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 E47953DCDB8 for ; Tue, 21 Apr 2026 20:05:41 +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=1776801942; cv=none; b=HEu47kBVt4n/9F3YxHt6Hqqb+AGQyCT7JvBVqr76/R8surpdRsJzpjLIbnZACk7yKbVpLuiFT+vIUnZPX23bEbWDKYF+L+XpA8IjxejLj6er7wayzQMaskGeN0NgGDL5+ifawupR/Zfu4nJLYw0FMfMri4XhmOHEIl4IvGSr3Gc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776801942; c=relaxed/simple; bh=d5pHxM+6pWTTF9TOiK+sHjX4BXwc4rmKt0qC0IiMc28=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=ITUbAuV+gzzEqEFuyPab8rc91+JgFI6P76yUuyemL0mo7Hw+xA3zFb7ew8k0lBQxFGCsHz2ThRueivFUsdFC5K4tqO1BIcqvVbeAppQ2N36LzWGXGMmsuSZw6xTfCuGAi5q8qmAn126pzRSWaHIUpuCHtL72q98+Sz8S7cnu5AI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vE+MBl1v; 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="vE+MBl1v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB22AC2BCB0; Tue, 21 Apr 2026 20:05:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776801941; bh=d5pHxM+6pWTTF9TOiK+sHjX4BXwc4rmKt0qC0IiMc28=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=vE+MBl1vEeBWLdg5BxfI9c9Ufj2EoFe/Nz45FYft8Tw0CxAPa7DhpEWDcSxVVSqba JpDP6Reyc8sQ0websnzNfCHBCIKs/UIuofJK0aW7dU4gqsCfkySqdXT7jHQuRxbmzH jpcWJnwxbrJeil8MKZtjJLVzQ9O3fCNIYFKpUFPq7IDwKHLF3zC6J2b360mAgdPEeG Ows0c2bMb7dRhdnqykxBAY7i21xSv4roa7Pa2wm4HiCf2l3Pl4tcyICIRX1zLctgGi rf5n+Cg8fb2Wd1fLXt+27UPpktGwdmkkWRobrS07ARRZZdt3Tio4Qs6WeIAYpVpEeH uocVHL2jTZP1A== Message-ID: <5e27fcbff7ff788bf750482f5fb9ad607f30ac82.camel@kernel.org> Subject: Re: [PATCH] NFSD: Report whether fh_key was actually updated From: Jeff Layton To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: linux-nfs@vger.kernel.org, Chuck Lever , jaeyeong , Benjamin Coddington Date: Tue, 21 Apr 2026 16:05:37 -0400 In-Reply-To: <20260421192021.428052-1-cel@kernel.org> References: <20260421192021.428052-1-cel@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 YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf CBYyUE8QJpvTZyfUHNYldXlrjO6n5MdOempLqWpfOmcGkwnyNRBR46g/jf8KnPRwXs509yAqDB6sE LZH+yWr9LQZEwARAQABtCVKZWZmIExheXRvbiA8amxheXRvbkBwb29jaGllcmVkcy5uZXQ+iQI7BB MBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCTpXWPAIZAQAKCRAADmhBGVaCFc65D/4 gBLNMHopQYgG/9RIM3kgFCCQV0pLv0hcg1cjr+bPI5f1PzJoOVi9s0wBDHwp8+vtHgYhM54yt43uI 7Htij0RHFL5eFqoVT4TSfAg2qlvNemJEOY0e4daljjmZM7UtmpGs9NN0r9r50W82eb5Kw5bc/r0km R/arUS2st+ecRsCnwAOj6HiURwIgfDMHGPtSkoPpu3DDp/cjcYUg3HaOJuTjtGHFH963B+f+hyQ2B rQZBBE76ErgTDJ2Db9Ey0kw7VEZ4I2nnVUY9B5dE2pJFVO5HJBMp30fUGKvwaKqYCU2iAKxdmJXRI ONb7dSde8LqZahuunPDMZyMA5+mkQl7kpIpR6kVDIiqmxzRuPeiMP7O2FCUlS2DnJnRVrHmCljLkZ Wf7ZUA22wJpepBligemtSRSbqCyZ3B48zJ8g5B8xLEntPo/NknSJaYRvfEQqGxgk5kkNWMIMDkfQO lDSXZvoxqU9wFH/9jTv1/6p8dHeGM0BsbBLMqQaqnWiVt5mG92E1zkOW69LnoozE6Le+12DsNW7Rj iR5K+27MObjXEYIW7FIvNN/TQ6U1EOsdxwB8o//Yfc3p2QqPr5uS93SDDan5ehH59BnHpguTc27Xi QQZ9EGiieCUx6Zh2ze3X2UW9YNzE15uKwkkuEIj60NvQRmEDfweYfOfPVOueC+iFifbQgSmVmZiBM YXl0b24gPGpsYXl0b25AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6V0q0CGwMGCwkIBwMCBhUIAgkKC wQWAgMBAh4BAheAAAoJEAAOaEEZVoIViKUQALpvsacTMWWOd7SlPFzIYy2/fjvKlfB/Xs4YdNcf9q LqF+lk2RBUHdR/dGwZpvw/OLmnZ8TryDo2zXVJNWEEUFNc7wQpl3i78r6UU/GUY/RQmOgPhs3epQC 3PMJj4xFx+VuVcf/MXgDDdBUHaCTT793hyBeDbQuciARDJAW24Q1RCmjcwWIV/pgrlFa4lAXsmhoa c8UPc82Ijrs6ivlTweFf16VBc4nSLX5FB3ls7S5noRhm5/Zsd4PGPgIHgCZcPgkAnU1S/A/rSqf3F LpU+CbVBDvlVAnOq9gfNF+QiTlOHdZVIe4gEYAU3CUjbleywQqV02BKxPVM0C5/oVjMVx3bri75n1 TkBYGmqAXy9usCkHIsG5CBHmphv9MHmqMZQVsxvCzfnI5IO1+7MoloeeW/lxuyd0pU88dZsV/riHw 87i2GJUJtVlMl5IGBNFpqoNUoqmvRfEMeXhy/kUX4Xc03I1coZIgmwLmCSXwx9MaCPFzV/dOOrju2 xjO+2sYyB5BNtxRqUEyXglpujFZqJxxau7E0eXoYgoY9gtFGsspzFkVNntamVXEWVVgzJJr/EWW0y +jNd54MfPRqH+eCGuqlnNLktSAVz1MvVRY1dxUltSlDZT7P2bUoMorIPu8p7ZCg9dyX1+9T6Muc5d Hxf/BBP/ir+3e8JTFQBFOiLNdFtB9KZWZmIExheXRvbiA8amxheXRvbkBzYW1iYS5vcmc+iQI4BBM BAgAiBQJOldK9AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAADmhBGVaCFWgWD/0ZRi4h N9FK2BdQs9RwNnFZUr7JidAWfCrs37XrA/56olQl3ojn0fQtrP4DbTmCuh0SfMijB24psy1GnkPep naQ6VRf7Dxg/Y8muZELSOtsv2CKt3/02J1BBitrkkqmHyni5fLLYYg6fub0T/8Kwo1qGPdu1hx2BQ RERYtQ/S5d/T0cACdlzi6w8rs5f09hU9Tu4qV1JLKmBTgUWKN969HPRkxiojLQziHVyM/weR5Reu6 FZVNuVBGqBD+sfk/c98VJHjsQhYJijcsmgMb1NohAzwrBKcSGKOWJToGEO/1RkIN8tqGnYNp2G+aR 685D0chgTl1WzPRM6mFG1+n2b2RR95DxumKVpwBwdLPoCkI24JkeDJ7lXSe3uFWISstFGt0HL8Eew P8RuGC8s5h7Ct91HMNQTbjgA+Vi1foWUVXpEintAKgoywaIDlJfTZIl6Ew8ETN/7DLy8bXYgq0Xzh aKg3CnOUuGQV5/nl4OAX/3jocT5Cz/OtAiNYj5mLPeL5z2ZszjoCAH6caqsF2oLyAnLqRgDgR+wTQ T6gMhr2IRsl+cp8gPHBwQ4uZMb+X00c/Amm9VfviT+BI7B66cnC7Zv6Gvmtu2rEjWDGWPqUgccB7h dMKnKDthkA227/82tYoFiFMb/NwtgGrn5n2vwJyKN6SEoygGrNt0SI84y6hEVbQlSmVmZiBMYXl0b 24gPGpsYXl0b25AcHJpbWFyeWRhdGEuY29tPokCOQQTAQIAIwUCU4xmKQIbAwcLCQgHAwIBBhUIAg kKCwQWAgMBAh4BAheAAAoJEAAOaEEZVoIV1H0P/j4OUTwFd7BBbpoSp695qb6HqCzWMuExsp8nZjr uymMaeZbGr3OWMNEXRI1FWNHMtcMHWLP/RaDqCJil28proO+PQ/yPhsr2QqJcW4nr91tBrv/MqItu AXLYlsgXqp4BxLP67bzRJ1Bd2x0bWXurpEXY//VBOLnODqThGEcL7jouwjmnRh9FTKZfBDpFRaEfD FOXIfAkMKBa/c9TQwRpx2DPsl3eFWVCNuNGKeGsirLqCxUg5kWTxEorROppz9oU4HPicL6rRH22Ce 6nOAON2vHvhkUuO3GbffhrcsPD4DaYup4ic+DxWm+DaSSRJ+e1yJvwi6NmQ9P9UAuLG93S2MdNNbo sZ9P8k2mTOVKMc+GooI9Ve/vH8unwitwo7ORMVXhJeU6Q0X7zf3SjwDq2lBhn1DSuTsn2DbsNTiDv qrAaCvbsTsw+SZRwF85eG67eAwouYk+dnKmp1q57LDKMyzysij2oDKbcBlwB/TeX16p8+LxECv51a