All vm_object_page_remove() callers, except linux_invalidate_mapping_pages() in the LinuxKPI, free swap space when removing a range of pages from an object. The LinuxKPI case appears to be an unintentional omission that could result in leaked swap blocks, so unconditionally free swap space in vm_object_page_remove() to protect against similar bugs in the future. Reviewed by: alc, kib Tested by: pho Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D25329
1558 lines
39 KiB
C
1558 lines
39 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2006, 2011, 2016-2017 Robert N. M. Watson
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* All rights reserved.
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*
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* Portions of this software were developed by BAE Systems, the University of
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* Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
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* contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
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* Computing (TC) research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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* SUCH DAMAGE.
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*/
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|
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/*
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* Support for shared swap-backed anonymous memory objects via
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* shm_open(2), shm_rename(2), and shm_unlink(2).
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* While most of the implementation is here, vm_mmap.c contains
|
|
* mapping logic changes.
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*
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* posixshmcontrol(1) allows users to inspect the state of the memory
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|
* objects. Per-uid swap resource limit controls total amount of
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* memory that user can consume for anonymous objects, including
|
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* shared.
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*/
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|
|
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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|
|
|
#include "opt_capsicum.h"
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|
#include "opt_ktrace.h"
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|
|
|
#include <sys/param.h>
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|
#include <sys/capsicum.h>
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|
#include <sys/conf.h>
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|
#include <sys/fcntl.h>
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|
#include <sys/file.h>
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|
#include <sys/filedesc.h>
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|
#include <sys/filio.h>
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|
#include <sys/fnv_hash.h>
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|
#include <sys/kernel.h>
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|
#include <sys/limits.h>
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|
#include <sys/uio.h>
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|
#include <sys/signal.h>
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|
#include <sys/jail.h>
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|
#include <sys/ktrace.h>
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|
#include <sys/lock.h>
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|
#include <sys/malloc.h>
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|
#include <sys/mman.h>
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|
#include <sys/mutex.h>
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|
#include <sys/priv.h>
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|
#include <sys/proc.h>
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|
#include <sys/refcount.h>
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|
#include <sys/resourcevar.h>
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|
#include <sys/rwlock.h>
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|
#include <sys/sbuf.h>
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|
#include <sys/stat.h>
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|
#include <sys/syscallsubr.h>
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|
#include <sys/sysctl.h>
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|
#include <sys/sysproto.h>
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|
#include <sys/systm.h>
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|
#include <sys/sx.h>
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|
#include <sys/time.h>
|
|
#include <sys/vnode.h>
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|
#include <sys/unistd.h>
|
|
#include <sys/user.h>
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|
|
|
#include <security/audit/audit.h>
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|
#include <security/mac/mac_framework.h>
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|
|
|
#include <vm/vm.h>
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|
#include <vm/vm_param.h>
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|
#include <vm/pmap.h>
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|
#include <vm/vm_extern.h>
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|
#include <vm/vm_map.h>
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|
#include <vm/vm_kern.h>
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|
#include <vm/vm_object.h>
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|
#include <vm/vm_page.h>
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|
#include <vm/vm_pageout.h>
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|
#include <vm/vm_pager.h>
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|
#include <vm/swap_pager.h>
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|
|
|
struct shm_mapping {
|
|
char *sm_path;
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|
Fnv32_t sm_fnv;
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|
struct shmfd *sm_shmfd;
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|
LIST_ENTRY(shm_mapping) sm_link;
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|
};
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|
|
|
static MALLOC_DEFINE(M_SHMFD, "shmfd", "shared memory file descriptor");
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|
static LIST_HEAD(, shm_mapping) *shm_dictionary;
|
|
static struct sx shm_dict_lock;
|
|
static struct mtx shm_timestamp_lock;
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|
static u_long shm_hash;
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|
static struct unrhdr64 shm_ino_unr;
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|
static dev_t shm_dev_ino;
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|
|
|
#define SHM_HASH(fnv) (&shm_dictionary[(fnv) & shm_hash])
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|
|
|
static void shm_init(void *arg);
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|
static void shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd);
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|
static struct shmfd *shm_lookup(char *path, Fnv32_t fnv);
|
|
static int shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred);
|
|
static int shm_dotruncate_locked(struct shmfd *shmfd, off_t length,
|
|
void *rl_cookie);
|
|
static int shm_copyin_path(struct thread *td, const char *userpath_in,
|
|
char **path_out);
|
|
|
|
static fo_rdwr_t shm_read;
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|
static fo_rdwr_t shm_write;
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|
static fo_truncate_t shm_truncate;
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|
static fo_ioctl_t shm_ioctl;
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|
static fo_stat_t shm_stat;
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|
static fo_close_t shm_close;
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|
static fo_chmod_t shm_chmod;
|
|
static fo_chown_t shm_chown;
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|
static fo_seek_t shm_seek;
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|
static fo_fill_kinfo_t shm_fill_kinfo;
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|
static fo_mmap_t shm_mmap;
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|
static fo_get_seals_t shm_get_seals;
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|
static fo_add_seals_t shm_add_seals;
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|
static fo_fallocate_t shm_fallocate;
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|
|
|
/* File descriptor operations. */
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|
struct fileops shm_ops = {
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.fo_read = shm_read,
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.fo_write = shm_write,
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.fo_truncate = shm_truncate,
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|
.fo_ioctl = shm_ioctl,
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|
.fo_poll = invfo_poll,
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|
.fo_kqfilter = invfo_kqfilter,
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|
.fo_stat = shm_stat,
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|
.fo_close = shm_close,
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|
.fo_chmod = shm_chmod,
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|
.fo_chown = shm_chown,
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|
.fo_sendfile = vn_sendfile,
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|
.fo_seek = shm_seek,
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|
.fo_fill_kinfo = shm_fill_kinfo,
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|
.fo_mmap = shm_mmap,
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|
.fo_get_seals = shm_get_seals,
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|
.fo_add_seals = shm_add_seals,
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|
.fo_fallocate = shm_fallocate,
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|
.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
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|
};
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|
|
|
FEATURE(posix_shm, "POSIX shared memory");
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|
|
static int
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|
uiomove_object_page(vm_object_t obj, size_t len, struct uio *uio)
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|
{
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|
vm_page_t m;
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|
vm_pindex_t idx;
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|
size_t tlen;
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int error, offset, rv;
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idx = OFF_TO_IDX(uio->uio_offset);
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offset = uio->uio_offset & PAGE_MASK;
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tlen = MIN(PAGE_SIZE - offset, len);
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|
rv = vm_page_grab_valid_unlocked(&m, obj, idx,
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VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | VM_ALLOC_NOCREAT);
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|
if (rv == VM_PAGER_OK)
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goto found;
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|
|
/*
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|
* Read I/O without either a corresponding resident page or swap
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|
* page: use zero_region. This is intended to avoid instantiating
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* pages on read from a sparse region.
