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2977db2632
Add CONFIG_FS_CHROOT and POSIX chroot(). Store the jail as an absolute path on the task group, and require euid 0 when user identity is enabled. Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
131 lines
3.4 KiB
C
131 lines
3.4 KiB
C
/****************************************************************************
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* fs/vfs/fs_chroot.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/stat.h>
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#include <assert.h>
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#include <errno.h>
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#include <string.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/sched.h>
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#include "inode/inode.h"
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#include "fs_heap.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: chroot
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*
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* Description:
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* Cause the named directory to become the root directory, that is, the
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* starting point for path names beginning with '/'.
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*
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* Input Parameters:
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* path - Directory to use as the new root
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*
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* Returned Value:
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* 0(OK) on success; -1(ERROR) on failure with errno set appropriately.
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*
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****************************************************************************/
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int chroot(FAR const char *path)
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{
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FAR struct tcb_s *rtcb;
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FAR struct task_group_s *group;
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FAR char *newroot;
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struct inode_search_s desc;
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struct stat buf;
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int ret;
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if (path == NULL || path[0] == '\0')
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{
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set_errno(ENOENT);
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return ERROR;
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}
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rtcb = nxsched_self();
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DEBUGASSERT(rtcb != NULL && rtcb->group != NULL);
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group = rtcb->group;
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#ifdef CONFIG_SCHED_USER_IDENTITY
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if (group->tg_euid != 0)
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{
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set_errno(EPERM);
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return ERROR;
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}
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#endif
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ret = stat(path, &buf);
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if (ret < 0)
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{
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return ERROR;
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}
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if (!S_ISDIR(buf.st_mode))
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{
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set_errno(ENOTDIR);
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return ERROR;
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}
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/* Resolve to a host absolute path the same way lookups do: make
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* absolute, prepend the current jail, and canonicalize. No second
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* inode walk.
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*/
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ret = inode_search_setup(&desc, path, true);
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if (ret < 0)
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{
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set_errno(-ret);
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return ERROR;
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}
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/* Host "/" means no jail. Clear any previous root. */
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if (strcmp(desc.path, "/") == 0)
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{
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fs_heap_free(group->tg_root);
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group->tg_root = NULL;
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inode_search_release(&desc);
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return OK;
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}
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newroot = fs_heap_strdup(desc.path);
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inode_search_release(&desc);
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if (newroot == NULL)
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{
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set_errno(ENOMEM);
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return ERROR;
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}
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fs_heap_free(group->tg_root);
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group->tg_root = newroot;
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return OK;
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}
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