sjS9TInnipssssUDrHIvoTTXWcz7Y5wIngxDFwT8rPY3EggzLGfK5Zx2Q5S/N0FfmADmKknG/D8qG IcJE574D956tiUDKN4I+/g125ORR1v7bP+OIaayAvq17RP+qcAqkxc0x8iCYVCYDouDyNvWPGRhbL UO7mlBpjW9jK9e2fvZY9iw3QzIPGKtClKZWZmIExheXRvbiA8amVmZi5sYXl0b25AcHJpbWFyeWRh dGEuY29tPokCOQQTAQIAIwUCU4xmUAIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEAAOa EEZVoIVzJoQALFCS6n/FHQS+hIzHIb56JbokhK0AFqoLVzLKzrnaeXhE5isWcVg0eoV2oTScIwUSU apy94if69tnUo4Q7YNt8/6yFM6hwZAxFjOXR0ciGE3Q+Z1zi49Ox51yjGMQGxlakV9ep4sV/d5a50 M+LFTmYSAFp6HY23JN9PkjVJC4PUv5DYRbOZ6Y1+TfXKBAewMVqtwT1Y+LPlfmI8dbbbuUX/kKZ5d dhV2736fgyfpslvJKYl0YifUOVy4D1G/oSycyHkJG78OvX4JKcf2kKzVvg7/Rnv+AueCfFQ6nGwPn 0P91I7TEOC4XfZ6a1K3uTp4fPPs1Wn75X7K8lzJP/p8lme40uqwAyBjk+IA5VGd+CVRiyJTpGZwA0 jwSYLyXboX+Dqm9pSYzmC9+/AE7lIgpWj+3iNisp1SWtHc4pdtQ5EU2SEz8yKvDbD0lNDbv4ljI7e flPsvN6vOrxz24mCliEco5DwhpaaSnzWnbAPXhQDWb/lUgs/JNk8dtwmvWnqCwRqElMLVisAbJmC0 BhZ/Ab4sph3EaiZfdXKhiQqSGdK4La3OTJOJYZphPdGgnkvDV9Pl1QZ0ijXQrVIy3zd6VCNaKYq7B AKidn5g/2Q8oio9Tf4XfdZ9dtwcB+bwDJFgvvDYaZ5bI3ln4V3EyW5i2NfXazz/GA/I/ZtbsigCFc 8ftCBKZWZmIExheXRvbiA8amxheXRvbkBrZXJuZWwub3JnPokCOAQTAQIAIgUCWe8u6AIbAwYLCQg HAwIGFQgCCQoLBBYCAwECHgECF4AACgkQAA5oQRlWghUuCg/+Lb/xGxZD2Q1oJVAE37uW308UpVSD 2tAMJUvFTdDbfe3zKlPDTuVsyNsALBGclPLagJ5ZTP+Vp2irAN9uwBuacBOTtmOdz4ZN2tdvNgozz uxp4CHBDVzAslUi2idy+xpsp47DWPxYFIRP3M8QG/aNW052LaPc0cedYxp8+9eiVUNpxF4SiU4i9J DfX/sn9XcfoVZIxMpCRE750zvJvcCUz9HojsrMQ1NFc7MFT1z3MOW2/RlzPcog7xvR5ENPH19ojRD CHqumUHRry+RF0lH00clzX/W8OrQJZtoBPXv9ahka/Vp7kEulcBJr1cH5Wz/WprhsIM7U9pse1f1g Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-04-21 at 15:20 -0400, Chuck Lever wrote: > From: Chuck Lever >=20 > The nfsd_ctl_fh_key_set tracepoint was introduced to capture > operator activity on the filehandle signing key. Earlier revisions > logged the key bytes verbatim; the version that landed hashes the > 16 key bytes through crc32_le and stores the result. >=20 > CRC32 is a linear projection of its input rather than a one-way > function, and truncating any hash of fixed-size secret material > leaves the key recoverable under offline brute force when the > threat model includes an attacker with access to the trace ring. >=20 > The operational question the fingerprint was meant to answer is > whether a NFSD_CMD_THREADS_SET call that carries an > NFSD_A_SERVER_FH_KEY attribute actually replaced the active key or > re-installed the value already in place. Answer that question > directly: compare the incoming key bytes against the current > nn->fh_key inside nfsd_nl_fh_key_set() and surface a single bit to > the tracepoint. The event now prints "updated" when the stored > key changed and "unmodified" otherwise. A first set