The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 42d0c4bdf753063b6eec55415003184d3ca24f6e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '1678704830213151@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

42d0c4bdf753 ("filelocks: use mount idmapping for setlease permission check") c65454a94726 ("fs: remove locks_inode") 5970e15dbcfe ("filelock: move file locking definitions to separate header file") 8e1858710d9a ("ceph: avoid use-after-free in ceph_fl_release_lock()") 461ab10ef7e6 ("ceph: switch to vfs_inode_has_locks() to fix file lock bug") 6a518afcc206 ("Merge tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 42d0c4bdf753063b6eec55415003184d3ca24f6e Mon Sep 17 00:00:00 2001 From: Seth Forshee sforshee@kernel.org Date: Thu, 9 Mar 2023 14:39:09 -0600 Subject: [PATCH] filelocks: use mount idmapping for setlease permission check

A user should be allowed to take out a lease via an idmapped mount if the fsuid matches the mapped uid of the inode. generic_setlease() is checking the unmapped inode uid, causing these operations to be denied.

Fix this by comparing against the mapped inode uid instead of the unmapped uid.

Fixes: 9caccd41541a ("fs: introduce MOUNT_ATTR_IDMAP") Cc: stable@vger.kernel.org Signed-off-by: Seth Forshee (DigitalOcean) sforshee@kernel.org Signed-off-by: Christian Brauner (Microsoft) brauner@kernel.org

diff --git a/fs/locks.c b/fs/locks.c index d82c4cacdfb9..df8b26a42524 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1863,9 +1863,10 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp, void **priv) { struct inode *inode = file_inode(filp); + vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(filp), inode); int error;

- if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE)) + if ((!vfsuid_eq_kuid(vfsuid, current_fsuid())) && !capable(CAP_LEASE)) return -EACCES; if (!S_ISREG(inode->i_mode)) return -EINVAL;