From 24d92de9186ebc340687caf7356e1070773e67bc Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Thu, 15 Feb 2024 20:24:51 -0500
Subject: [PATCH] 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 <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
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 b78eceebd945e..dfcc957e460d6 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 f32128955ec8d..a7a07470c1f84 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 2f524f4535082..2927b1263f086 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1171,8 +1171,7 @@ 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 7476726634f53..aee12adf05981 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5460,7 +5460,7 @@ 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 a7315928a7607..36370b957b633 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 76e89329b9f11..a3a4400e75be1 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -476,7 +476,6 @@ 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
@@ -488,8 +487,7 @@ 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;
@@ -538,9 +536,6 @@ 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
@@ -558,6 +553,16 @@ 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;
@@ -585,6 +590,7 @@ 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);
@@ -1411,7 +1417,7 @@ 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 1efa4e8dfb034..c60fdb6200fde 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 03fe4e21306cb..522067b7fd755 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 {
--
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