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From:   Masami Hiramatsu <masami.hiramatsu@gmail.com>
Date:   Wed, 12 Oct 2022 13:46:50 +0100
Message-ID: <CADyE4xEUE++m7VcKq9a3_va6m_K9zZ5FTFPPT8CZqin8aZ8A2g@mail.gmail.com>
Subject: Re: [PATCH v2 0/3] tracing: Fix synthetic event bug
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     linux-kernel@vger.kernel.org,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Tom Zanussi <zanussi@kernel.org>
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Hi,

2022=E5=B9=B410=E6=9C=8812=E6=97=A5(=E6=B0=B4) 11:45 Steven Rostedt <rosted=
t@goodmis.org>:
>
>
> The follow commands caused a crash:
>
>   # cd /sys/kernel/tracing
>   # echo 's:open char file[]' > dynamic_events
>   # echo 'hist:keys=3Dcommon_pid:file=3Dfilename:onchange($file).trace(op=
en,$file)' > events/syscalls/sys_enter_openat/trigger'
>   # echo 1 > events/synthetic/open/enable
>
> BOOM!
>
> The problem is that the synthetic event field "char file[]" will read
> the value given to it as a string without any memory checks to make sure
> the address is valid. The above example will pass in the user space
> address and the sythetic event code will happily call strlen() on it
> and then strscpy() where either one will cause an oops when accessing
> user space addresses.
>
> Changes since v1: https://lore.kernel.org/all/20221011212501.773319898@go=
odmis.org/

Thanks, this series of patches looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thank you!

>
>  - Handle "(fault)" printing when there's a fault
>
> Steven Rostedt (Google) (3):
>       tracing: Move duplicate code of trace_kprobe/eprobe.c into header
>       tracing: Add "(fault)" name injection to kernel probes
>       tracing: Fix reading strings from synthetic events
>
> ----
>  kernel/trace/trace_eprobe.c       |  60 ++------------------
>  kernel/trace/trace_events_synth.c |  23 ++++++--
>  kernel/trace/trace_kprobe.c       |  60 ++------------------
>  kernel/trace/trace_probe_kernel.h | 115 ++++++++++++++++++++++++++++++++=
++++++
>  4 files changed, 142 insertions(+), 116 deletions(-)
>  create mode 100644 kernel/trace/trace_probe_kernel.h


--=20
Masami Hiramatsu
mailto:masami.hiramatsu@gmail.com