From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A7552374758; Wed, 27 May 2026 19:27:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779910072; cv=none; b=R6brYiJ+6jPPlcM/Z1mxF+rQ59MKv3QHgvQV7PKrko2g/N8rjZi2TmhACcrVMad9tWFVa9/Scx3ztQ6gwnKWGAaK31cFIdQe43FliOnJKro7mcBXhZHDgHQ4dx8ye+0TW5InPzOo+RdvmCdVtu4AwDPDuv5+KTTyu6qAOlT5Xmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779910072; c=relaxed/simple; bh=CS9fp06tgJFFM/VUFAtYTchdbDmY3b91rtzzms6B1wo=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=lKidrCECb4NdPJrlztgmFsuKvDZcgl+rzlFsGsjEgdQ1yFECimygNDxAm0U2QpxhrbvqW7PVdZdhCJ28eNYoGP6bwio65A7PfReYP+mLkcM9XZLfDuZ60e0H8DaBk77sjmyM26gkkP4+EeapSt3WaNRsSoi6VJWhkvBbzZB+1js= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LpgsHTi/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LpgsHTi/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B1F91F00A3D; Wed, 27 May 2026 19:27:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779910071; bh=gvCxMDgesggPL+JgfW4wgQm3SgsAAMteMXQhuNP0Yt0=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=LpgsHTi/gKpl3GnJfpkQDbEjjueP15F1UI4uQ7sNe6XHckF7CIo4tz10zAqw46aCS 2G/5sCx6jYPNtzxTRbkpLdwA99eg+Uo17tEgDetYv2kd+COllK+aJfDHdnW12W+VyY CqENX/XYU1zscp+3dr0PQBe2+0TNul4XC3ryLqH6G03GSrBrhHLC4eqB+nZp1roDHF 1q03W+M5YrbPtvAOTrfvfGnSjz90loYYB7PLjBV5LKLsr5i3IrBg5g055jjkrig8JN X0e7YPAoPn1icF0f9ejK7ZvIIs24j0cq+24iyRaePQLe12OZ+G6DU9REVzQUTL7V+4 UocPm7gWnmVVA== Message-ID: Subject: Re: [PATCH] nfsd: fix XDR padding calculation in ff_encode_getdeviceinfo From: Jeff Layton To: Chuck Lever , Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Sasha Levin Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 27 May 2026 15:27:49 -0400 In-Reply-To: References: <20260527-pnfs-fixes-v1-1-784f39dc1eca@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV 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the da_addr_body reservation > > as 16 + netid_len + addr_len, but the subsequent xdr_encode_opaque() > > calls emit 8 + round_up(netid_len, 4) + round_up(addr_len, 4) bytes. > > The mismatch means the declared da_addr_body length exceeds the actual > > encoded data by 2-8 bytes on every flexfile GETDEVICEINFO reply, > > leaking stale reply-page content to the client and mis-aligning the > > subsequent version list decode. > >=20 > > Use xdr_align_size() for each string length to match what > > xdr_encode_opaque() actually writes. > >=20 > > Fixes: efcae97fa425 ("NFSD: da_addr_body field missing in some=20 > > GETDEVICEINFO replies") > > Assisted-by: kres:claude-opus-4-6 > > Signed-off-by: Jeff Layton > > --- > > fs/nfsd/flexfilelayoutxdr.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > >=20 > > diff --git a/fs/nfsd/flexfilelayoutxdr.c b/fs/nfsd/flexfilelayoutxdr.c > > index f9f7e38cba13..7f357dbd1bb1 100644 > > --- a/fs/nfsd/flexfilelayoutxdr.c > > +++ b/fs/nfsd/flexfilelayoutxdr.c > > @@ -94,7 +94,8 @@ nfsd4_ff_encode_getdeviceinfo(struct xdr_stream *xdr, > > } > >=20 > > /* len + padding for two strings */ > > - addr_len =3D 16 + da->netaddr.netid_len + da->netaddr.addr_len; > > + addr_len =3D 8 + xdr_align_size(da->netaddr.netid_len) + > > + xdr_align_size(da->netaddr.addr_len); > > ver_len =3D 20; > >=20 > > len =3D 4 + ver_len + 4 + addr_len; > >=20 > > --- > > base-commit: b69fc3eaa867d0caa904634ea7a1b4569411b163 > > change-id: 20260527-pnfs-fixes-23451bb03d57 > >=20 > > Best regards, > > --=20 > > Jeff Layton >=20 > Fixes tag might/should be 9b9960a0ca47 ? LLM reviews vary on this. >=20 > nfsd4_ff_encode_layoutget at fs/nfsd/flexfilelayoutxdr.c:40-41 has the > same unaligned pattern for UID/GID strings: 8 + uid.len + 8 + gid.len. > Do you intend to address that calculation as well? >=20 > My preference here is to convert to xdrgen instead, but that's a much > bigger and less back-portable change. >=20 Yep, I just saw the Sashiko review for it. I'll fix that one up in a separate patch. Cheers, --=20 Jeff Layton