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*/
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VM_OBJECT_WLOCK(obj);
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m = vm_page_lookup(obj, idx);
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|
if (uio->uio_rw == UIO_READ && m == NULL &&
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!vm_pager_has_page(obj, idx, NULL, NULL)) {
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|
VM_OBJECT_WUNLOCK(obj);
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|
return (uiomove(__DECONST(void *, zero_region), tlen, uio));
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|
}
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|
|
|
/*
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|
* Although the tmpfs vnode lock is held here, it is
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|
* nonetheless safe to sleep waiting for a free page. The
|
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* pageout daemon does not need to acquire the tmpfs vnode
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* lock to page out tobj's pages because tobj is a OBJT_SWAP
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* type object.
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*/
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rv = vm_page_grab_valid(&m, obj, idx,
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VM_ALLOC_NORMAL | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY);
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if (rv != VM_PAGER_OK) {
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|
VM_OBJECT_WUNLOCK(obj);
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|
printf("uiomove_object: vm_obj %p idx %jd pager error %d\n",
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|
obj, idx, rv);
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|
return (EIO);
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|
}
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|
VM_OBJECT_WUNLOCK(obj);
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|
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found:
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|
error = uiomove_fromphys(&m, offset, tlen, uio);
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if (uio->uio_rw == UIO_WRITE && error == 0)
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vm_page_set_dirty(m);
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vm_page_activate(m);
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vm_page_sunbusy(m);
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|
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|
return (error);
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|
}
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|
|
int
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uiomove_object(vm_object_t obj, off_t obj_size, struct uio *uio)
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|
{
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|
ssize_t resid;
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|
size_t len;
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|
int error;
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|
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|
error = 0;
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while ((resid = uio->uio_resid) > 0) {
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if (obj_size <= uio->uio_offset)
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break;
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len = MIN(obj_size - uio->uio_offset, resid);
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if (len == 0)
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break;
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error = uiomove_object_page(obj, len, uio);
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if (error != 0 || resid == uio->uio_resid)
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break;
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}
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return (error);
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|
}
|
|
|
|
static int
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|
shm_seek(struct file *fp, off_t offset, int whence, struct thread *td)
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|
{
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|
struct shmfd *shmfd;
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|
off_t foffset;
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|
int error;
|
|
|
|
shmfd = fp->f_data;
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foffset = foffset_lock(fp, 0);
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error = 0;
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switch (whence) {
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case L_INCR:
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|
if (foffset < 0 ||
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(offset > 0 && foffset > OFF_MAX - offset)) {
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error = EOVERFLOW;
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break;
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|
}
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offset += foffset;
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|
break;
|
|
case L_XTND:
|
|
if (offset > 0 && shmfd->shm_size > OFF_MAX - offset) {
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error = EOVERFLOW;
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break;
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|
}
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|
offset += shmfd->shm_size;
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break;
|
|
case L_SET:
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break;
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|
default:
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error = EINVAL;
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|
}
|
|
if (error == 0) {
|
|
if (offset < 0 || offset > shmfd->shm_size)
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|
error = EINVAL;
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|
else
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td->td_uretoff.tdu_off = offset;
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|
}
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|
foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
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|
return (error);
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|
}
|
|
|
|
static int
|
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shm_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
|
|
int flags, struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
void *rl_cookie;
|
|
int error;
|
|
|
|
shmfd = fp->f_data;
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_read(active_cred, fp->f_cred, shmfd);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
foffset_lock_uio(fp, uio, flags);
|
|
rl_cookie = rangelock_rlock(&shmfd->shm_rl, uio->uio_offset,
|
|
uio->uio_offset + uio->uio_resid, &shmfd->shm_mtx);
|
|
error = uiomove_object(shmfd->shm_object, shmfd->shm_size, uio);
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
|
|
foffset_unlock_uio(fp, uio, flags);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
shm_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
|
|
int flags, struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
void *rl_cookie;
|
|
int error;
|
|
|
|
shmfd = fp->f_data;
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_write(active_cred, fp->f_cred, shmfd);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
foffset_lock_uio(fp, uio, flags);
|
|
if ((flags & FOF_OFFSET) == 0) {
|
|
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
|
|
&shmfd->shm_mtx);
|
|
} else {
|
|
rl_cookie = rangelock_wlock(&shmfd->shm_rl, uio->uio_offset,
|
|
uio->uio_offset + uio->uio_resid, &shmfd->shm_mtx);
|
|
}
|
|
if ((shmfd->shm_seals & F_SEAL_WRITE) != 0)
|
|
error = EPERM;
|
|
else
|
|
error = uiomove_object(shmfd->shm_object, shmfd->shm_size, uio);
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
|
|
foffset_unlock_uio(fp, uio, flags);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
shm_truncate(struct file *fp, off_t length, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
#ifdef MAC
|
|
int error;
|
|
#endif
|
|
|
|
shmfd = fp->f_data;
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_truncate(active_cred, fp->f_cred, shmfd);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
return (shm_dotruncate(shmfd, length));
|
|
}
|
|
|
|
int
|
|
shm_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
|
|
switch (com) {
|
|
case FIONBIO:
|
|
case FIOASYNC:
|
|
/*
|
|
* Allow fcntl(fd, F_SETFL, O_NONBLOCK) to work,
|
|
* just like it would on an unlinked regular file
|
|
*/
|
|
return (0);
|
|
default:
|
|
return (ENOTTY);
|
|
}
|
|
}
|
|
|
|
static int
|
|
shm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
#ifdef MAC
|
|
int error;
|
|
#endif
|
|
|
|
shmfd = fp->f_data;
|
|
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_stat(active_cred, fp->f_cred, shmfd);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
|
|
/*
|
|
* Attempt to return sanish values for fstat() on a memory file
|
|
* descriptor.
