabbelt <palmer@...ive.com>
Cc:     linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
        albert@...ive.com, linux-riscv@...ts.infradead.org
Subject: Re: [REVIEW][PATCH 14/22] signal/riscv: Use force_sig_fault where appropriate

Palmer Dabbelt <palmer@...ive.com> writes:

> On Fri, 20 Apr 2018 07:38:03 PDT (-0700), ebiederm@...ssion.com wrote:
>> Filling in struct siginfo before calling force_sig_info a tedious and
>> error prone process, where once in a great while the wrong fields
>> are filled out, and siginfo has been inconsistently cleared.
>>
>> Simplify this process by using the helper force_sig_fault.  Which
>> takes as a parameters all of the information it needs, ensures
>> all of the fiddly bits of filling in struct siginfo are done properly
>> and then calls force_sig_info.
>>
>> In short about a 5 line reduction in code for every time force_sig_info
>> is called, which makes the calling function clearer.
>>
>> Cc: Palmer Dabbelt <palmer@...ive.com>
>> Cc: Albert Ou <albert@...ive.com>
>> Cc: linux-riscv@...ts.infradead.org
>> Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
>> ---
>>  arch/riscv/kernel/traps.c | 9 +--------
>>  1 file changed, 1 insertion(+), 8 deletions(-)
>>
>> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
>> index 48aa6471cede..3087940008f4 100644
>> --- a/arch/riscv/kernel/traps.c
>> +++ b/arch/riscv/kernel/traps.c
>> @@ -66,14 +66,7 @@ void die(struct pt_regs *regs, const char *str)
>>  static inline void do_trap_siginfo(int signo, int code,
>>  	unsigned long addr, struct task_struct *tsk)
>>  {
>> -	siginfo_t info;
>> -
>> -	clear_siginfo(&info);
>> -	info.si_signo = signo;
>> -	info.si_errno = 0;
>> -	info.si_code = code;
>> -	info.si_addr = (void __user *)addr;
>> -	force_sig_info(signo, &info, tsk);
>> +	force_sig_fault(signo, code, (void __user *)addr, tsk);
>>  }
>>
>>  void do_trap(struct pt_regs *regs, int signo, int code,
>
> If I understand this correctly, any change in behavior this causes would have
> been a bug on our end not filling out siginfo correctly?  In that case then feel
> free to add an

If this change above causes any user visible changes it is a bug.
As Christoph rightly pointed out force_sig_fault is simply the arch
generic version of do_trap_siginfo. 

Eric