From: Seth Forshee sforshee@kernel.org
[ Upstream commit 42d0c4bdf753063b6eec55415003184d3ca24f6e ]
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 --- fs/locks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/locks.c b/fs/locks.c index 82a4487e95b3..881fd16905c6 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1901,9 +1901,10 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp, void **priv) { struct inode *inode = locks_inode(filp); + kuid_t uid = i_uid_into_mnt(file_mnt_user_ns(filp), inode); int error;
- if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE)) + if ((!uid_eq(current_fsuid(), uid)) && !capable(CAP_LEASE)) return -EACCES; if (!S_ISREG(inode->i_mode)) return -EINVAL;