diff options
Diffstat (limited to 'fs/overlayfs/inode.c')
| -rw-r--r-- | fs/overlayfs/inode.c | 40 |
1 files changed, 38 insertions, 2 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 964a60fa7afc..49e204560655 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -42,6 +42,19 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) int err; struct dentry *upperdentry; + /* + * Check for permissions before trying to copy-up. This is redundant + * since it will be rechecked later by ->setattr() on upper dentry. But + * without this, copy-up can be triggered by just about anybody. + * + * We don't initialize inode->size, which just means that + * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not + * check for a swapfile (which this won't be anyway). + */ + err = inode_change_ok(dentry->d_inode, attr); + if (err) + return err; + err = ovl_want_write(dentry); if (err) goto out; @@ -50,9 +63,9 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) if (!err) { upperdentry = ovl_dentry_upper(dentry); - mutex_lock(&upperdentry->d_inode->i_mutex); + inode_lock(upperdentry->d_inode); err = notify_change(upperdentry, attr, NULL); - mutex_unlock(&upperdentry->d_inode->i_mutex); + inode_unlock(upperdentry->d_inode); } ovl_drop_write(dentry); out: @@ -95,6 +108,29 @@ int ovl_permission(struct inode *inode, int mask) realdentry = ovl_entry_real(oe, &is_upper); + if (ovl_is_default_permissions(inode)) { + struct kstat stat; + struct path realpath = { .dentry = realdentry }; + + if (mask & MAY_NOT_BLOCK) + return -ECHILD; + + realpath.mnt = ovl_entry_mnt_real(oe, inode, is_upper); + + err = vfs_getattr(&realpath, &stat); + if (err) + return err; + + if ((stat.mode ^ inode->i_mode) & S_IFMT) + return -ESTALE; + + inode->i_mode = stat.mode; + inode->i_uid = stat.uid; + inode->i_gid = stat.gid; + + return generic_permission(inode, mask); + } + /* Careful in RCU walk mode */ realinode = ACCESS_ONCE(realdentry->d_inode); if (!realinode) { |