From 47291baa8ddfdae10663624ff0a15ab165952708 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:24 +0100 Subject: namei: make permission helpers idmapped mount aware The two helpers inode_permission() and generic_permission() are used by the vfs to perform basic permission checking by verifying that the caller is privileged over an inode. In order to handle idmapped mounts we extend the two helpers with an additional user namespace argument. On idmapped mounts the two helpers will make sure to map the inode according to the mount's user namespace and then peform identical permission checks to inode_permission() and generic_permission(). If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Reviewed-by: James Morris Acked-by: Serge Hallyn Signed-off-by: Christian Brauner --- fs/overlayfs/file.c | 2 +- fs/overlayfs/inode.c | 4 ++-- fs/overlayfs/util.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'fs/overlayfs') diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index bd9dd38347ae..b2948e7b3210 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -50,7 +50,7 @@ static struct file *ovl_open_realfile(const struct file *file, acc_mode |= MAY_APPEND; old_cred = ovl_override_creds(inode->i_sb); - err = inode_permission(realinode, MAY_OPEN | acc_mode); + err = inode_permission(&init_user_ns, realinode, MAY_OPEN | acc_mode); if (err) { realfile = ERR_PTR(err); } else { diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index d739e14c6814..c101ebbb7a77 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -294,7 +294,7 @@ int ovl_permission(struct inode *inode, int mask) * Check overlay inode with the creds of task and underlying inode * with creds of mounter */ - err = generic_permission(inode, mask); + err = generic_permission(&init_user_ns, inode, mask); if (err) return err; @@ -305,7 +305,7 @@ int ovl_permission(struct inode *inode, int mask) /* Make sure mounter can read file for copy up later */ mask |= MAY_READ; } - err = inode_permission(realinode, mask); + err = inode_permission(&init_user_ns, realinode, mask); revert_creds(old_cred); return err; diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 6569031af3cd..de5c2047a0e9 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -479,7 +479,7 @@ struct file *ovl_path_open(struct path *path, int flags) BUG(); } - err = inode_permission(inode, acc_mode | MAY_OPEN); + err = inode_permission(&init_user_ns, inode, acc_mode | MAY_OPEN); if (err) return ERR_PTR(err); -- cgit v1.2.3