|
|
*/
|
|
bzero(sb, sizeof(*sb));
|
|
sb->st_blksize = PAGE_SIZE;
|
|
sb->st_size = shmfd->shm_size;
|
|
sb->st_blocks = howmany(sb->st_size, sb->st_blksize);
|
|
mtx_lock(&shm_timestamp_lock);
|
|
sb->st_atim = shmfd->shm_atime;
|
|
sb->st_ctim = shmfd->shm_ctime;
|
|
sb->st_mtim = shmfd->shm_mtime;
|
|
sb->st_birthtim = shmfd->shm_birthtime;
|
|
sb->st_mode = S_IFREG | shmfd->shm_mode; /* XXX */
|
|
sb->st_uid = shmfd->shm_uid;
|
|
sb->st_gid = shmfd->shm_gid;
|
|
mtx_unlock(&shm_timestamp_lock);
|
|
sb->st_dev = shm_dev_ino;
|
|
sb->st_ino = shmfd->shm_ino;
|
|
sb->st_nlink = shmfd->shm_object->ref_count;
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
shm_close(struct file *fp, struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
|
|
shmfd = fp->f_data;
|
|
fp->f_data = NULL;
|
|
shm_drop(shmfd);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
shm_copyin_path(struct thread *td, const char *userpath_in, char **path_out) {
|
|
int error;
|
|
char *path;
|
|
const char *pr_path;
|
|
size_t pr_pathlen;
|
|
|
|
path = malloc(MAXPATHLEN, M_SHMFD, M_WAITOK);
|
|
pr_path = td->td_ucred->cr_prison->pr_path;
|
|
|
|
/* Construct a full pathname for jailed callers. */
|
|
pr_pathlen = strcmp(pr_path, "/") ==
|
|
0 ? 0 : strlcpy(path, pr_path, MAXPATHLEN);
|
|
error = copyinstr(userpath_in, path + pr_pathlen,
|
|
MAXPATHLEN - pr_pathlen, NULL);
|
|
if (error != 0)
|
|
goto out;
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(curthread, KTR_NAMEI))
|
|
ktrnamei(path);
|
|
#endif
|
|
|
|
/* Require paths to start with a '/' character. */
|
|
if (path[pr_pathlen] != '/') {
|
|
error = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
*path_out = path;
|
|
|
|
out:
|
|
if (error != 0)
|
|
free(path, M_SHMFD);
|
|
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
shm_dotruncate_locked(struct shmfd *shmfd, off_t length, void *rl_cookie)
|
|
{
|
|
vm_object_t object;
|
|
vm_page_t m;
|
|
vm_pindex_t idx, nobjsize;
|
|
vm_ooffset_t delta;
|
|
int base, rv;
|
|
|
|
KASSERT(length >= 0, ("shm_dotruncate: length < 0"));
|
|
object = shmfd->shm_object;
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
rangelock_cookie_assert(rl_cookie, RA_WLOCKED);
|
|
if (length == shmfd->shm_size)
|
|
return (0);
|
|
nobjsize = OFF_TO_IDX(length + PAGE_MASK);
|
|
|
|
/* Are we shrinking? If so, trim the end. */
|
|
if (length < shmfd->shm_size) {
|
|
if ((shmfd->shm_seals & F_SEAL_SHRINK) != 0)
|
|
return (EPERM);
|
|
|
|
/*
|
|
* Disallow any requests to shrink the size if this
|
|
* object is mapped into the kernel.
|
|
*/
|
|
if (shmfd->shm_kmappings > 0)
|
|
return (EBUSY);
|
|
|
|
/*
|
|
* Zero the truncated part of the last page.
|
|
*/
|
|
base = length & PAGE_MASK;
|
|
if (base != 0) {
|
|
idx = OFF_TO_IDX(length);
|
|
retry:
|
|
m = vm_page_grab(object, idx, VM_ALLOC_NOCREAT);
|
|
if (m != NULL) {
|
|
MPASS(vm_page_all_valid(m));
|
|
} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
|
|
m = vm_page_alloc(object, idx,
|
|
VM_ALLOC_NORMAL | VM_ALLOC_WAITFAIL);
|
|
if (m == NULL)
|
|
goto retry;
|
|
vm_object_pip_add(object, 1);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
rv = vm_pager_get_pages(object, &m, 1, NULL,
|
|
NULL);
|
|
VM_OBJECT_WLOCK(object);
|
|
vm_object_pip_wakeup(object);
|
|
if (rv == VM_PAGER_OK) {
|
|
/*
|
|
* Since the page was not resident,
|
|
* and therefore not recently
|
|
* accessed, immediately enqueue it
|
|
* for asynchronous laundering. The
|
|
* current operation is not regarded
|
|
* as an access.
|
|
*/
|
|
vm_page_launder(m);
|
|
} else {
|
|
vm_page_free(m);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
return (EIO);
|
|
}
|
|
}
|
|
if (m != NULL) {
|
|
pmap_zero_page_area(m, base, PAGE_SIZE - base);
|
|
KASSERT(vm_page_all_valid(m),
|
|
("shm_dotruncate: page %p is invalid", m));
|
|
vm_page_set_dirty(m);
|
|
vm_page_xunbusy(m);
|
|
}
|
|
}
|
|
delta = IDX_TO_OFF(object->size - nobjsize);
|
|
|
|
if (nobjsize < object->size)
|
|
vm_object_page_remove(object, nobjsize, object->size,
|
|
0);
|
|
|
|
/* Free the swap accounted for shm */
|
|
swap_release_by_cred(delta, object->cred);
|
|
object->charge -= delta;
|
|
} else {
|
|
if ((shmfd->shm_seals & F_SEAL_GROW) != 0)
|
|
return (EPERM);
|
|
|
|
/* Try to reserve additional swap space. */
|
|
delta = IDX_TO_OFF(nobjsize - object->size);
|
|
if (!swap_reserve_by_cred(delta, object->cred))
|
|
return (ENOMEM);
|
|
object->charge += delta;
|
|
}
|
|
shmfd->shm_size = length;
|
|
mtx_lock(&shm_timestamp_lock);
|
|
vfs_timestamp(&shmfd->shm_ctime);
|
|
shmfd->shm_mtime = shmfd->shm_ctime;
|
|
mtx_unlock(&shm_timestamp_lock);
|
|
object->size = nobjsize;
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
shm_dotruncate(struct shmfd *shmfd, off_t length)
|
|
{
|
|
void *rl_cookie;
|
|
int error;
|
|
|
|
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
|
|
&shmfd->shm_mtx);
|
|
VM_OBJECT_WLOCK(shmfd->shm_object);
|
|
error = shm_dotruncate_locked(shmfd, length, rl_cookie);
|
|
VM_OBJECT_WUNLOCK(shmfd->shm_object);
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* shmfd object management including creation and reference counting
|
|
* routines.
|
|
*/
|
|
struct shmfd *
|
|
shm_alloc(struct ucred *ucred, mode_t mode)
|
|
{
|
|
struct shmfd *shmfd;
|
|
|
|
shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO);
|
|
shmfd->shm_size = 0;
|
|
shmfd->shm_uid = ucred->cr_uid;
|
|
shmfd->shm_gid = ucred->cr_gid;
|
|
shmfd->shm_mode = mode;
|
|
shmfd->shm_object = vm_pager_allocate(OBJT_SWAP, NULL,
|
|
shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred);
|
|
KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate"));
|
|
vfs_timestamp(&shmfd->shm_birthtime);
|
|
shmfd->shm_atime = shmfd->shm_mtime = shmfd->shm_ctime =
|
|
shmfd->shm_birthtime;
|
|
shmfd->shm_ino = alloc_unr64(&shm_ino_unr);
|
|
refcount_init(&shmfd->shm_refs, 1);
|
|
mtx_init(&shmfd->shm_mtx, "shmrl", NULL, MTX_DEF);
|
|
rangelock_init(&shmfd->shm_rl);
|
|
#ifdef MAC
|
|
mac_posixshm_init(shmfd);
|
|
mac_posixshm_create(ucred, shmfd);
|
|
#endif
|
|
|
|
return (shmfd);
|
|
}
|
|
|
|
struct shmfd *
|
|
shm_hold(struct shmfd *shmfd)
|
|
{
|
|
|
|
refcount_acquire(&shmfd->shm_refs);
|
|
return (shmfd);
|
|
}
|
|
|
|
void
|
|
shm_drop(struct shmfd *shmfd)
|
|
{
|
|
|
|
if (refcount_release(&shmfd->shm_refs)) {
|
|
#ifdef MAC
|
|
mac_posixshm_destroy(shmfd);
|
|
#endif
|
|
rangelock_destroy(&shmfd->shm_rl);
|
|
mtx_destroy(&shmfd->shm_mtx);
|
|
vm_object_deallocate(shmfd->shm_object);
|
|
free(shmfd, M_SHMFD);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Determine if the credentials have sufficient permissions for a
|
|
* specified combination of FREAD and FWRITE.
