[PATCH] UBUNTU: [SAUCE] shiftfs: fix permanent -EOVERFLOW inside the CT
Alexander Mikhalitsyn
aleksandr.mikhalitsyn at canonical.com
Thu Nov 17 14:15:39 UTC 2022
BugLink: https://bugs.launchpad.net/bugs/1990849
We haven't supported idmapped layers with shiftfs and moreover, that makes
no sense. Once lower fs support idmapped mounts when shiftfs is not needed.
Starting from linux-image-5.15.0-48-generic users started seeing EOVERFLOW
errors from the userspace side on a trivial fs operations inside the containers.
This is caused by patches ("fs: tweak fsuidgid_has_mapping()"),
("fs: support mapped mounts of mapped filesystems"). These patches extends
and enables idmapped mounts support in Ubuntu kernel, but the problem is
that shiftfs was not properly ported.
See also:
("namei: prepare for idmapped mounts")
https://lore.kernel.org/all/20210121131959.646623-15-christian.brauner@ubuntu.com/
("overlayfs: do not mount on top of idmapped mounts")
https://lore.kernel.org/all/20210121131959.646623-29-christian.brauner@ubuntu.com/
as a reference.
Fixes: d347e71d2c0 ("UBUNTU: [SAUCE] shiftfs: support kernel 5.15")
Reported-by: Thomas Parrott <thomas.parrott at canonical.com>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn at canonical.com>
---
fs/shiftfs.c | 42 ++++++++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 16 deletions(-)
diff --git a/fs/shiftfs.c b/fs/shiftfs.c
index 76c54bc12018..9ea6e7ef06f9 100644
--- a/fs/shiftfs.c
+++ b/fs/shiftfs.c
@@ -379,8 +379,8 @@ static int shiftfs_xattr_set(const struct xattr_handler *handler,
int flags)
{
if (!value)
- return shiftfs_removexattr(ns, dentry, name);
- return shiftfs_setxattr(ns, dentry, inode, name, value, size, flags);
+ return shiftfs_removexattr(&init_user_ns, dentry, name);
+ return shiftfs_setxattr(&init_user_ns, dentry, inode, name, value, size, flags);
}
static int shiftfs_inode_test(struct inode *inode, void *data)
@@ -545,7 +545,7 @@ static int shiftfs_create(struct user_namespace *ns,
{
mode |= S_IFREG;
- return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, excl);
+ return shiftfs_create_object(&init_user_ns, dir, dentry, mode, NULL, NULL, excl);
}
static int shiftfs_mkdir(struct user_namespace *ns, struct inode *dir, struct dentry *dentry,
@@ -553,7 +553,7 @@ static int shiftfs_mkdir(struct user_namespace *ns, struct inode *dir, struct de
{
mode |= S_IFDIR;
- return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, false);
+ return shiftfs_create_object(&init_user_ns, dir, dentry, mode, NULL, NULL, false);
}
static int shiftfs_link(struct dentry *hardlink, struct inode *dir,
@@ -569,13 +569,13 @@ static int shiftfs_mknod(struct user_namespace *ns,
if (!S_ISFIFO(mode) && !S_ISSOCK(mode))
return -EPERM;
- return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, false);
+ return shiftfs_create_object(&init_user_ns, dir, dentry, mode, NULL, NULL, false);
}
static int shiftfs_symlink(struct user_namespace *ns, struct inode *dir, struct dentry *dentry,
const char *symlink)
{
- return shiftfs_create_object(ns, dir, dentry, S_IFLNK, symlink, NULL, false);
+ return shiftfs_create_object(&init_user_ns, dir, dentry, S_IFLNK, symlink, NULL, false);
}
static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
@@ -633,10 +633,10 @@ static int shiftfs_rename(struct user_namespace *ns,
struct inode *loweri_dir_old = lowerd_dir_old->d_inode,
*loweri_dir_new = lowerd_dir_new->d_inode;
struct renamedata rd = {
- .old_mnt_userns = ns,
+ .old_mnt_userns = &init_user_ns,
.old_dir = loweri_dir_old,
.old_dentry = lowerd_old,
- .new_mnt_userns = ns,
+ .new_mnt_userns = &init_user_ns,
.new_dir = loweri_dir_new,
.new_dentry = lowerd_new,
};
@@ -716,12 +716,12 @@ static int shiftfs_permission(struct user_namespace *ns, struct inode *inode, in
return -ECHILD;
}
- err = generic_permission(ns, inode, mask);
+ err = generic_permission(&init_user_ns, inode, mask);
if (err)
return err;
oldcred = shiftfs_override_creds(inode->i_sb);
- err = inode_permission(ns, loweri, mask);
+ err = inode_permission(&init_user_ns, loweri, mask);
revert_creds(oldcred);
return err;
@@ -760,7 +760,7 @@ static int shiftfs_tmpfile(struct user_namespace *ns,
return -EOPNOTSUPP;
oldcred = shiftfs_override_creds(dir->i_sb);
- err = loweri->i_op->tmpfile(ns, loweri, lowerd, mode);
+ err = loweri->i_op->tmpfile(&init_user_ns, loweri, lowerd, mode);
revert_creds(oldcred);
return err;
@@ -776,7 +776,7 @@ static int shiftfs_setattr(struct user_namespace *ns, struct dentry *dentry, str
struct shiftfs_super_info *sbinfo = sb->s_fs_info;
int err;
- err = setattr_prepare(ns, dentry, attr);
+ err = setattr_prepare(&init_user_ns, dentry, attr);
if (err)
return err;
@@ -793,7 +793,7 @@ static int shiftfs_setattr(struct user_namespace *ns, struct dentry *dentry, str
inode_lock(loweri);
oldcred = shiftfs_override_creds(dentry->d_sb);
- err = notify_change(ns, lowerd, &newattr, NULL);
+ err = notify_change(&init_user_ns, lowerd, &newattr, NULL);
revert_creds(oldcred);
inode_unlock(loweri);
@@ -973,17 +973,17 @@ shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler,
return -EOPNOTSUPP;
if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
return value ? -EACCES : 0;
- if (!inode_owner_or_capable(ns, inode))
+ if (!inode_owner_or_capable(&init_user_ns, inode))
return -EPERM;
if (value) {
shift_acl_xattr_ids(inode->i_sb->s_user_ns,
loweri->i_sb->s_user_ns,
(void *)value, size);
- err = shiftfs_setxattr(ns, dentry, inode, handler->name, value,
+ err = shiftfs_setxattr(&init_user_ns, dentry, inode, handler->name, value,
size, flags);
} else {
- err = shiftfs_removexattr(ns, dentry, handler->name);
+ err = shiftfs_removexattr(&init_user_ns, dentry, handler->name);
}
if (!err)
@@ -2017,6 +2017,16 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
goto out_put_path;
}
+ /*
+ * It makes no sense to handle idmapped layers from shiftfs.
+ * And we didn't support it properly anyway.
+ */
+ if (is_idmapped_mnt(path.mnt)) {
+ err = -EINVAL;
+ pr_err("idmapped layers are currently not supported\n");
+ goto out_put_path;
+ }
+
sb->s_flags |= SB_POSIXACL;
if (sbinfo->mark) {
--
2.34.1
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