that fails > kmalloc reports "unmodified" because no key was installed. >=20 > Reported-by: jaeyeong > Fixes: 62346217fd72 ("NFSD: Add a key for signing filehandles") > Cc: Benjamin Coddington > Signed-off-by: Chuck Lever > --- > fs/nfsd/nfsctl.c | 18 ++++++++++++++---- > fs/nfsd/trace.h | 16 +++++++--------- > 2 files changed, 21 insertions(+), 13 deletions(-) >=20 > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c > index c76849f316f7..064a2e749bc9 100644 > --- a/fs/nfsd/nfsctl.c > +++ b/fs/nfsd/nfsctl.c > @@ -1610,16 +1610,27 @@ int nfsd_nl_rpc_status_get_dumpit(struct sk_buff = *skb, > static int nfsd_nl_fh_key_set(const struct nlattr *attr, struct nfsd_net= *nn) > { > siphash_key_t *fh_key =3D nn->fh_key; > + u64 k0, k1; > + bool changed; > + > + k0 =3D get_unaligned_le64(nla_data(attr)); > + k1 =3D get_unaligned_le64(nla_data(attr) + 8); > =20 > if (!fh_key) { > fh_key =3D kmalloc(sizeof(siphash_key_t), GFP_KERNEL); > - if (!fh_key) > + if (!fh_key) { > + trace_nfsd_ctl_fh_key_set(false, -ENOMEM); > return -ENOMEM; > + } > nn->fh_key =3D fh_key; > + changed =3D true; > + } else { > + changed =3D fh_key->key[0] !=3D k0 || fh_key->key[1] !=3D k1; > } > =20 > - fh_key->key[0] =3D get_unaligned_le64(nla_data(attr)); > - fh_key->key[1] =3D get_unaligned_le64(nla_data(attr) + 8); > + fh_key->key[0] =3D k0; > + fh_key->key[1] =3D k1; > + trace_nfsd_ctl_fh_key_set(changed, 0); > return 0; > } > =20 > @@ -1698,7 +1709,6 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, s= truct genl_info *info) > attr =3D info->attrs[NFSD_A_SERVER_FH_KEY]; > if (attr) { > ret =3D nfsd_nl_fh_key_set(attr, nn); > - trace_nfsd_ctl_fh_key_set((const char *)nn->fh_key, ret); > if (ret) > goto out_unlock; > } > diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h > index a13d18447324..1c5a1e50f946 100644 > --- a/fs/nfsd/trace.h > +++ b/fs/nfsd/trace.h > @@ -2263,23 +2263,21 @@ TRACE_EVENT(nfsd_end_grace, > =20 > TRACE_EVENT(nfsd_ctl_fh_key_set, > TP_PROTO( > - const char *key, > + bool changed, > int result > ), > - TP_ARGS(key, result), > + TP_ARGS(changed, result), > TP_STRUCT__entry( > - __field(u32, key_hash) > + __field(bool, changed) > __field(int, result) > ), > TP_fast_assign( > - if (key) > - __entry->key_hash =3D ~crc32_le(0xFFFFFFFF, key, 16); > - else > - __entry->key_hash =3D 0; > + __entry->changed =3D changed; > __entry->result =3D result; > ), > - TP_printk("key=3D0x%08x result=3D%d", > - __entry->key_hash, __entry->result > + TP_printk("key %s, result=3D%d", > + __entry->changed ? "updated" : "unmodified", > + __entry->result > ) > ); > =20 Reviewed-by: Jeff Layton