From: Theodore Ts'o Date: Sat, 26 Mar 2016 20:15:42 +0000 (-0400) Subject: ext4 crypto: use dget_parent() in ext4_d_revalidate() X-Git-Tag: release-20171130_firefly~4^2~100^2~1^2~9^2~64 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=41948f88a521b95e8abc793602015a6d45f52a06;p=firefly-linux-kernel-4.4.55.git ext4 crypto: use dget_parent() in ext4_d_revalidate() commit 3d43bcfef5f0548845a425365011c499875491b0 upstream. This avoids potential problems caused by a race where the inode gets renamed out from its parent directory and the parent directory is deleted while ext4_d_revalidate() is running. Fixes: 28b4c263961c Reported-by: Al Viro Signed-off-by: Theodore Ts'o Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 13a69e0fb90d..1259ade2f10a 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -477,16 +477,21 @@ uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size) */ static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags) { - struct inode *dir = d_inode(dentry->d_parent); - struct ext4_crypt_info *ci = EXT4_I(dir)->i_crypt_info; + struct dentry *dir; + struct ext4_crypt_info *ci; int dir_has_key, cached_with_key; - if (!ext4_encrypted_inode(dir)) + dir = dget_parent(dentry); + if (!ext4_encrypted_inode(d_inode(dir))) { + dput(dir); return 0; + } + ci = EXT4_I(d_inode(dir))->i_crypt_info; /* this should eventually be an flag in d_flags */ cached_with_key = dentry->d_fsdata != NULL; dir_has_key = (ci != NULL); + dput(dir); /* * If the dentry was cached without the key, and it is a