Re: [PATCH 4.11 145/150] tracing: Use strlcpy() instead of strcpy() in __trace_find_cmdline()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jun 12, 2017 at 11:37:07AM -0400, Steven Rostedt wrote:
> On Mon, 12 Jun 2017 17:25:52 +0200
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> 
> > 4.11-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Amey Telawane <ameyt@codeaurora.org>
> > 
> > commit e09e28671cda63e6308b31798b997639120e2a21 upstream.
> > 
> > Strcpy is inherently not safe, and strlcpy() should be used instead.
> > __trace_find_cmdline() uses strcpy() because the comms saved must have a
> > terminating nul character, but it doesn't hurt to add the extra protection
> > of using strlcpy() instead of strcpy().
> > 
> > Link: http://lkml.kernel.org/r/1493806274-13936-1-git-send-email-amit.pundir@linaro.org
> > 
> > Signed-off-by: Amey Telawane <ameyt@codeaurora.org>
> > [AmitP: Cherry-picked this commit from CodeAurora kernel/msm-3.10
> > https://source.codeaurora.org/quic/la/kernel/msm-3.10/commit/?id=2161ae9a70b12cf18ac8e5952a20161ffbccb477]
> > Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
> > [ Updated change log and removed the "- 1" from len parameter ]
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> FYI,
> 
> I never marked this for stable because there's nothing broken that it
> fixes. It's more of a "just in case". The "comm" passed in is allocated
> to be TASK_COMM_LEN, and is updated at creation using strlcpy() with
> TASK_COMM_LEN. It's the task->comm. It's used throughout the kernel. If
> it were ever to be bigger than TASK_COMM_LEN or not end with a '\0'
> there would be many other bugs, as task->comm is used throughout the
> kernel with assumptions that these two cases are always true.
> 
> I accepted the patch because it doesn't hurt. I'm fine if it goes to
> stable, but I find it rather redundant.

Hm, Amit asked me to merge all of these for some reason.  I guess people
see the "oh, look, strcpy is bad!" and jump to wrong conclusions.

{sigh}

Amit, can I drop these and you will not get upset?

thanks,

greg k-h