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 A3D6A3148B2; Thu, 8 Jan 2026 19:10:07 +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=1767899407; cv=none; b=MSNtMRc+ck26JAnGcSf0Fw8X7OhYUQxG+HeHQITVCYDUykCZrGrcuyqLhBAk/TfGEBsye3TFpOHMrj489/4NaT303iItCA6Ox/gdmsMi2xzA/SOu+cDCKhnromGVlFmhY8MpCJ679LJ+ZnuHnwwBsEiQYmTv9P8Hk9HteIA+SVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767899407; c=relaxed/simple; bh=CM1RJh917k7L4mUGMpZUiQwvjPlDvdh3fX3hN8q/nW8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ii6e70ljYP4ycHDdV7uBU300IYnkKQBcht2VtjxMzmqPY8jDql3k2lzXeqZejhEv5shAjswicDV0AruSoMeRe2fs6mxaXetuzWWrwl9feo20LTazvFVtAp1Knt3bAcM9378IJy3Xofs7bylrNSlM5ZmdqTlBgsHrs0lWaSVXKI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lTjZHGOW; 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="lTjZHGOW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C066CC19423; Thu, 8 Jan 2026 19:10:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767899407; bh=CM1RJh917k7L4mUGMpZUiQwvjPlDvdh3fX3hN8q/nW8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lTjZHGOWmYgVStAv8ZQrKAW3Q3wcaXiQ+vh5cCVOKkTpQoN9laVmScfpIUAGfSilP vXZxyYaS4IViduf0EKDOymbHiKULT1TqTwdorZvIMAoDbBcmmUkx4iRdHqKRL51+rr Gm0En1yHVJ7Ly/rA2Z5Cd6tMBIUjBqKy3XSuEhvpgBvUz4Gj9JZ+RelFggNH6u3wUv WcWo1l47D8XIg8MxBCaMeM3dIYpFJ8M8vuRvTzHaErY1KgrHo4tiz27Uq1kT7ylWZR 9Ruj1DZEMGYF3xEasGB8vVzobbia8cq1fgvxpRP32EXbbG4Ek+aC9mPsDBOY7TTr+b kiGCWjUZXDEIQ== From: Chuck Lever To: Cc: Greg Kroah-Hartman , Sasha Levin , , Trond Myklebust , Jeff Layton , NeilBrown Subject: [PATCH 6.6.y v2 2/4] nfsd: Fix NFSv3 atomicity bugs in nfsd_setattr() Date: Thu, 8 Jan 2026 14:10:00 -0500 Message-ID: <20260108191002.4071603-3-cel@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <2025122941-civic-revered-b250@gregkh> References: <2025122941-civic-revered-b250@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Trond Myklebust [ Upstream commit 24d92de9186ebc340687caf7356e1070773e67bc ] nfsd: Fix NFSv3 atomicity bugs in nfsd_setattr() The main point of the guarded SETATTR is to prevent races with other WRITE and SETATTR calls. That requires that the check of the guard time against the inode ctime be done after taking the inode lock. Furthermore, we need to take into account the 32-bit nature of timestamps in NFSv3, and the possibility that files may change at a faster rate than once a second. Signed-off-by: Trond Myklebust Reviewed-by: Jeff Layton Reviewed-by: NeilBrown Stable-dep-of: 442d27ff09a2 ("nfsd: set security label during create operations") Signed-off-by: Chuck Lever --- fs/nfsd/nfs3proc.c | 6 ++++-- fs/nfsd/nfs3xdr.c | 5 +---- fs/nfsd/nfs4proc.c | 3 +-- fs/nfsd/nfs4state.c | 2 +- fs/nfsd/nfsproc.c | 6 +++--- fs/nfsd/vfs.c | 20 +++++++++++++------- fs/nfsd/vfs.h | 2 +- fs/nfsd/xdr3.h | 2 +- 8 files changed, 25 insertions(+), 21 deletions(-) diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c index 666bad8182e5..f4ccbb1f49ba 100644 --- a/fs/nfsd/nfs3proc.c +++ b/fs/nfsd/nfs3proc.c @@ -71,13 +71,15 @@ nfsd3_proc_setattr(struct svc_rqst *rqstp) struct nfsd_attrs attrs = { .na_iattr = &argp->attrs, }; + const struct timespec64 *guardtime = NULL; dprintk("nfsd: SETATTR(3) %s\n", SVCFH_fmt(&argp->fh)); fh_copy(&resp->fh, &argp->fh); - resp->status = nfsd_setattr(rqstp, &resp->fh, &attrs, - argp->check_guard, argp->guardtime); + if (argp->check_guard) + guardtime = &argp->guardtime; + resp->status = nfsd_setattr(rqstp, &resp->fh, &attrs, guardtime); return rpc_success; } diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index f32128955ec8..a7a07470c1f8 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -295,17 +295,14 @@ svcxdr_decode_sattr3(struct svc_rqst *rqstp, struct xdr_stream *xdr, static bool svcxdr_decode_sattrguard3(struct xdr_stream *xdr, struct nfsd3_sattrargs *args) { - __be32 *p; u32 check; if (xdr_stream_decode_bool(xdr, &check) < 0) return false; if (check) { - p = xdr_inline_decode(xdr, XDR_UNIT * 2); - if (!p) + if (!svcxdr_decode_nfstime3(xdr, &args->guardtime)) return false; args->check_guard = 1; - args->guardtime = be32_to_cpup(p); } else args->check_guard = 0; diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 37b918e4a53d..c9ae789bb045 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1160,8 +1160,7 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, goto out; save_no_wcc = cstate->current_fh.fh_no_wcc; cstate->current_fh.fh_no_wcc = true; - status = nfsd_setattr(rqstp, &cstate->current_fh, &attrs, - 0, (time64_t)0); + status = nfsd_setattr(rqstp, &cstate->current_fh, &attrs, NULL); cstate->current_fh.fh_no_wcc = save_no_wcc; if (!status) status = nfserrno(attrs.na_labelerr); diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 57f1f6aa19c9..511fedc37008 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -5223,7 +5223,7 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh, return 0; if (!