Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 6 May 2020 10:59:55 +0530
From:   Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     Guo Ren <guoren@kernel.org>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        "David S. Miller" <davem@davemloft.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Jann Horn <jannh@google.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Jens Axboe <axboe@kernel.dk>,
        Security Officers <security@kernel.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
        Naveen Rao <naveen.n.rao@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] uprobes: ensure that uprobe->offset and ->ref_ctr_offset
 are properly aligned
Message-ID: <20200506052955.GA8259@linux.vnet.ibm.com>
Reply-To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
References: <CAHk-=whQt69ApMkZF8b2Q2idMDgPpPETZeeOuZg59CrOO4025w@mail.gmail.com>
 <20200428091149.GB19958@linux.vnet.ibm.com>
 <20200428123914.GA27920@redhat.com>
 <20200504164724.GA28697@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
In-Reply-To: <20200504164724.GA28697@redhat.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

* Oleg Nesterov <oleg@redhat.com> [2020-05-04 18:47:25]:

> uprobe_write_opcode() must not cross page boundary; prepare_uprobe()
> relies on arch_uprobe_analyze_insn() which should validate "vaddr" but
> some architectures (csky, s390, and sparc) don't do this.
> 
> We can remove the BUG_ON() check in prepare_uprobe() and validate the
> offset early in __uprobe_register(). The new IS_ALIGNED() check matches
> the alignment check in arch_prepare_kprobe() on supported architectures,
> so I think that all insns must be aligned to UPROBE_SWBP_INSN_SIZE.
> 
> Another problem is __update_ref_ctr() which was wrong from the very
> beginning, it can read/write outside of kmap'ed page unless "vaddr" is
> aligned to sizeof(short), __uprobe_register() should check this too.
> 
> Cc: stable@vger.kernel.org
> Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Thanks Oleg.

Looks good to me.

Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> ---


-- 
Thanks and Regards
Srikar Dronamraju