[PATCH 08/24] ubifs: Enforce crypto policy in ->link and ->rename

From: Richard Weinberger
Date: Thu Dec 01 2016 - 16:26:29 EST


When a file is moved or linked into another directory
its current crypto policy has to be compatible with the
target policy.

Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
fs/ubifs/dir.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 477817567971..bd0af4e9ca0b 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -639,6 +639,10 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
ubifs_assert(inode_is_locked(dir));
ubifs_assert(inode_is_locked(inode));

+ if (ubifs_crypt_is_encrypted(dir) &&
+ !fscrypt_has_permitted_context(dir, inode))
+ return -EPERM;
+
err = dbg_check_synced_i_size(c, inode);
if (err)
return err;
@@ -1133,6 +1137,12 @@ static int do_rename(struct inode *old_dir, struct dentry *old_dentry,
if (unlink)
ubifs_assert(inode_is_locked(new_inode));

+ if (old_dir != new_dir) {
+ if (ubifs_crypt_is_encrypted(new_dir) &&
+ !fscrypt_has_permitted_context(new_dir, old_inode))
+ return -EPERM;
+ }
+
if (unlink && is_dir) {
err = ubifs_check_dir_empty(new_inode);
if (err)
@@ -1327,6 +1337,13 @@ static int ubifs_xrename(struct inode *old_dir, struct dentry *old_dentry,

ubifs_assert(fst_inode && snd_inode);

+ if ((ubifs_crypt_is_encrypted(old_dir) ||
+ ubifs_crypt_is_encrypted(new_dir)) &&
+ (old_dir != new_dir) &&
+ (!fscrypt_has_permitted_context(new_dir, fst_inode) ||
+ !fscrypt_has_permitted_context(old_dir, snd_inode)))
+ return -EPERM;
+
lock_4_inodes(old_dir, new_dir, NULL, NULL);

time = ubifs_current_time(old_dir);
--
2.7.3