b2ca400b88
CloudABI processes should run in capabilities mode automatically. There is no need to switch manually (e.g., by calling cap_enter()). Add a flag, SV_CAPSICUM, that can be used to call into cap_enter() during execve(). Reviewed by: kib
1596 lines
39 KiB
C
1596 lines
39 KiB
C
/*-
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* Copyright (c) 1993, David Greenman
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* All rights reserved.
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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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_capsicum.h"
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#include "opt_hwpmc_hooks.h"
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#include "opt_ktrace.h"
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#include "opt_vm.h"
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#include <sys/param.h>
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#include <sys/capsicum.h>
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#include <sys/systm.h>
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#include <sys/eventhandler.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sysproto.h>
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#include <sys/signalvar.h>
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#include <sys/kernel.h>
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#include <sys/mount.h>
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#include <sys/filedesc.h>
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#include <sys/fcntl.h>
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#include <sys/acct.h>
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#include <sys/exec.h>
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#include <sys/imgact.h>
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#include <sys/imgact_elf.h>
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#include <sys/wait.h>
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#include <sys/malloc.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/pioctl.h>
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#include <sys/namei.h>
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#include <sys/resourcevar.h>
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#include <sys/rwlock.h>
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#include <sys/sched.h>
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#include <sys/sdt.h>
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#include <sys/sf_buf.h>
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#include <sys/syscallsubr.h>
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#include <sys/sysent.h>
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#include <sys/shm.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <sys/stat.h>
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#ifdef KTRACE
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#include <sys/ktrace.h>
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#endif
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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_page.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_extern.h>
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#include <vm/vm_object.h>
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#include <vm/vm_pager.h>
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|
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#ifdef HWPMC_HOOKS
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#include <sys/pmckern.h>
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#endif
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#include <machine/reg.h>
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#include <security/audit/audit.h>
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#include <security/mac/mac_framework.h>
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|
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#ifdef KDTRACE_HOOKS
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#include <sys/dtrace_bsd.h>
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dtrace_execexit_func_t dtrace_fasttrap_exec;
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#endif
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|
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SDT_PROVIDER_DECLARE(proc);
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SDT_PROBE_DEFINE1(proc, kernel, , exec, "char *");
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SDT_PROBE_DEFINE1(proc, kernel, , exec__failure, "int");
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SDT_PROBE_DEFINE1(proc, kernel, , exec__success, "char *");
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MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
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|
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static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
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static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
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static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
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static int do_execve(struct thread *td, struct image_args *args,
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struct mac *mac_p);
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|
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/* XXX This should be vm_size_t. */
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SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
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NULL, 0, sysctl_kern_ps_strings, "LU", "");
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/* XXX This should be vm_size_t. */
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SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD|
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CTLFLAG_CAPRD, NULL, 0, sysctl_kern_usrstack, "LU", "");
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SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
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NULL, 0, sysctl_kern_stackprot, "I", "");
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u_long ps_arg_cache_limit = PAGE_SIZE / 16;
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SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
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&ps_arg_cache_limit, 0, "");
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static int disallow_high_osrel;
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SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW,
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&disallow_high_osrel, 0,
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"Disallow execution of binaries built for higher version of the world");
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static int map_at_zero = 0;
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SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0,
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"Permit processes to map an object at virtual address 0.");
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static int
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sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
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{
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struct proc *p;
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int error;
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p = curproc;
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#ifdef SCTL_MASK32
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if (req->flags & SCTL_MASK32) {
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unsigned int val;
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val = (unsigned int)p->p_sysent->sv_psstrings;
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error = SYSCTL_OUT(req, &val, sizeof(val));
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} else
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#endif
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error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
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sizeof(p->p_sysent->sv_psstrings));
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return error;
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}
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static int
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sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
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{
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struct proc *p;
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int error;
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p = curproc;
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#ifdef SCTL_MASK32
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if (req->flags & SCTL_MASK32) {
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unsigned int val;
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val = (unsigned int)p->p_sysent->sv_usrstack;
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error = SYSCTL_OUT(req, &val, sizeof(val));
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} else
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#endif
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error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
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sizeof(p->p_sysent->sv_usrstack));
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return error;
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}
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static int
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sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
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{
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struct proc *p;
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p = curproc;
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return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
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sizeof(p->p_sysent->sv_stackprot)));
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}
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/*
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* Each of the items is a pointer to a `const struct execsw', hence the
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* double pointer here.
