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fscrypto: lock inode while setting encryption policy

PATCH In review Eric Biggers 2 participants 2 messages Mar 16, 2017 – Mar 20, 2017

Subsystems (3)
Stable branch ext4 file system F2FS file system
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Eric Biggers

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PATCH 1/1 fscrypto: lock inode while setting encryption policy

From: Eric Biggers <[email protected]>

commit 8906a8223ad4909b391c5628f7991ebceda30e52 upstream. Please apply to 4.4-stable; it is already in 4.9-stable. This is a backport of the fix to fs/ext4/ and fs/f2fs/ for old kernels.

i_rwsem needs to be acquired while setting an encryption policy so that concurrent calls to FS_IOC_SET_ENCRYPTION_POLICY are correctly serialized (especially the ->get_context() + ->set_context() pair), and so that new files cannot be created in the directory during or after the ->empty_dir() check.

Signed-off-by Eric Biggers <[email protected]>
Signed-off-by Theodore Ts'o <[email protected]>
Reviewed-by Richard Weinberger <[email protected]>
Cc [email protected]
---
 fs/ext4/ioctl.c | 4 ++++
 fs/f2fs/file.c  | 9 ++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)
fs/ext4/ioctl.c +4 -0
index 1fb12f9c97a6..789e2d6724a9 100644
@@ -633,8 +633,12 @@ resizefs_out:
 		if (err)
 			goto encryption_policy_out;
 
+		mutex_lock(&inode->i_mutex);
+
 		err = ext4_process_policy(&policy, inode);
 
+		mutex_unlock(&inode->i_mutex);
+
 		mnt_drop_write_file(filp);
 encryption_policy_out:
 		return err;
fs/f2fs/file.c +8 -1
index a197215ad52b..4b449d263333 100644
@@ -1535,12 +1535,19 @@ static int f2fs_ioc_set_encryption_policy(struct file *filp, unsigned long arg)
 #ifdef CONFIG_F2FS_FS_ENCRYPTION
 	struct f2fs_encryption_policy policy;
 	struct inode *inode = file_inode(filp);
+	int err;
 
 	if (copy_from_user(&policy, (struct f2fs_encryption_policy __user *)arg,
 				sizeof(policy)))
 		return -EFAULT;
 
-	return f2fs_process_policy(&policy, inode);
+	mutex_lock(&inode->i_mutex);
+
+	err = f2fs_process_policy(&policy, inode);
+
+	mutex_unlock(&inode->i_mutex);
+
+	return err;
 #else
 	return -EOPNOTSUPP;
 #endif
Signature · 1 line
2.12.0.367.g23dc2f6d3c-goog
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#1 lore raw
Quoted 5 lines · Eric Biggers

From: Eric Biggers <[email protected]>

commit 8906a8223ad4909b391c5628f7991ebceda30e52 upstream. Please apply to 4.4-stable; it is already in 4.9-stable. This is a backport of the fix to fs/ext4/ and fs/f2fs/ for old kernels.

Thanks, now applied.

greg k-h