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![Eric W. Biederman](/assets/img/avatar_default.png)
- Pass the user namespace the uid and gid values in the xattr are stored in into posix_acl_from_xattr. - Pass the user namespace kuid and kgid values should be converted into when storing uid and gid values in an xattr in posix_acl_to_xattr. - Modify all callers of posix_acl_from_xattr and posix_acl_to_xattr to pass in &init_user_ns. In the short term this change is not strictly needed but it makes the code clearer. In the longer term this change is necessary to be able to mount filesystems outside of the initial user namespace that natively store posix acls in the linux xattr format. Cc: Theodore Tso <tytso@mit.edu> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
184 lines
3.9 KiB
C
184 lines
3.9 KiB
C
/*
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* (C) 2005 Andreas Gruenbacher <agruen@suse.de>
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*
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* This file is released under the GPL.
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*
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* Generic ACL support for in-memory filesystems.
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*/
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#include <linux/sched.h>
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#include <linux/gfp.h>
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#include <linux/fs.h>
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#include <linux/generic_acl.h>
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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static size_t
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generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
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const char *name, size_t name_len, int type)
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{
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struct posix_acl *acl;
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const char *xname;
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size_t size;
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acl = get_cached_acl(dentry->d_inode, type);
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if (!acl)
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return 0;
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posix_acl_release(acl);
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switch (type) {
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case ACL_TYPE_ACCESS:
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xname = POSIX_ACL_XATTR_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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xname = POSIX_ACL_XATTR_DEFAULT;
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break;
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default:
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return 0;
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}
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size = strlen(xname) + 1;
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if (list && size <= list_size)
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memcpy(list, xname, size);
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return size;
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}
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static int
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generic_acl_get(struct dentry *dentry, const char *name, void *buffer,
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size_t size, int type)
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{
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struct posix_acl *acl;
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int error;
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if (strcmp(name, "") != 0)
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return -EINVAL;
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acl = get_cached_acl(dentry->d_inode, type);
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if (!acl)
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return -ENODATA;
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error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
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posix_acl_release(acl);
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return error;
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}
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static int
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generic_acl_set(struct dentry *dentry, const char *name, const void *value,
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size_t size, int flags, int type)
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{
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struct inode *inode = dentry->d_inode;
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struct posix_acl *acl = NULL;
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int error;
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if (strcmp(name, "") != 0)
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return -EINVAL;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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if (!inode_owner_or_capable(inode))
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return -EPERM;
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if (value) {
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acl = posix_acl_from_xattr(&init_user_ns, value, size);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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}
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if (acl) {
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error = posix_acl_valid(acl);
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if (error)
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goto failed;
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switch (type) {
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case ACL_TYPE_ACCESS:
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error = posix_acl_equiv_mode(acl, &inode->i_mode);
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if (error < 0)
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goto failed;
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inode->i_ctime = CURRENT_TIME;
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if (error == 0) {
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posix_acl_release(acl);
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acl = NULL;
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}
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break;
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case ACL_TYPE_DEFAULT:
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if (!S_ISDIR(inode->i_mode)) {
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error = -EINVAL;
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goto failed;
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}
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break;
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}
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}
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set_cached_acl(inode, type, acl);
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error = 0;
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failed:
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posix_acl_release(acl);
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return error;
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}
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/**
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* generic_acl_init - Take care of acl inheritance at @inode create time
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*
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* Files created inside a directory with a default ACL inherit the
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* directory's default ACL.
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*/
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int
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generic_acl_init(struct inode *inode, struct inode *dir)
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{
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struct posix_acl *acl = NULL;
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int error;
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if (!S_ISLNK(inode->i_mode))
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acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
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if (acl) {
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if (S_ISDIR(inode->i_mode))
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set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
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error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
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if (error < 0)
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return error;
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if (error > 0)
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set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
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} else {
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inode->i_mode &= ~current_umask();
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}
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error = 0;
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posix_acl_release(acl);
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return error;
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}
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/**
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* generic_acl_chmod - change the access acl of @inode upon chmod()
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*
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* A chmod also changes the permissions of the owner, group/mask, and
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* other ACL entries.
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*/
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int
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generic_acl_chmod(struct inode *inode)
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{
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struct posix_acl *acl;
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int error = 0;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
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if (acl) {
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error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
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if (error)
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return error;
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set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
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posix_acl_release(acl);
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}
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return error;
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}
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const struct xattr_handler generic_acl_access_handler = {
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.prefix = POSIX_ACL_XATTR_ACCESS,
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.flags = ACL_TYPE_ACCESS,
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.list = generic_acl_list,
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.get = generic_acl_get,
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.set = generic_acl_set,
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};
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const struct xattr_handler generic_acl_default_handler = {
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.prefix = POSIX_ACL_XATTR_DEFAULT,
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.flags = ACL_TYPE_DEFAULT,
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.list = generic_acl_list,
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.get = generic_acl_get,
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.set = generic_acl_set,
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};
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