|
|
*/
|
|
int
|
|
shm_access(struct shmfd *shmfd, struct ucred *ucred, int flags)
|
|
{
|
|
accmode_t accmode;
|
|
int error;
|
|
|
|
accmode = 0;
|
|
if (flags & FREAD)
|
|
accmode |= VREAD;
|
|
if (flags & FWRITE)
|
|
accmode |= VWRITE;
|
|
mtx_lock(&shm_timestamp_lock);
|
|
error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid, shmfd->shm_gid,
|
|
accmode, ucred, NULL);
|
|
mtx_unlock(&shm_timestamp_lock);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Dictionary management. We maintain an in-kernel dictionary to map
|
|
* paths to shmfd objects. We use the FNV hash on the path to store
|
|
* the mappings in a hash table.
|
|
*/
|
|
static void
|
|
shm_init(void *arg)
|
|
{
|
|
|
|
mtx_init(&shm_timestamp_lock, "shm timestamps", NULL, MTX_DEF);
|
|
sx_init(&shm_dict_lock, "shm dictionary");
|
|
shm_dictionary = hashinit(1024, M_SHMFD, &shm_hash);
|
|
new_unrhdr64(&shm_ino_unr, 1);
|
|
shm_dev_ino = devfs_alloc_cdp_inode();
|
|
KASSERT(shm_dev_ino > 0, ("shm dev inode not initialized"));
|
|
}
|
|
SYSINIT(shm_init, SI_SUB_SYSV_SHM, SI_ORDER_ANY, shm_init, NULL);
|
|
|
|
static struct shmfd *
|
|
shm_lookup(char *path, Fnv32_t fnv)
|
|
{
|
|
struct shm_mapping *map;
|
|
|
|
LIST_FOREACH(map, SHM_HASH(fnv), sm_link) {
|
|
if (map->sm_fnv != fnv)
|
|
continue;
|
|
if (strcmp(map->sm_path, path) == 0)
|
|
return (map->sm_shmfd);
|
|
}
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
static void
|
|
shm_insert(char *path, Fnv32_t fnv, struct shmfd *shmfd)
|
|
{
|
|
struct shm_mapping *map;
|
|
|
|
map = malloc(sizeof(struct shm_mapping), M_SHMFD, M_WAITOK);
|
|
map->sm_path = path;
|
|
map->sm_fnv = fnv;
|
|
map->sm_shmfd = shm_hold(shmfd);
|
|
shmfd->shm_path = path;
|
|
LIST_INSERT_HEAD(SHM_HASH(fnv), map, sm_link);
|
|
}
|
|
|
|
static int
|
|
shm_remove(char *path, Fnv32_t fnv, struct ucred *ucred)
|
|
{
|
|
struct shm_mapping *map;
|
|
int error;
|
|
|
|
LIST_FOREACH(map, SHM_HASH(fnv), sm_link) {
|
|
if (map->sm_fnv != fnv)
|
|
continue;
|
|
if (strcmp(map->sm_path, path) == 0) {
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_unlink(ucred, map->sm_shmfd);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
error = shm_access(map->sm_shmfd, ucred,
|
|
FREAD | FWRITE);
|
|
if (error)
|
|
return (error);
|
|
map->sm_shmfd->shm_path = NULL;
|
|
LIST_REMOVE(map, sm_link);
|
|
shm_drop(map->sm_shmfd);
|
|
free(map->sm_path, M_SHMFD);
|
|
free(map, M_SHMFD);
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
return (ENOENT);
|
|
}
|
|
|
|
int
|
|
kern_shm_open2(struct thread *td, const char *userpath, int flags, mode_t mode,
|
|
int shmflags, struct filecaps *fcaps, const char *name __unused)
|
|
{
|
|
struct filedesc *fdp;
|
|
struct shmfd *shmfd;
|
|
struct file *fp;
|
|
char *path;
|
|
void *rl_cookie;
|
|
Fnv32_t fnv;
|
|
mode_t cmode;
|
|
int error, fd, initial_seals;
|
|
|
|
if ((shmflags & ~SHM_ALLOW_SEALING) != 0)
|
|
return (EINVAL);
|
|
|
|
initial_seals = F_SEAL_SEAL;
|
|
if ((shmflags & SHM_ALLOW_SEALING) != 0)
|
|
initial_seals &= ~F_SEAL_SEAL;
|
|
|
|
#ifdef CAPABILITY_MODE
|
|
/*
|
|
* shm_open(2) is only allowed for anonymous objects.
|
|
*/
|
|
if (IN_CAPABILITY_MODE(td) && (userpath != SHM_ANON))
|
|
return (ECAPMODE);
|
|
#endif
|
|
|
|
AUDIT_ARG_FFLAGS(flags);
|
|
AUDIT_ARG_MODE(mode);
|
|
|
|
if ((flags & O_ACCMODE) != O_RDONLY && (flags & O_ACCMODE) != O_RDWR)
|
|
return (EINVAL);
|
|
|
|
if ((flags & ~(O_ACCMODE | O_CREAT | O_EXCL | O_TRUNC | O_CLOEXEC)) != 0)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* Currently only F_SEAL_SEAL may be set when creating or opening shmfd.
|
|
* If the decision is made later to allow additional seals, care must be
|
|
* taken below to ensure that the seals are properly set if the shmfd
|
|
* already existed -- this currently assumes that only F_SEAL_SEAL can
|
|
* be set and doesn't take further precautions to ensure the validity of
|
|
* the seals being added with respect to current mappings.
|
|
*/
|
|
if ((initial_seals & ~F_SEAL_SEAL) != 0)
|
|
return (EINVAL);
|
|
|
|
fdp = td->td_proc->p_fd;
|
|
cmode = (mode & ~fdp->fd_cmask) & ACCESSPERMS;
|
|
|
|
/*
|
|
* shm_open(2) created shm should always have O_CLOEXEC set, as mandated
|
|
* by POSIX. We allow it to be unset here so that an in-kernel
|
|
* interface may be written as a thin layer around shm, optionally not
|
|
* setting CLOEXEC. For shm_open(2), O_CLOEXEC is set unconditionally
|
|
* in sys_shm_open() to keep this implementation compliant.
