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FAILED: patch "[PATCH] ext4/fscrypto: avoid RCU lookup in d_revalidate" failed to apply to 4.5-stable tree

PATCH [email protected] 1 participant 1 message Apr 27, 2016

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Stable branch ext4 file system fscrypt: file system level encryption support
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The patch below does not apply to the 4.5-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 03a8bb0e53d9562276045bdfcf2b5de2e4cff5a1 Mon Sep 17 00:00:00 2001

From: Jaegeuk Kim <[email protected]>
Date: Tue, 12 Apr 2016 16:05:36 -0700
Subject: [PATCH] ext4/fscrypto: avoid RCU lookup in d_revalidate

As Al pointed, d_revalidate should return RCU lookup before using d_inode. This was originally introduced by:
commit 34286d666230 ("fs: rcu-walk aware d_revalidate method").

Reported-by Al Viro <[email protected]>
Signed-off-by Jaegeuk Kim <[email protected]>
Cc Theodore Ts'o <[email protected]>
Cc stable <[email protected]>
fs/crypto/crypto.c +4 -0
index da70520f3ab4..2fc8c43ce531 100644
@@ -26,6 +26,7 @@
 #include <linux/ratelimit.h>
 #include <linux/bio.h>
 #include <linux/dcache.h>
+#include <linux/namei.h>
 #include <linux/fscrypto.h>
 #include <linux/ecryptfs.h>
 

@@ -353,6 +354,9 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 	struct fscrypt_info *ci;
 	int dir_has_key, cached_with_key;
 
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
 	dir = dget_parent(dentry);
 	if (!d_inode(dir)->i_sb->s_cop->is_encrypted(d_inode(dir))) {
 		dput(dir);
fs/ext4/crypto.c +4 -0
index db9ae6e18154..6a6c27373b54 100644
@@ -32,6 +32,7 @@
 #include <linux/random.h>
 #include <linux/scatterlist.h>
 #include <linux/spinlock_types.h>
+#include <linux/namei.h>
 
 #include "ext4_extents.h"
 #include "xattr.h"

@@ -482,6 +483,9 @@ static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
 	struct ext4_crypt_info *ci;
 	int dir_has_key, cached_with_key;
 
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
 	dir = dget_parent(dentry);
 	if (!ext4_encrypted_inode(d_inode(dir))) {
 		dput(dir);