From e65ce2a50cf6af216bea6fd80d771fcbb4c0aaa1 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:27 +0100 Subject: acl: handle idmapped mounts The posix acl permission checking helpers determine whether a caller is privileged over an inode according to the acls associated with the inode. Add helpers that make it possible to handle acls on idmapped mounts. The vfs and the filesystems targeted by this first iteration make use of posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to translate basic posix access and default permissions such as the ACL_USER and ACL_GROUP type according to the initial user namespace (or the superblock's user namespace) to and from the caller's current user namespace. Adapt these two helpers to handle idmapped mounts whereby we either map from or into the mount's user namespace depending on in which direction we're translating. Similarly, cap_convert_nscap() is used by the vfs to translate user namespace and non-user namespace aware filesystem capabilities from the superblock's user namespace to the caller's user namespace. Enable it to handle idmapped mounts by accounting for the mount's user namespace. In addition the fileystems targeted in the first iteration of this patch series make use of the posix_acl_chmod() and, posix_acl_update_mode() helpers. Both helpers perform permission checks on the target inode. Let them handle idmapped mounts. These two helpers are called when posix acls are set by the respective filesystems to handle this case we extend the ->set() method to take an additional user namespace argument to pass the mount's user namespace down. Link: https://lore.kernel.org/r/20210121131959.646623-9-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/xfs/xfs_acl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_acl.c') diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c index 779cb73b3d00..368351298bd5 100644 --- a/fs/xfs/xfs_acl.c +++ b/fs/xfs/xfs_acl.c @@ -252,7 +252,8 @@ xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) return error; if (type == ACL_TYPE_ACCESS) { - error = posix_acl_update_mode(inode, &mode, &acl); + error = posix_acl_update_mode(&init_user_ns, inode, &mode, + &acl); if (error) return error; set_mode = true; -- cgit v1.2.3 From 549c7297717c32ee53f156cd949e055e601f67bb Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:43 +0100 Subject: fs: make helpers idmap mount aware Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/xfs/xfs_acl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_acl.c') diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c index 368351298bd5..332e87153c6c 100644 --- a/fs/xfs/xfs_acl.c +++ b/fs/xfs/xfs_acl.c @@ -238,7 +238,8 @@ xfs_acl_set_mode( } int -xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) +xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode, + struct posix_acl *acl, int type) { umode_t mode; bool set_mode = false; -- cgit v1.2.3 From f736d93d76d3e97d6986c6d26c8eaa32536ccc5c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 21 Jan 2021 14:19:58 +0100 Subject: xfs: support idmapped mounts Enable idmapped mounts for xfs. This basically just means passing down the user_namespace argument from the VFS methods down to where it is passed to the relevant helpers. Note that full-filesystem bulkstat is not supported from inside idmapped mounts as it is an administrative operation that acts on the whole file system. The limitation is not applied to the bulkstat single operation that just operates on a single inode. Link: https://lore.kernel.org/r/20210121131959.646623-40-christian.brauner@ubuntu.com Signed-off-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/xfs/xfs_acl.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'fs/xfs/xfs_acl.c') diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c index 332e87153c6c..d02bef24b32b 100644 --- a/fs/xfs/xfs_acl.c +++ b/fs/xfs/xfs_acl.c @@ -253,8 +253,7 @@ xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode, return error; if (type == ACL_TYPE_ACCESS) { - error = posix_acl_update_mode(&init_user_ns, inode, &mode, - &acl); + error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl); if (error) return error; set_mode = true; -- cgit v1.2.3