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authorTrond Myklebust <trond.myklebust@primarydata.com>2017-11-03 08:00:11 -0400
committerJ. Bruce Fields <bfields@redhat.com>2017-11-27 16:45:10 -0500
commitd8a1a000555ecd1b824ac1ed6df8fe364dfbbbb0 (patch)
treefe0ba252cdf5aed298444abfbdc989991ec0e84b /fs/nfsd
parent15ca08d3299682dc49bad73251677b2c5017ef08 (diff)
downloadlinux-d8a1a000555ecd1b824ac1ed6df8fe364dfbbbb0.tar.bz2
nfsd: Fix another OPEN stateid race
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> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd')
-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 ee8fde2dfa92..457f0e7ece74 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4502,6 +4502,7 @@ 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,
@@ -4521,11 +4522,19 @@ 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) {
@@ -4533,22 +4542,11 @@ 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;
}
@@ -4557,7 +4555,7 @@ 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);