From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 093F9205ABA for ; Mon, 29 Sep 2025 17:39:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759167563; cv=none; b=Bl3osMRTqi+rZAeTtpTLOWVDjxXLQG4q+pT0RMJ47RiCQRaopvVP6Yns+XOeprjW7rJR+9lkLbokPfhHnrI2E7kCofsXOI9vCG5KmeeQLeWEshvnYjd3FhLJD/uUH3DCe2IhBpr2zE2wdIdymyoYi0XjRItFV8fnBmf4SPM/lAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759167563; c=relaxed/simple; bh=/IZvAAZ+Vojcj/uxScKX3xbsyX09gmQvRpCR1HtcppM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fmxKR7TQs5hB7Olgkx+h7QGf+YOnvHbDVquIwTRGlnuuvo9hwTJ4QfSkbc3or0eL95n/dXxGUKfV8VWtUTYRKQCSh09WZwJr+5/3cVOkrRRJ/TV6YJaz+gQmCT5/fa49hL5b4OmDyKZEbR/ql3FIcMh2glgRz3B8Qyqgf5chkao= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mvPIc/bS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mvPIc/bS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D7F3C4CEF4; Mon, 29 Sep 2025 17:39:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759167560; bh=/IZvAAZ+Vojcj/uxScKX3xbsyX09gmQvRpCR1HtcppM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mvPIc/bSvXQ5dJEHgXu8lNZCWmkkWMrKWmGXhnY5f5WYGvk5SWsMZJ3CW4ufRPWT6 kn9wO2FZZv9Es6VruZZfoqMHg766dOR/7ooraXbLHi1AYh3J8JWGklIWPUrZgjrJon X7fViafp5JgNl8VvARwOmqTcZwD/5yMORYkWi23DYmEKDObtrgN3n6Ko8oMYZ9t5N0 Oy9DUCZ37eAx9DIghsuGbCF78NqbHR4whjbnDAJFURlBqz0Yr95jcmU+h0/lhxpHmJ vRAit2/9+K8vCKtM3sZ0GM8cax587NUddx6egqc8t/n/JJrpW64J+kPgnh0CGFaHs5 MpACX5pakk+rQ== Date: Mon, 29 Sep 2025 13:39:19 -0400 From: Mike Snitzer To: Chuck Lever Cc: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, Chuck Lever Subject: Re: [PATCH v5 5/6] NFSD: Prevent a NULL pointer dereference in fh_getattr() Message-ID: References: <20250929155646.4818-1-cel@kernel.org> <20250929155646.4818-6-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250929155646.4818-6-cel@kernel.org> On Mon, Sep 29, 2025 at 11:56:45AM -0400, Chuck Lever wrote: > From: Chuck Lever > > In general, fh_getattr() can be called after the target dentry has > gone negative. For a negative dentry, d_inode(p.dentry) will return > NULL. S_ISREG() will dereference that pointer. > > Avoid this potential regression by using the d_is_reg() helper > instead. > > Suggested-by: NeilBrown > Fixes: bc70aaeba7df ("NFSD: filecache: add STATX_DIOALIGN and STATX_DIO_READ_ALIGN support") > Signed-off-by: Chuck Lever > --- > fs/nfsd/nfsfh.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c > index ed85dd43da18..16182936828f 100644 > --- a/fs/nfsd/nfsfh.c > +++ b/fs/nfsd/nfsfh.c > @@ -696,10 +696,9 @@ __be32 fh_getattr(const struct svc_fh *fhp, struct kstat *stat) > .mnt = fhp->fh_export->ex_path.mnt, > .dentry = fhp->fh_dentry, > }; > - struct inode *inode = d_inode(p.dentry); > u32 request_mask = STATX_BASIC_STATS; > > - if (S_ISREG(inode->i_mode)) > + if (d_is_reg(p.dentry)) > request_mask |= (STATX_DIOALIGN | STATX_DIO_READ_ALIGN); > > if (fhp->fh_maxsize == NFS4_FHSIZE) > -- > 2.51.0 > > Reviewed-by: Mike Snitzer