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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Azeem Shaikh' <azeemshaikh38@gmail.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@kernel.org>
CC:     "linux-hardening@vger.kernel.org" <linux-hardening@vger.kernel.org>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v3] NFSD: Remove open coding of string copy
Thread-Topic: [PATCH v3] NFSD: Remove open coding of string copy
Thread-Index: AQHZhtarLR7mMXSOG0mD9inDFwvZGq9cpMAQ
Date:   Tue, 16 May 2023 09:33:58 +0000
Message-ID: <d48a166d1cbc477f9cf063e91f7b3005@AcuMS.aculab.com>
References: <20230515024044.2677124-1-azeemshaikh38@gmail.com>
In-Reply-To: <20230515024044.2677124-1-azeemshaikh38@gmail.com>
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From: Azeem Shaikh
> Sent: 15 May 2023 03:41
> 
> Instead of open coding a __dynamic_array(), use the __string() and
> __assign_str() helper macros that exist for this kind of use case.

Is this actually a dynamic array, or just a char[8] ?
On 64 bit copying a short fixed-length string is far better
than any kind of dynamic sized allocation.

	David

> 
> Part of an effort to remove deprecated strlcpy() [1] completely from the
> kernel[2].
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Fixes: 3c92fba557c6 ("NFSD: Enhance the nfsd_cb_setup tracepoint")
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> ---
>  fs/nfsd/trace.h |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index 4183819ea082..72a906a053dc 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -1365,19 +1365,19 @@ TRACE_EVENT(nfsd_cb_setup,
>  		__field(u32, cl_id)
>  		__field(unsigned long, authflavor)
>  		__sockaddr(addr, clp->cl_cb_conn.cb_addrlen)
> -		__array(unsigned char, netid, 8)
> +		__string(netid, netid)
>  	),
>  	TP_fast_assign(
>  		__entry->cl_boot = clp->cl_clientid.cl_boot;
>  		__entry->cl_id = clp->cl_clientid.cl_id;
> -		strlcpy(__entry->netid, netid, sizeof(__entry->netid));
> +		__assign_str(netid, netid);
>  		__entry->authflavor = authflavor;
>  		__assign_sockaddr(addr, &clp->cl_cb_conn.cb_addr,
>  				  clp->cl_cb_conn.cb_addrlen)
>  	),
>  	TP_printk("addr=%pISpc client %08x:%08x proto=%s flavor=%s",
>  		__get_sockaddr(addr), __entry->cl_boot, __entry->cl_id,
> -		__entry->netid, show_nfsd_authflavor(__entry->authflavor))
> +		__get_str(netid), show_nfsd_authflavor(__entry->authflavor))
>  );
> 
>  TRACE_EVENT(nfsd_cb_setup_err,
> --
> 2.40.1.606.ga4b1b128d6-goog
> 

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