|
|
*/
|
|
error = falloc_caps(td, &fp, &fd, flags & O_CLOEXEC, fcaps);
|
|
if (error)
|
|
return (error);
|
|
|
|
/* A SHM_ANON path pointer creates an anonymous object. */
|
|
if (userpath == SHM_ANON) {
|
|
/* A read-only anonymous object is pointless. */
|
|
if ((flags & O_ACCMODE) == O_RDONLY) {
|
|
fdclose(td, fp, fd);
|
|
fdrop(fp, td);
|
|
return (EINVAL);
|
|
}
|
|
shmfd = shm_alloc(td->td_ucred, cmode);
|
|
shmfd->shm_seals = initial_seals;
|
|
} else {
|
|
error = shm_copyin_path(td, userpath, &path);
|
|
if (error != 0) {
|
|
fdclose(td, fp, fd);
|
|
fdrop(fp, td);
|
|
return (error);
|
|
}
|
|
|
|
AUDIT_ARG_UPATH1_CANON(path);
|
|
fnv = fnv_32_str(path, FNV1_32_INIT);
|
|
sx_xlock(&shm_dict_lock);
|
|
shmfd = shm_lookup(path, fnv);
|
|
if (shmfd == NULL) {
|
|
/* Object does not yet exist, create it if requested. */
|
|
if (flags & O_CREAT) {
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_create(td->td_ucred,
|
|
path);
|
|
if (error == 0) {
|
|
#endif
|
|
shmfd = shm_alloc(td->td_ucred, cmode);
|
|
shmfd->shm_seals = initial_seals;
|
|
shm_insert(path, fnv, shmfd);
|
|
#ifdef MAC
|
|
}
|
|
#endif
|
|
} else {
|
|
free(path, M_SHMFD);
|
|
error = ENOENT;
|
|
}
|
|
} else {
|
|
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
|
|
&shmfd->shm_mtx);
|
|
|
|
/*
|
|
* kern_shm_open() likely shouldn't ever error out on
|
|
* trying to set a seal that already exists, unlike
|
|
* F_ADD_SEALS. This would break terribly as
|
|
* shm_open(2) actually sets F_SEAL_SEAL to maintain
|
|
* historical behavior where the underlying file could
|
|
* not be sealed.
|
|
*/
|
|
initial_seals &= ~shmfd->shm_seals;
|
|
|
|
/*
|
|
* Object already exists, obtain a new
|
|
* reference if requested and permitted.
|
|
*/
|
|
free(path, M_SHMFD);
|
|
|
|
/*
|
|
* initial_seals can't set additional seals if we've
|
|
* already been set F_SEAL_SEAL. If F_SEAL_SEAL is set,
|
|
* then we've already removed that one from
|
|
* initial_seals. This is currently redundant as we
|
|
* only allow setting F_SEAL_SEAL at creation time, but
|
|
* it's cheap to check and decreases the effort required
|
|
* to allow additional seals.
|
|
*/
|
|
if ((shmfd->shm_seals & F_SEAL_SEAL) != 0 &&
|
|
initial_seals != 0)
|
|
error = EPERM;
|
|
else if ((flags & (O_CREAT | O_EXCL)) ==
|
|
(O_CREAT | O_EXCL))
|
|
error = EEXIST;
|
|
else {
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_open(td->td_ucred,
|
|
shmfd, FFLAGS(flags & O_ACCMODE));
|
|
if (error == 0)
|
|
#endif
|
|
error = shm_access(shmfd, td->td_ucred,
|
|
FFLAGS(flags & O_ACCMODE));
|
|
}
|
|
|
|
/*
|
|
* Truncate the file back to zero length if
|
|
* O_TRUNC was specified and the object was
|
|
* opened with read/write.
|
|
*/
|
|
if (error == 0 &&
|
|
(flags & (O_ACCMODE | O_TRUNC)) ==
|
|
(O_RDWR | O_TRUNC)) {
|
|
VM_OBJECT_WLOCK(shmfd->shm_object);
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_truncate(
|
|
td->td_ucred, fp->f_cred, shmfd);
|
|
if (error == 0)
|
|
#endif
|
|
error = shm_dotruncate_locked(shmfd, 0,
|
|
rl_cookie);
|
|
VM_OBJECT_WUNLOCK(shmfd->shm_object);
|
|
}
|
|
if (error == 0) {
|
|
/*
|
|
* Currently we only allow F_SEAL_SEAL to be
|
|
* set initially. As noted above, this would
|
|
* need to be reworked should that change.
|
|
*/
|
|
shmfd->shm_seals |= initial_seals;
|
|
shm_hold(shmfd);
|
|
}
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie,
|
|
&shmfd->shm_mtx);
|
|
}
|
|
sx_xunlock(&shm_dict_lock);
|
|
|
|
if (error) {
|
|
fdclose(td, fp, fd);
|
|
fdrop(fp, td);
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
finit(fp, FFLAGS(flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops);
|
|
|
|
td->td_retval[0] = fd;
|
|
fdrop(fp, td);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* System calls. */
|
|
#ifdef COMPAT_FREEBSD12
|
|
int
|
|
freebsd12_shm_open(struct thread *td, struct freebsd12_shm_open_args *uap)
|
|
{
|
|
|
|
return (kern_shm_open(td, uap->path, uap->flags | O_CLOEXEC,
|
|
uap->mode, NULL));
|
|
}
|
|
#endif
|
|
|
|
int
|
|
sys_shm_unlink(struct thread *td, struct shm_unlink_args *uap)
|
|
{
|
|
char *path;
|
|
Fnv32_t fnv;
|
|
int error;
|
|
|
|
error = shm_copyin_path(td, uap->path, &path);
|
|
if (error != 0)
|
|
return (error);
|
|
|
|
AUDIT_ARG_UPATH1_CANON(path);
|
|
fnv = fnv_32_str(path, FNV1_32_INIT);
|
|
sx_xlock(&shm_dict_lock);
|
|
error = shm_remove(path, fnv, td->td_ucred);
|
|
sx_xunlock(&shm_dict_lock);
|
|
free(path, M_SHMFD);
|
|
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
sys_shm_rename(struct thread *td, struct shm_rename_args *uap)
|
|
{
|
|
char *path_from = NULL, *path_to = NULL;
|
|
Fnv32_t fnv_from, fnv_to;
|
|
struct shmfd *fd_from;
|
|
struct shmfd *fd_to;
|
|
int error;
|
|
int flags;
|
|
|
|
flags = uap->flags;
|
|
AUDIT_ARG_FFLAGS(flags);
|
|
|
|
/*
|
|
* Make sure the user passed only valid flags.
|
|
* If you add a new flag, please add a new term here.
|
|
*/
|
|
if ((flags & ~(
|
|
SHM_RENAME_NOREPLACE |
|
|
SHM_RENAME_EXCHANGE
|
|
)) != 0) {
|
|
error = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* EXCHANGE and NOREPLACE don't quite make sense together. Let's
|
|
* force the user to choose one or the other.
