[PATCH v3 03/33] ecryptfs: don't leak the inode when a lookup can't open the lower file

[Christian Brauner <brauner@kernel.org>]

ecryptfs_lookup_interpose() opens the lower file of a regular file to
read the size from the header. If that fails it marks the inode bad and
returns, but a new inode is still I_NEW and nobody ever unlocks or puts
it. So it leaks together with its lower inode, a concurrent lookup
through another hard link waits for it forever and umount complains
about busy inodes. The lower open fails e.g. with ETXTBSY while the
lower file is executed. A cached inode is marked bad for all its other
users instead.

Use iget_failed() for a new inode and iput() for a cached one.

Fixes: 3b06b3ebf441 ("eCryptfs: Fix new inode race condition")
Cc: stable@vger.kernel.org
Reported-by: Farhad Alemi <farhad.alemi@berkeley.edu>
Closes: https://lore.kernel.org/r/CA+0ovCgYP920GT68hAJK6Trjyv1kGv2dZAuem4LEunycQ=POww@mail.gmail.com
Acked-by: Tyler Hicks <code@tyhicks.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/ecryptfs/inode.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 48e520960d665..3a966348a578a 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -362,7 +362,10 @@ static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 	if (S_ISREG(inode->i_mode)) {
 		rc = ecryptfs_i_size_read(dentry, inode);
 		if (rc) {
-			make_bad_inode(inode);
+			if (inode_state_read_once(inode) & I_NEW)
+				iget_failed(inode);
+			else
+				iput(inode);
 			return ERR_PTR(rc);
 		}
 	}

-- 
2.53.0


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