linux-kernel - [PATCH 0/2] kprobes: Remove kprobe::fault

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-next>] [day] [month] [year] [list]

Date:   Tue, 25 May 2021 09:25:18 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     mhiramat@...nel.org
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        mingo@...nel.org, rostedt@...dmis.org,
        naveen.n.rao@...ux.vnet.ibm.com, ananth@...ux.ibm.com,
        x86@...nel.org
Subject: [PATCH 0/2] kprobes: Remove kprobe::fault_handler

The reason for kprobe::fault_handler(), as given by their comment:

* We come here because instructions in the pre/post
* handler caused the page_fault, this could happen
* if handler tries to access user space by
* copy_from_user(), get_user() etc. Let the
* user-specified handler try to fix it first.

Is just plain bad. Those other handlers are ran from non-preemptible
context and had better use _nofault() functions. Also, there is no
upstream usage of this.

The corollary of this change is that no tracing/probing/whatever can consume
faults.