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549c729771
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 <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/*
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* FUSE: Filesystem in Userspace
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* Copyright (C) 2016 Canonical Ltd. <seth.forshee@canonical.com>
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*
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* This program can be distributed under the terms of the GNU GPL.
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* See the file COPYING.
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*/
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#include "fuse_i.h"
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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struct posix_acl *fuse_get_acl(struct inode *inode, int type)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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int size;
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const char *name;
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void *value = NULL;
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struct posix_acl *acl;
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if (fuse_is_bad(inode))
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return ERR_PTR(-EIO);
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if (!fc->posix_acl || fc->no_getxattr)
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return NULL;
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if (type == ACL_TYPE_ACCESS)
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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else if (type == ACL_TYPE_DEFAULT)
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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else
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return ERR_PTR(-EOPNOTSUPP);
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value = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (!value)
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return ERR_PTR(-ENOMEM);
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size = fuse_getxattr(inode, name, value, PAGE_SIZE);
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if (size > 0)
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acl = posix_acl_from_xattr(fc->user_ns, value, size);
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else if ((size == 0) || (size == -ENODATA) ||
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(size == -EOPNOTSUPP && fc->no_getxattr))
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acl = NULL;
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else if (size == -ERANGE)
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acl = ERR_PTR(-E2BIG);
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else
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acl = ERR_PTR(size);
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kfree(value);
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return acl;
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}
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int fuse_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
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struct posix_acl *acl, int type)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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const char *name;
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int ret;
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if (fuse_is_bad(inode))
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return -EIO;
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if (!fc->posix_acl || fc->no_setxattr)
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return -EOPNOTSUPP;
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if (type == ACL_TYPE_ACCESS)
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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else if (type == ACL_TYPE_DEFAULT)
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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else
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return -EINVAL;
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if (acl) {
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/*
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* Fuse userspace is responsible for updating access
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* permissions in the inode, if needed. fuse_setxattr
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* invalidates the inode attributes, which will force
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* them to be refreshed the next time they are used,
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* and it also updates i_ctime.
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*/
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size_t size = posix_acl_xattr_size(acl->a_count);
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void *value;
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if (size > PAGE_SIZE)
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return -E2BIG;
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value = kmalloc(size, GFP_KERNEL);
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if (!value)
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return -ENOMEM;
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ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
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if (ret < 0) {
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kfree(value);
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return ret;
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}
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ret = fuse_setxattr(inode, name, value, size, 0);
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kfree(value);
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} else {
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ret = fuse_removexattr(inode, name);
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}
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forget_all_cached_acls(inode);
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fuse_invalidate_attr(inode);
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return ret;
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}
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