Re: [PATCH] NFSv4.2: Fix file creating with O_EXCL get a bad mode

[bfields@fieldses.org (J. Bruce Fields)]

On Sat, Jan 07, 2017 at 10:45:47PM +0800, Kinglong Mee wrote:
> Acorrding to Matthieu Herrb's test cases, a new created file will
> get a bad mode as 0666 (expected 0644) after commit dff25ddb4808
> "nfs: add support for the umask attribute".
> 
> It is caused by missing check of FATTR4_WORD2_MODE_UMASK
> in nfs4_exclusive_attrset.

I don't understand:

> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 6dcbc5d..a3e9ef1 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -2697,7 +2697,8 @@ static inline void nfs4_exclusive_attrset(struct nfs4_opendata *opendata,
>  		sattr->ia_valid |= ATTR_MTIME;
>  
>  	/* Except MODE, it seems harmless of setting twice. */
> -	if ((attrset[1] & FATTR4_WORD1_MODE))
> +	if ((attrset[1] & FATTR4_WORD1_MODE) ||
> +	    (attrset[2] & FATTR4_WORD2_MODE_UMASK))
>  		sattr->ia_valid &= ~ATTR_MODE;

If I'm understanding this function correctly, attrset is the set of
attributes which the server tells us were used to store the verifier.

But mode_umask would never be a sensible place to store the
verifier, so if the server's response really says that then something's
wrong.

We should probably look at a network trace.

--b.

>  
>  	if (attrset[2] & FATTR4_WORD2_SECURITY_LABEL)
> -- 
> 2.9.3
> 
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