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Subject: Re: [PATCH] kernel/signal: Signal-based pre-coredump notification
Cc:     christian@brauner.io, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Khalid Aziz <khalid.aziz@oracle.com>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        Helge Deller <deller@gmx.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Dave Martin <Dave.Martin@arm.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Michal Hocko <mhocko@kernel.org>,
        Rik van Riel <riel@surriel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Roman Gushchin <guro@fb.com>,
        Marcos Paulo de Souza <marcos.souza.org@gmail.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Dominik Brodowski <linux@dominikbrodowski.net>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Jann Horn <jannh@google.com>,
        Kees Cook <keescook@chromium.org>,
        linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        "Victor Kamensky (kamensky)" <kamensky@cisco.com>,
        xe-linux-external@cisco.com, Stefan Strogin <sstrogin@cisco.com>,
        Enke Chen <enkechen@cisco.com>
References: <e7ed306f-8992-9d00-bcab-5131159e8d89@cisco.com>
 <20181013104446.b3z26rwmiripqfks@gmail.com>
From:   Enke Chen <enkechen@cisco.com>
Message-ID: <5bbe7c70-d6a8-7b37-51d4-eed9a99bc7e1@cisco.com>
Date:   Mon, 15 Oct 2018 11:39:32 -0700
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Hi, Christian:

As I replied to Jann, I will remove the code that does the setting on others
to make the code simpler and more secure.

Thanks.  -- Enke

>> +static bool set_predump_signal_perm(struct task_struct *p)
>> +{
>> +	const struct cred *cred = current_cred(), *pcred = __task_cred(p);
>> +
>> +	return uid_eq(pcred->uid, cred->euid) ||
>> +	       uid_eq(pcred->euid, cred->euid) ||
>> +	       capable(CAP_SYS_ADMIN);
> 
> So before proceeding I'd like to discuss at least two points:
> - how does this interact with the dumpability of a process?
> - do we need the capable(CAP_SYS_ADMIN) restriction to init_user_ns?
>   Seems we could make this work per-user-ns just like
>   PRCTL_SET_PDEATHSIG does?
> 
>> +}