From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.9 03/13] exportfs_decode_fh(): negative pinned may become positive without the parent locked
Date: Fri, 22 Nov 2019 14:49:48 -0500 [thread overview]
Message-ID: <20191122194958.24926-3-sashal@kernel.org> (raw)
In-Reply-To: <20191122194958.24926-1-sashal@kernel.org>
From: Al Viro <viro@zeniv.linux.org.uk>
[ Upstream commit a2ece088882666e1dc7113744ac912eb161e3f87 ]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/exportfs/expfs.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 7a7bba7c23284..3706939e5dd5e 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -506,26 +506,33 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
* inode is actually connected to the parent.
*/
err = exportfs_get_name(mnt, target_dir, nbuf, result);
- if (!err) {
- inode_lock(target_dir->d_inode);
- nresult = lookup_one_len(nbuf, target_dir,
- strlen(nbuf));
- inode_unlock(target_dir->d_inode);
- if (!IS_ERR(nresult)) {
- if (nresult->d_inode) {
- dput(result);
- result = nresult;
- } else
- dput(nresult);
- }
+ if (err) {
+ dput(target_dir);
+ goto err_result;
}
+ inode_lock(target_dir->d_inode);
+ nresult = lookup_one_len(nbuf, target_dir, strlen(nbuf));
+ if (!IS_ERR(nresult)) {
+ if (unlikely(nresult->d_inode != result->d_inode)) {
+ dput(nresult);
+ nresult = ERR_PTR(-ESTALE);
+ }
+ }
+ inode_unlock(target_dir->d_inode);
/*
* At this point we are done with the parent, but it's pinned
* by the child dentry anyway.
*/
dput(target_dir);
+ if (IS_ERR(nresult)) {
+ err = PTR_ERR(nresult);
+ goto err_result;
+ }
+ dput(result);
+ result = nresult;
+
/*
* And finally make sure the dentry is actually acceptable
* to NFSD.
--
2.20.1
next prev parent reply other threads:[~2019-11-22 19:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 19:49 [PATCH AUTOSEL 4.9 01/13] autofs: fix a leak in autofs_expire_indirect() Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 02/13] RDMA/hns: Correct the value of HNS_ROCE_HEM_CHUNK_LEN Sasha Levin
2019-11-22 19:49 ` Sasha Levin [this message]
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 04/13] audit_get_nd(): don't unlock parent too early Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 05/13] NFC: nxp-nci: Fix NULL pointer dereference after I2C communication error Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 06/13] Input: cyttsp4_core - fix use after free bug Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 07/13] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed() Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 08/13] slip: Fix memory leak in slip_open error path Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 09/13] net: cdc_ncm: Signedness bug in cdc_ncm_set_dgram_size() Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 10/13] slcan: Fix memory leak in error path Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 11/13] rsxx: add missed destroy_workqueue calls in remove Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 12/13] ax88172a: fix information leak on short answers Sasha Levin
2019-11-22 19:49 ` [PATCH AUTOSEL 4.9 13/13] net: ep93xx_eth: fix mismatch of request_mem_region in remove Sasha Levin
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