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE)) return nfserr_inval; - return nfsd_setattr(rqstp, fh, &attrs, 0, (time64_t)0); + return nfsd_setattr(rqstp, fh, &attrs, NULL); } static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp, diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index a7315928a760..36370b957b63 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -103,7 +103,7 @@ nfsd_proc_setattr(struct svc_rqst *rqstp) } } - resp->status = nfsd_setattr(rqstp, fhp, &attrs, 0, (time64_t)0); + resp->status = nfsd_setattr(rqstp, fhp, &attrs, NULL); if (resp->status != nfs_ok) goto out; @@ -390,8 +390,8 @@ nfsd_proc_create(struct svc_rqst *rqstp) */ attr->ia_valid &= ATTR_SIZE; if (attr->ia_valid) - resp->status = nfsd_setattr(rqstp, newfhp, &attrs, 0, - (time64_t)0); + resp->status = nfsd_setattr(rqstp, newfhp, &attrs, + NULL); } out_unlock: diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 1faf65147223..51c2ad3847c4 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -459,7 +459,6 @@ static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap) * @rqstp: controlling RPC transaction * @fhp: filehandle of target * @attr: attributes to set - * @check_guard: set to 1 if guardtime is a valid timestamp * @guardtime: do not act if ctime.tv_sec does not match this timestamp * * This call may adjust the contents of @attr (in particular, this @@ -471,8 +470,7 @@ static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap) */ __be32 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, - struct nfsd_attrs *attr, - int check_guard, time64_t guardtime) + struct nfsd_attrs *attr, const struct timespec64 *guardtime) { struct dentry *dentry; struct inode *inode; @@ -521,9 +519,6 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, nfsd_sanitize_attrs(inode, iap); - if (check_guard && guardtime != inode_get_ctime_sec(inode)) - return nfserr_notsync; - /* * The size case is special, it changes the file in addition to the * attributes, and file systems don't expect it to be mixed with @@ -541,6 +536,16 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, err = fh_fill_pre_attrs(fhp); if (err) goto out_unlock; + + if (guardtime) { + struct timespec64 ctime = inode_get_ctime(inode); + if ((u32)guardtime->tv_sec != (u32)ctime.tv_sec || + guardtime->tv_nsec != ctime.tv_nsec) { + err = nfserr_notsync; + goto out_fill_attrs; + } + } + for (retries = 1;;) { struct iattr attrs; @@ -568,6 +573,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, attr->na_aclerr = set_posix_acl(&nop_mnt_idmap, dentry, ACL_TYPE_DEFAULT, attr->na_dpacl); +out_fill_attrs: fh_fill_post_attrs(fhp); out_unlock: inode_unlock(inode); @@ -1374,7 +1380,7 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, * if the attributes have not changed. */ if (iap->ia_valid) - status = nfsd_setattr(rqstp, resfhp, attrs, 0, (time64_t)0); + status = nfsd_setattr(rqstp, resfhp, attrs, NULL); else status = nfserrno(commit_metadata(resfhp)); diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index e3c29596f4df..b476028e020b 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -69,7 +69,7 @@ __be32 nfsd_lookup_dentry(struct svc_rqst *, struct svc_fh *, const char *, unsigned int, struct svc_export **, struct dentry **); __be32 nfsd_setattr(struct svc_rqst *, struct svc_fh *, - struct nfsd_attrs *, int, time64_t); + struct nfsd_attrs *, const struct timespec64 *); int nfsd_mountpoint(struct dentry *, struct svc_export *); #ifdef CONFIG_NFSD_V4 __be32 nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *, diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h index 03fe4e21306c..522067b7fd75 100644 --- a/fs/nfsd/xdr3.h +++ b/fs/nfsd/xdr3.h @@ -14,7 +14,7 @@ struct nfsd3_sattrargs { struct svc_fh fh; struct iattr attrs; int check_guard; - time64_t guardtime; + struct timespec64 guardtime; }; struct nfsd3_diropargs { -- 2.52.0