From c20fb060ce083bbc9b6dd07483a482a9d378c2fb Mon Sep 17 00:00:00 2001 From: Seth Forshee Date: Thu, 9 Mar 2023 14:39:09 -0600 Subject: [PATCH] filelocks: use mount idmapping for setlease permission check commit 42d0c4bdf753063b6eec55415003184d3ca24f6e upstream. 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) Signed-off-by: Christian Brauner (Microsoft) Signed-off-by: Greg Kroah-Hartman --- fs/locks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/locks.c b/fs/locks.c index 8f01bee17715..8a881cda3dd2 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1862,9 +1862,10 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp, void **priv) { struct inode *inode = locks_inode(filp); + vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_user_ns(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;