|
|
*/
|
|
if ((flags & SHM_RENAME_NOREPLACE) != 0 &&
|
|
(flags & SHM_RENAME_EXCHANGE) != 0) {
|
|
error = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* Renaming to or from anonymous makes no sense */
|
|
if (uap->path_from == SHM_ANON || uap->path_to == SHM_ANON) {
|
|
error = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
error = shm_copyin_path(td, uap->path_from, &path_from);
|
|
if (error != 0)
|
|
goto out;
|
|
|
|
error = shm_copyin_path(td, uap->path_to, &path_to);
|
|
if (error != 0)
|
|
goto out;
|
|
|
|
AUDIT_ARG_UPATH1_CANON(path_from);
|
|
AUDIT_ARG_UPATH2_CANON(path_to);
|
|
|
|
/* Rename with from/to equal is a no-op */
|
|
if (strcmp(path_from, path_to) == 0)
|
|
goto out;
|
|
|
|
fnv_from = fnv_32_str(path_from, FNV1_32_INIT);
|
|
fnv_to = fnv_32_str(path_to, FNV1_32_INIT);
|
|
|
|
sx_xlock(&shm_dict_lock);
|
|
|
|
fd_from = shm_lookup(path_from, fnv_from);
|
|
if (fd_from == NULL) {
|
|
error = ENOENT;
|
|
goto out_locked;
|
|
}
|
|
|
|
fd_to = shm_lookup(path_to, fnv_to);
|
|
if ((flags & SHM_RENAME_NOREPLACE) != 0 && fd_to != NULL) {
|
|
error = EEXIST;
|
|
goto out_locked;
|
|
}
|
|
|
|
/*
|
|
* Unconditionally prevents shm_remove from invalidating the 'from'
|
|
* shm's state.
|
|
*/
|
|
shm_hold(fd_from);
|
|
error = shm_remove(path_from, fnv_from, td->td_ucred);
|
|
|
|
/*
|
|
* One of my assumptions failed if ENOENT (e.g. locking didn't
|
|
* protect us)
|
|
*/
|
|
KASSERT(error != ENOENT, ("Our shm disappeared during shm_rename: %s",
|
|
path_from));
|
|
if (error != 0) {
|
|
shm_drop(fd_from);
|
|
goto out_locked;
|
|
}
|
|
|
|
/*
|
|
* If we are exchanging, we need to ensure the shm_remove below
|
|
* doesn't invalidate the dest shm's state.
|
|
*/
|
|
if ((flags & SHM_RENAME_EXCHANGE) != 0 && fd_to != NULL)
|
|
shm_hold(fd_to);
|
|
|
|
/*
|
|
* NOTE: if path_to is not already in the hash, c'est la vie;
|
|
* it simply means we have nothing already at path_to to unlink.
|
|
* That is the ENOENT case.
|
|
*
|
|
* If we somehow don't have access to unlink this guy, but
|
|
* did for the shm at path_from, then relink the shm to path_from
|
|
* and abort with EACCES.
|
|
*
|
|
* All other errors: that is weird; let's relink and abort the
|
|
* operation.
|
|
*/
|
|
error = shm_remove(path_to, fnv_to, td->td_ucred);
|
|
if (error != 0 && error != ENOENT) {
|
|
shm_insert(path_from, fnv_from, fd_from);
|
|
shm_drop(fd_from);
|
|
/* Don't free path_from now, since the hash references it */
|
|
path_from = NULL;
|
|
goto out_locked;
|
|
}
|
|
|
|
error = 0;
|
|
|
|
shm_insert(path_to, fnv_to, fd_from);
|
|
|
|
/* Don't free path_to now, since the hash references it */
|
|
path_to = NULL;
|
|
|
|
/* We kept a ref when we removed, and incremented again in insert */
|
|
shm_drop(fd_from);
|
|
KASSERT(fd_from->shm_refs > 0, ("Expected >0 refs; got: %d\n",
|
|
fd_from->shm_refs));
|
|
|
|
if ((flags & SHM_RENAME_EXCHANGE) != 0 && fd_to != NULL) {
|
|
shm_insert(path_from, fnv_from, fd_to);
|
|
path_from = NULL;
|
|
shm_drop(fd_to);
|
|
KASSERT(fd_to->shm_refs > 0, ("Expected >0 refs; got: %d\n",
|
|
fd_to->shm_refs));
|
|
}
|
|
|
|
out_locked:
|
|
sx_xunlock(&shm_dict_lock);
|
|
|
|
out:
|
|
free(path_from, M_SHMFD);
|
|
free(path_to, M_SHMFD);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
shm_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t objsize,
|
|
vm_prot_t prot, vm_prot_t cap_maxprot, int flags,
|
|
vm_ooffset_t foff, struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
vm_prot_t maxprot;
|
|
int error;
|
|
bool writecnt;
|
|
void *rl_cookie;
|
|
|
|
shmfd = fp->f_data;
|
|
maxprot = VM_PROT_NONE;
|
|
|
|
rl_cookie = rangelock_rlock(&shmfd->shm_rl, 0, objsize,
|
|
&shmfd->shm_mtx);
|
|
/* FREAD should always be set. */
|
|
if ((fp->f_flag & FREAD) != 0)
|
|
maxprot |= VM_PROT_EXECUTE | VM_PROT_READ;
|
|
|
|
/*
|
|
* If FWRITE's set, we can allow VM_PROT_WRITE unless it's a shared
|
|
* mapping with a write seal applied. Private mappings are always
|
|
* writeable.
|
|
*/
|
|
if ((flags & MAP_SHARED) == 0) {
|
|
cap_maxprot |= VM_PROT_WRITE;
|
|
maxprot |= VM_PROT_WRITE;
|
|
writecnt = false;
|
|
} else {
|
|
if ((fp->f_flag & FWRITE) != 0 &&
|
|
(shmfd->shm_seals & F_SEAL_WRITE) == 0)
|
|
maxprot |= VM_PROT_WRITE;
|
|
|
|
/*
|
|
* Any mappings from a writable descriptor may be upgraded to
|
|
* VM_PROT_WRITE with mprotect(2), unless a write-seal was
|
|
* applied between the open and subsequent mmap(2). We want to
|
|
* reject application of a write seal as long as any such
|
|
* mapping exists so that the seal cannot be trivially bypassed.
|
|
*/
|
|
writecnt = (maxprot & VM_PROT_WRITE) != 0;
|
|
if (!writecnt && (prot & VM_PROT_WRITE) != 0) {
|
|
error = EACCES;
|
|
goto out;
|
|
}
|
|
}
|
|
maxprot &= cap_maxprot;
|
|
|
|
/* See comment in vn_mmap(). */
|
|
if (
|
|
#ifdef _LP64
|
|
objsize > OFF_MAX ||
|
|
#endif
|
|
foff < 0 || foff > OFF_MAX - objsize) {
|
|
error = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_mmap(td->td_ucred, shmfd, prot, flags);
|
|
if (error != 0)
|
|
goto out;
|
|
#endif
|
|
|
|
mtx_lock(&shm_timestamp_lock);
|
|
vfs_timestamp(&shmfd->shm_atime);
|
|
mtx_unlock(&shm_timestamp_lock);
|
|
vm_object_reference(shmfd->shm_object);
|
|
|
|
if (writecnt)
|
|
vm_pager_update_writecount(shmfd->shm_object, 0, objsize);
|
|
error = vm_mmap_object(map, addr, objsize, prot, maxprot, flags,
|
|
shmfd->shm_object, foff, writecnt, td);
|
|
if (error != 0) {
|
|
if (writecnt)
|
|
vm_pager_release_writecount(shmfd->shm_object, 0,
|
|
objsize);
|
|
vm_object_deallocate(shmfd->shm_object);
|
|
}
|
|
out:
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
shm_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
int error;
|
|
|
|
error = 0;
|
|
shmfd = fp->f_data;
|
|
mtx_lock(&shm_timestamp_lock);
|
|
/*
|
|
* SUSv4 says that x bits of permission need not be affected.
