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![Miklos Szeredi](/assets/img/avatar_default.png)
Don't let userspace filesystem give bogus values for the size of xattr and xattr list. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
211 lines
4.9 KiB
C
211 lines
4.9 KiB
C
/*
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* FUSE: Filesystem in Userspace
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* Copyright (C) 2001-2016 Miklos Szeredi <miklos@szeredi.hu>
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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/xattr.h>
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#include <linux/posix_acl_xattr.h>
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int fuse_setxattr(struct inode *inode, const char *name, const void *value,
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size_t size, int flags)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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FUSE_ARGS(args);
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struct fuse_setxattr_in inarg;
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int err;
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if (fc->no_setxattr)
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return -EOPNOTSUPP;
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memset(&inarg, 0, sizeof(inarg));
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inarg.size = size;
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inarg.flags = flags;
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args.in.h.opcode = FUSE_SETXATTR;
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args.in.h.nodeid = get_node_id(inode);
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args.in.numargs = 3;
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args.in.args[0].size = sizeof(inarg);
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args.in.args[0].value = &inarg;
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args.in.args[1].size = strlen(name) + 1;
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args.in.args[1].value = name;
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args.in.args[2].size = size;
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args.in.args[2].value = value;
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err = fuse_simple_request(fc, &args);
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if (err == -ENOSYS) {
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fc->no_setxattr = 1;
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err = -EOPNOTSUPP;
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}
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if (!err) {
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fuse_invalidate_attr(inode);
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fuse_update_ctime(inode);
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}
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return err;
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}
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ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
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size_t size)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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FUSE_ARGS(args);
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struct fuse_getxattr_in inarg;
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struct fuse_getxattr_out outarg;
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ssize_t ret;
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if (fc->no_getxattr)
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return -EOPNOTSUPP;
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memset(&inarg, 0, sizeof(inarg));
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inarg.size = size;
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args.in.h.opcode = FUSE_GETXATTR;
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args.in.h.nodeid = get_node_id(inode);
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args.in.numargs = 2;
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args.in.args[0].size = sizeof(inarg);
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args.in.args[0].value = &inarg;
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args.in.args[1].size = strlen(name) + 1;
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args.in.args[1].value = name;
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/* This is really two different operations rolled into one */
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args.out.numargs = 1;
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if (size) {
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args.out.argvar = 1;
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args.out.args[0].size = size;
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args.out.args[0].value = value;
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} else {
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args.out.args[0].size = sizeof(outarg);
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args.out.args[0].value = &outarg;
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}
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ret = fuse_simple_request(fc, &args);
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if (!ret && !size)
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ret = min_t(ssize_t, outarg.size, XATTR_SIZE_MAX);
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if (ret == -ENOSYS) {
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fc->no_getxattr = 1;
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ret = -EOPNOTSUPP;
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}
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return ret;
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}
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static int fuse_verify_xattr_list(char *list, size_t size)
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{
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size_t origsize = size;
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while (size) {
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size_t thislen = strnlen(list, size);
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if (!thislen || thislen == size)
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return -EIO;
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size -= thislen + 1;
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list += thislen + 1;
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}
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return origsize;
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}
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ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
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{
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struct inode *inode = d_inode(entry);
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struct fuse_conn *fc = get_fuse_conn(inode);
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FUSE_ARGS(args);
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struct fuse_getxattr_in inarg;
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struct fuse_getxattr_out outarg;
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ssize_t ret;
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if (!fuse_allow_current_process(fc))
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return -EACCES;
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if (fc->no_listxattr)
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return -EOPNOTSUPP;
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memset(&inarg, 0, sizeof(inarg));
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inarg.size = size;
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args.in.h.opcode = FUSE_LISTXATTR;
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args.in.h.nodeid = get_node_id(inode);
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args.in.numargs = 1;
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args.in.args[0].size = sizeof(inarg);
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args.in.args[0].value = &inarg;
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/* This is really two different operations rolled into one */
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args.out.numargs = 1;
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if (size) {
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args.out.argvar = 1;
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args.out.args[0].size = size;
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args.out.args[0].value = list;
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} else {
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args.out.args[0].size = sizeof(outarg);
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args.out.args[0].value = &outarg;
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}
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ret = fuse_simple_request(fc, &args);
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if (!ret && !size)
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ret = min_t(ssize_t, outarg.size, XATTR_LIST_MAX);
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if (ret > 0 && size)
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ret = fuse_verify_xattr_list(list, ret);
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if (ret == -ENOSYS) {
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fc->no_listxattr = 1;
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ret = -EOPNOTSUPP;
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}
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return ret;
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}
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int fuse_removexattr(struct inode *inode, const char *name)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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FUSE_ARGS(args);
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int err;
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if (fc->no_removexattr)
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return -EOPNOTSUPP;
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args.in.h.opcode = FUSE_REMOVEXATTR;
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args.in.h.nodeid = get_node_id(inode);
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args.in.numargs = 1;
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args.in.args[0].size = strlen(name) + 1;
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args.in.args[0].value = name;
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err = fuse_simple_request(fc, &args);
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if (err == -ENOSYS) {
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fc->no_removexattr = 1;
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err = -EOPNOTSUPP;
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}
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if (!err) {
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fuse_invalidate_attr(inode);
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fuse_update_ctime(inode);
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}
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return err;
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}
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static int fuse_xattr_get(const struct xattr_handler *handler,
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struct dentry *dentry, struct inode *inode,
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const char *name, void *value, size_t size)
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{
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return fuse_getxattr(inode, name, value, size);
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}
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static int fuse_xattr_set(const struct xattr_handler *handler,
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struct dentry *dentry, struct inode *inode,
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const char *name, const void *value, size_t size,
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int flags)
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{
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if (!value)
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return fuse_removexattr(inode, name);
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return fuse_setxattr(inode, name, value, size, flags);
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}
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static const struct xattr_handler fuse_xattr_handler = {
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.prefix = "",
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.get = fuse_xattr_get,
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.set = fuse_xattr_set,
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};
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const struct xattr_handler *fuse_xattr_handlers[] = {
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&fuse_xattr_handler,
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NULL
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};
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const struct xattr_handler *fuse_acl_xattr_handlers[] = {
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&posix_acl_access_xattr_handler,
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&posix_acl_default_xattr_handler,
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&fuse_xattr_handler,
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NULL
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};
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