linux-kernel - [PATCH 09/10] f2fs crypto: sync ext4_lookup and ext4_file

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Date:	Wed,  2 Mar 2016 10:31:17 -0800
From:	Jaegeuk Kim <jaegeuk@...nel.org>
To:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net, tytso@....edu
Cc:	Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 09/10] f2fs crypto: sync ext4_lookup and ext4_file_open

This patch tries to catch up with lookup and open policies in ext4.

Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
 fs/f2fs/dir.c   |  2 +-
 fs/f2fs/file.c  |  4 ++++
 fs/f2fs/namei.c | 23 +++++++++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index f82e28b..479467e 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -855,7 +855,7 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
 
 	if (f2fs_encrypted_inode(inode)) {
 		err = fscrypt_get_encryption_info(inode);
-		if (err)
+		if (err && err != -ENOKEY)
 			return err;
 
 		err = fscrypt_fname_alloc_buffer(inode, F2FS_NAME_LEN, &fstr);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f326764..533c2dc 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -441,6 +441,7 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
 static int f2fs_file_open(struct inode *inode, struct file *filp)
 {
 	int ret = generic_file_open(inode, filp);
+	struct inode *dir = filp->f_path.dentry->d_parent->d_inode;
 
 	if (!ret && f2fs_encrypted_inode(inode)) {
 		ret = fscrypt_get_encryption_info(inode);
@@ -449,6 +450,9 @@ static int f2fs_file_open(struct inode *inode, struct file *filp)
 		if (!f2fs_encrypted_inode(inode))
 			return -ENOKEY;
 	}
+	if (f2fs_encrypted_inode(dir) &&
+			!fscrypt_has_permitted_context(dir, inode))
+		return -EPERM;
 	return ret;
 }
 
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 3bddd9f..7b07a47 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -262,6 +262,21 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 	int err = 0;
 	unsigned int root_ino = F2FS_ROOT_INO(F2FS_I_SB(dir));
 
+	if (f2fs_encrypted_inode(dir)) {
+		int res = fscrypt_get_encryption_info(dir);
+
+		/*
+		 * DCACHE_ENCRYPTED_WITH_KEY is set if the dentry is
+		 * created while the directory was encrypted and we
+		 * don't have access to the key.
+		 */
+		if (fscrypt_has_encryption_key(dir))
+			fscrypt_set_encrypted_dentry(dentry);
+		fscrypt_set_d_op(dentry);
+		if (res && res != -ENOKEY)
+			return ERR_PTR(res);
+	}
+
 	if (dentry->d_name.len > F2FS_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
@@ -288,6 +303,14 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		if (err)
 			goto err_out;
 	}
+	if (!IS_ERR(inode) && f2fs_encrypted_inode(dir) &&
+			(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
+			!fscrypt_has_permitted_context(dir, inode)) {
+		bool nokey = f2fs_encrypted_inode(inode) &&
+			!fscrypt_has_encryption_key(inode);
+		iput(inode);
+		return nokey ? ERR_PTR(-ENOKEY) : ERR_PTR(-EPERM);
+	}
 	return d_splice_alias(inode, dentry);
 
 err_out:
-- 
2.6.3