|
|
* Be consistent with our shm_open there.
|
|
*/
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_setmode(active_cred, shmfd, mode);
|
|
if (error != 0)
|
|
goto out;
|
|
#endif
|
|
error = vaccess(VREG, shmfd->shm_mode, shmfd->shm_uid,
|
|
shmfd->shm_gid, VADMIN, active_cred, NULL);
|
|
if (error != 0)
|
|
goto out;
|
|
shmfd->shm_mode = mode & ACCESSPERMS;
|
|
out:
|
|
mtx_unlock(&shm_timestamp_lock);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
shm_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct shmfd *shmfd;
|
|
int error;
|
|
|
|
error = 0;
|
|
shmfd = fp->f_data;
|
|
mtx_lock(&shm_timestamp_lock);
|
|
#ifdef MAC
|
|
error = mac_posixshm_check_setowner(active_cred, shmfd, uid, gid);
|
|
if (error != 0)
|
|
goto out;
|
|
#endif
|
|
if (uid == (uid_t)-1)
|
|
uid = shmfd->shm_uid;
|
|
if (gid == (gid_t)-1)
|
|
gid = shmfd->shm_gid;
|
|
if (((uid != shmfd->shm_uid && uid != active_cred->cr_uid) ||
|
|
(gid != shmfd->shm_gid && !groupmember(gid, active_cred))) &&
|
|
(error = priv_check_cred(active_cred, PRIV_VFS_CHOWN)))
|
|
goto out;
|
|
shmfd->shm_uid = uid;
|
|
shmfd->shm_gid = gid;
|
|
out:
|
|
mtx_unlock(&shm_timestamp_lock);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Helper routines to allow the backing object of a shared memory file
|
|
* descriptor to be mapped in the kernel.
|
|
*/
|
|
int
|
|
shm_map(struct file *fp, size_t size, off_t offset, void **memp)
|
|
{
|
|
struct shmfd *shmfd;
|
|
vm_offset_t kva, ofs;
|
|
vm_object_t obj;
|
|
int rv;
|
|
|
|
if (fp->f_type != DTYPE_SHM)
|
|
return (EINVAL);
|
|
shmfd = fp->f_data;
|
|
obj = shmfd->shm_object;
|
|
VM_OBJECT_WLOCK(obj);
|
|
/*
|
|
* XXXRW: This validation is probably insufficient, and subject to
|
|
* sign errors. It should be fixed.
|
|
*/
|
|
if (offset >= shmfd->shm_size ||
|
|
offset + size > round_page(shmfd->shm_size)) {
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
return (EINVAL);
|
|
}
|
|
|
|
shmfd->shm_kmappings++;
|
|
vm_object_reference_locked(obj);
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
|
|
/* Map the object into the kernel_map and wire it. */
|
|
kva = vm_map_min(kernel_map);
|
|
ofs = offset & PAGE_MASK;
|
|
offset = trunc_page(offset);
|
|
size = round_page(size + ofs);
|
|
rv = vm_map_find(kernel_map, obj, offset, &kva, size, 0,
|
|
VMFS_OPTIMAL_SPACE, VM_PROT_READ | VM_PROT_WRITE,
|
|
VM_PROT_READ | VM_PROT_WRITE, 0);
|
|
if (rv == KERN_SUCCESS) {
|
|
rv = vm_map_wire(kernel_map, kva, kva + size,
|
|
VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
|
|
if (rv == KERN_SUCCESS) {
|
|
*memp = (void *)(kva + ofs);
|
|
return (0);
|
|
}
|
|
vm_map_remove(kernel_map, kva, kva + size);
|
|
} else
|
|
vm_object_deallocate(obj);
|
|
|
|
/* On failure, drop our mapping reference. */
|
|
VM_OBJECT_WLOCK(obj);
|
|
shmfd->shm_kmappings--;
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
|
|
return (vm_mmap_to_errno(rv));
|
|
}
|
|
|
|
/*
|
|
* We require the caller to unmap the entire entry. This allows us to
|
|
* safely decrement shm_kmappings when a mapping is removed.
|
|
*/
|
|
int
|
|
shm_unmap(struct file *fp, void *mem, size_t size)
|
|
{
|
|
struct shmfd *shmfd;
|
|
vm_map_entry_t entry;
|
|
vm_offset_t kva, ofs;
|
|
vm_object_t obj;
|
|
vm_pindex_t pindex;
|
|
vm_prot_t prot;
|
|
boolean_t wired;
|
|
vm_map_t map;
|
|
int rv;
|
|
|
|
if (fp->f_type != DTYPE_SHM)
|
|
return (EINVAL);
|
|
shmfd = fp->f_data;
|
|
kva = (vm_offset_t)mem;
|
|
ofs = kva & PAGE_MASK;
|
|
kva = trunc_page(kva);
|
|
size = round_page(size + ofs);
|
|
map = kernel_map;
|
|
rv = vm_map_lookup(&map, kva, VM_PROT_READ | VM_PROT_WRITE, &entry,
|
|
&obj, &pindex, &prot, &wired);
|
|
if (rv != KERN_SUCCESS)
|
|
return (EINVAL);
|
|
if (entry->start != kva || entry->end != kva + size) {
|
|
vm_map_lookup_done(map, entry);
|
|
return (EINVAL);
|
|
}
|
|
vm_map_lookup_done(map, entry);
|
|
if (obj != shmfd->shm_object)
|
|
return (EINVAL);
|
|
vm_map_remove(map, kva, kva + size);
|
|
VM_OBJECT_WLOCK(obj);
|
|
KASSERT(shmfd->shm_kmappings > 0, ("shm_unmap: object not mapped"));
|
|
shmfd->shm_kmappings--;
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
shm_fill_kinfo_locked(struct shmfd *shmfd, struct kinfo_file *kif, bool list)
|
|
{
|
|
const char *path, *pr_path;
|
|
size_t pr_pathlen;
|
|
bool visible;
|
|
|
|
sx_assert(&shm_dict_lock, SA_LOCKED);
|
|
kif->kf_type = KF_TYPE_SHM;
|
|
kif->kf_un.kf_file.kf_file_mode = S_IFREG | shmfd->shm_mode;
|
|
kif->kf_un.kf_file.kf_file_size = shmfd->shm_size;
|
|
if (shmfd->shm_path != NULL) {
|
|
if (shmfd->shm_path != NULL) {
|
|
path = shmfd->shm_path;
|
|
pr_path = curthread->td_ucred->cr_prison->pr_path;
|
|
if (strcmp(pr_path, "/") != 0) {
|
|
/* Return the jail-rooted pathname. */
|
|
pr_pathlen = strlen(pr_path);
|
|
visible = strncmp(path, pr_path, pr_pathlen)
|
|
== 0 && path[pr_pathlen] == '/';
|
|
if (list && !visible)
|
|
return (EPERM);
|
|
if (visible)
|
|
path += pr_pathlen;
|
|
}
|
|
strlcpy(kif->kf_path, path, sizeof(kif->kf_path));
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
shm_fill_kinfo(struct file *fp, struct kinfo_file *kif,
|
|
struct filedesc *fdp __unused)
|
|
{
|
|
int res;
|
|
|
|
sx_slock(&shm_dict_lock);
|
|
res = shm_fill_kinfo_locked(fp->f_data, kif, false);
|
|
sx_sunlock(&shm_dict_lock);
|
|
return (res);
|
|
}
|
|
|
|
static int
|
|
shm_add_seals(struct file *fp, int seals)
|
|
{
|
|
struct shmfd *shmfd;
|
|
void *rl_cookie;
|
|
vm_ooffset_t writemappings;
|
|
int error, nseals;
|
|
|
|
error = 0;
|
|
shmfd = fp->f_data;
|
|
rl_cookie = rangelock_wlock(&shmfd->shm_rl, 0, OFF_MAX,
|
|
&shmfd->shm_mtx);
|
|
|
|
/* Even already-set seals should result in EPERM. */
|
|
if ((shmfd->shm_seals & F_SEAL_SEAL) != 0) {
|
|
error = EPERM;
|
|
goto out;
|
|
}
|
|
nseals = seals & ~shmfd->shm_seals;
|
|
if ((nseals & F_SEAL_WRITE) != 0) {
|
|
/*
|
|
* The rangelock above prevents writable mappings from being
|
|
* added after we've started applying seals. The RLOCK here
|
|
* is to avoid torn reads on ILP32 arches as unmapping/reducing
|
|
* writemappings will be done without a rangelock.
