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authorTrond Myklebust <trond.myklebust@primarydata.com>2017-11-03 08:00:11 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-05 11:22:52 +0100
commitbd249dd078272e8cef53b98a73c1cdd60c532251 (patch)
tree9428559a79b7093198fd7b75c9c1fb8fc4a68cd6
parent54298082dbacba2591b2aa461320f31946cdbffb (diff)
nfsd: Fix another OPEN stateid race
commit d8a1a000555ecd1b824ac1ed6df8fe364dfbbbb0 upstream. If nfsd4_process_open2() is initialising a new stateid, and yet the call to nfs4_get_vfs_file() fails for some reason, then we must declare the stateid closed, and unhash it before dropping the mutex. Right now, we unhash the stateid after dropping the mutex, and without changing the stateid type, meaning that another OPEN could theoretically look it up and attempt to use it. Reported-by: Andrew W Elble <aweits@rit.edu> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/nfsd/nfs4state.c28
1 files changed, 13 insertions, 15 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3bf086aca5c0..11c67e8b939d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4319,6 +4319,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
struct nfs4_ol_stateid *stp = NULL;
struct nfs4_delegation *dp = NULL;
__be32 status;
+ bool new_stp = false;
/*
* Lookup file; if found, lookup stateid and check open request,
@@ -4338,11 +4339,19 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
goto out;
}
+ if (!stp) {
+ stp = init_open_stateid(fp, open);
+ if (!open->op_stp)
+ new_stp = true;
+ }
+
/*
* OPEN the file, or upgrade an existing OPEN.
* If truncate fails, the OPEN fails.
+ *
+ * stp is already locked.
*/
- if (stp) {
+ if (!new_stp) {
/* Stateid was found, this is an OPEN upgrade */
status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open);
if (status) {
@@ -4350,22 +4359,11 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
goto out;
}
} else {
- /* stp is returned locked. */
- stp = init_open_stateid(fp, open);
- /* See if we lost the race to some other thread */
- if (stp->st_access_bmap != 0) {
- status = nfs4_upgrade_open(rqstp, fp, current_fh,
- stp, open);
- if (status) {
- mutex_unlock(&stp->st_mutex);
- goto out;
- }
- goto upgrade_out;
- }
status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open);
if (status) {
- mutex_unlock(&stp->st_mutex);
+ stp->st_stid.sc_type = NFS4_CLOSED_STID;
release_open_stateid(stp);
+ mutex_unlock(&stp->st_mutex);
goto out;
}
@@ -4374,7 +4372,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
if (stp->st_clnt_odstate == open->op_odstate)
open->op_odstate = NULL;
}
-upgrade_out:
+
nfs4_inc_and_copy_stateid(&open->op_stateid, &stp->st_stid);
mutex_unlock(&stp->st_mutex);