|
|
*/
|
|
VM_OBJECT_RLOCK(shmfd->shm_object);
|
|
writemappings = shmfd->shm_object->un_pager.swp.writemappings;
|
|
VM_OBJECT_RUNLOCK(shmfd->shm_object);
|
|
/* kmappings are also writable */
|
|
if (writemappings > 0) {
|
|
error = EBUSY;
|
|
goto out;
|
|
}
|
|
}
|
|
shmfd->shm_seals |= nseals;
|
|
out:
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
shm_get_seals(struct file *fp, int *seals)
|
|
{
|
|
struct shmfd *shmfd;
|
|
|
|
shmfd = fp->f_data;
|
|
*seals = shmfd->shm_seals;
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
shm_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td)
|
|
{
|
|
void *rl_cookie;
|
|
struct shmfd *shmfd;
|
|
size_t size;
|
|
int error;
|
|
|
|
/* This assumes that the caller already checked for overflow. */
|
|
error = 0;
|
|
shmfd = fp->f_data;
|
|
size = offset + len;
|
|
|
|
/*
|
|
* Just grab the rangelock for the range that we may be attempting to
|
|
* grow, rather than blocking read/write for regions we won't be
|
|
* touching while this (potential) resize is in progress. Other
|
|
* attempts to resize the shmfd will have to take a write lock from 0 to
|
|
* OFF_MAX, so this being potentially beyond the current usable range of
|
|
* the shmfd is not necessarily a concern. If other mechanisms are
|
|
* added to grow a shmfd, this may need to be re-evaluated.
|
|
*/
|
|
rl_cookie = rangelock_wlock(&shmfd->shm_rl, offset, size,
|
|
&shmfd->shm_mtx);
|
|
if (size > shmfd->shm_size) {
|
|
VM_OBJECT_WLOCK(shmfd->shm_object);
|
|
error = shm_dotruncate_locked(shmfd, size, rl_cookie);
|
|
VM_OBJECT_WUNLOCK(shmfd->shm_object);
|
|
}
|
|
rangelock_unlock(&shmfd->shm_rl, rl_cookie, &shmfd->shm_mtx);
|
|
/* Translate to posix_fallocate(2) return value as needed. */
|
|
if (error == ENOMEM)
|
|
error = ENOSPC;
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
sysctl_posix_shm_list(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct shm_mapping *shmm;
|
|
struct sbuf sb;
|
|
struct kinfo_file kif;
|
|
u_long i;
|
|
ssize_t curlen;
|
|
int error, error2;
|
|
|
|
sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_file) * 5, req);
|
|
sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
|
|
curlen = 0;
|
|
error = 0;
|
|
sx_slock(&shm_dict_lock);
|
|
for (i = 0; i < shm_hash + 1; i++) {
|
|
LIST_FOREACH(shmm, &shm_dictionary[i], sm_link) {
|
|
error = shm_fill_kinfo_locked(shmm->sm_shmfd,
|
|
&kif, true);
|
|
if (error == EPERM)
|
|
continue;
|
|
if (error != 0)
|
|
break;
|
|
pack_kinfo(&kif);
|
|
if (req->oldptr != NULL &&
|
|
kif.kf_structsize + curlen > req->oldlen)
|
|
break;
|
|
error = sbuf_bcat(&sb, &kif, kif.kf_structsize) == 0 ?
|
|
0 : ENOMEM;
|
|
if (error != 0)
|
|
break;
|
|
curlen += kif.kf_structsize;
|
|
}
|
|
}
|
|
sx_sunlock(&shm_dict_lock);
|
|
error2 = sbuf_finish(&sb);
|
|
sbuf_delete(&sb);
|
|
return (error != 0 ? error : error2);
|
|
}
|
|
|
|
SYSCTL_PROC(_kern_ipc, OID_AUTO, posix_shm_list,
|
|
CTLFLAG_RD | CTLFLAG_MPSAFE | CTLTYPE_OPAQUE,
|
|
NULL, 0, sysctl_posix_shm_list, "",
|
|
"POSIX SHM list");
|
|
|
|
int
|
|
kern_shm_open(struct thread *td, const char *path, int flags, mode_t mode,
|
|
struct filecaps *caps)
|
|
{
|
|
|
|
return (kern_shm_open2(td, path, flags, mode, 0, caps, NULL));
|
|
}
|
|
|
|
/*
|
|
* This version of the shm_open() interface leaves CLOEXEC behavior up to the
|
|
* caller, and libc will enforce it for the traditional shm_open() call. This
|
|
* allows other consumers, like memfd_create(), to opt-in for CLOEXEC. This
|
|
* interface also includes a 'name' argument that is currently unused, but could
|
|
* potentially be exported later via some interface for debugging purposes.
|
|
* From the kernel's perspective, it is optional. Individual consumers like
|
|
* memfd_create() may require it in order to be compatible with other systems
|
|
* implementing the same function.
|
|
*/
|
|
int
|
|
sys_shm_open2(struct thread *td, struct shm_open2_args *uap)
|
|
{
|
|
|
|
return (kern_shm_open2(td, uap->path, uap->flags, uap->mode,
|
|
uap->shmflags, NULL, uap->name));
|
|
}
|