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*/
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static const struct execsw **execsw;
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#ifndef _SYS_SYSPROTO_H_
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struct execve_args {
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char *fname;
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char **argv;
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char **envv;
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};
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#endif
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int
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sys_execve(struct thread *td, struct execve_args *uap)
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{
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struct image_args args;
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struct vmspace *oldvmspace;
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int error;
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error = pre_execve(td, &oldvmspace);
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if (error != 0)
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return (error);
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error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
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uap->argv, uap->envv);
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if (error == 0)
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error = kern_execve(td, &args, NULL);
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post_execve(td, error, oldvmspace);
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return (error);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct fexecve_args {
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int fd;
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char **argv;
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char **envv;
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}
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#endif
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int
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sys_fexecve(struct thread *td, struct fexecve_args *uap)
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{
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struct image_args args;
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struct vmspace *oldvmspace;
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int error;
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error = pre_execve(td, &oldvmspace);
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if (error != 0)
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return (error);
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error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
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uap->argv, uap->envv);
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if (error == 0) {
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args.fd = uap->fd;
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error = kern_execve(td, &args, NULL);
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}
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post_execve(td, error, oldvmspace);
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return (error);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct __mac_execve_args {
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|
char *fname;
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|
char **argv;
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|
char **envv;
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struct mac *mac_p;
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};
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#endif
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int
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sys___mac_execve(struct thread *td, struct __mac_execve_args *uap)
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{
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#ifdef MAC
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struct image_args args;
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struct vmspace *oldvmspace;
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int error;
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error = pre_execve(td, &oldvmspace);
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if (error != 0)
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return (error);
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error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
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uap->argv, uap->envv);
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if (error == 0)
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error = kern_execve(td, &args, uap->mac_p);
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post_execve(td, error, oldvmspace);
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return (error);
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#else
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return (ENOSYS);
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#endif
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}
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|
|
int
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pre_execve(struct thread *td, struct vmspace **oldvmspace)
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{
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struct proc *p;
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int error;
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KASSERT(td == curthread, ("non-current thread %p", td));
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error = 0;
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p = td->td_proc;
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if ((p->p_flag & P_HADTHREADS) != 0) {
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PROC_LOCK(p);
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if (thread_single(p, SINGLE_BOUNDARY) != 0)
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error = ERESTART;
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PROC_UNLOCK(p);
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}
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KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0,
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("nested execve"));
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*oldvmspace = p->p_vmspace;
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return (error);
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}
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|
|
|
void
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post_execve(struct thread *td, int error, struct vmspace *oldvmspace)
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{
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struct proc *p;
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|
|
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KASSERT(td == curthread, ("non-current thread %p", td));
|
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p = td->td_proc;
|
|
if ((p->p_flag & P_HADTHREADS) != 0) {
|
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PROC_LOCK(p);
|
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/*
|
|
* If success, we upgrade to SINGLE_EXIT state to
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* force other threads to suicide.
|
|
*/
|
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if (error == 0)
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thread_single(p, SINGLE_EXIT);
|
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else
|
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thread_single_end(p, SINGLE_BOUNDARY);
|
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PROC_UNLOCK(p);
|
|
}
|
|
if ((td->td_pflags & TDP_EXECVMSPC) != 0) {
|
|
KASSERT(p->p_vmspace != oldvmspace,
|
|
("oldvmspace still used"));
|
|
vmspace_free(oldvmspace);
|
|
td->td_pflags &= ~TDP_EXECVMSPC;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* XXX: kern_execve has the astonishing property of not always returning to
|
|
* the caller. If sufficiently bad things happen during the call to
|
|
* do_execve(), it can end up calling exit1(); as a result, callers must
|
|
* avoid doing anything which they might need to undo (e.g., allocating
|
|
* memory).
|
|
*/
|
|
int
|
|
kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p)
|
|
{
|
|
|
|
AUDIT_ARG_ARGV(args->begin_argv, args->argc,
|
|
args->begin_envv - args->begin_argv);
|
|
AUDIT_ARG_ENVV(args->begin_envv, args->envc,
|
|
args->endp - args->begin_envv);
|
|
return (do_execve(td, args, mac_p));
|
|
}
|
|
|
|
/*
|
|
* In-kernel implementation of execve(). All arguments are assumed to be
|
|
* userspace pointers from the passed thread.
|
|
*/
|
|
static int
|
|
do_execve(td, args, mac_p)
|
|
struct thread *td;
|
|
struct image_args *args;
|
|
struct mac *mac_p;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct nameidata nd;
|
|
struct ucred *newcred = NULL, *oldcred;
|
|
struct uidinfo *euip = NULL;
|
|
register_t *stack_base;
|
|
int error, i;
|
|
struct image_params image_params, *imgp;
|
|
struct vattr attr;
|
|
int (*img_first)(struct image_params *);
|
|
struct pargs *oldargs = NULL, *newargs = NULL;
|
|
struct sigacts *oldsigacts, *newsigacts;
|
|
#ifdef KTRACE
|
|
struct vnode *tracevp = NULL;
|
|
struct ucred *tracecred = NULL;
|
|
#endif
|
|
struct vnode *oldtextvp = NULL, *newtextvp;
|
|
cap_rights_t rights;
|
|
int credential_changing;
|
|
int textset;
|
|
#ifdef MAC
|
|
struct label *interpvplabel = NULL;
|
|
int will_transition;
|
|
#endif
|
|
#ifdef HWPMC_HOOKS
|
|
struct pmckern_procexec pe;
|
|
#endif
|
|
static const char fexecv_proc_title[] = "(fexecv)";
|
|
|
|
imgp = &image_params;
|
|
|
|
/*
|
|
* Lock the process and set the P_INEXEC flag to indicate that
|
|
* it should be left alone until we're done here. This is
|
|
* necessary to avoid race conditions - e.g. in ptrace() -
|
|
* that might allow a local user to illicitly obtain elevated
|
|
* privileges.
|
|
*/
|
|
PROC_LOCK(p);
|
|
KASSERT((p->p_flag & P_INEXEC) == 0,
|
|
("%s(): process already has P_INEXEC flag", __func__));
|
|
p->p_flag |= P_INEXEC;
|
|
PROC_UNLOCK(p);
|
|
|
|
/*
|
|
* Initialize part of the common data
|
|
*/
|
|
bzero(imgp, sizeof(*imgp));
|
|
imgp->proc = p;
|
|
imgp->attr = &attr;
|
|
imgp->args = args;
|
|
|
|
#ifdef MAC
|
|
error = mac_execve_enter(imgp, mac_p);
|
|
if (error)
|
|
goto exec_fail;
|
|
#endif
|
|
|
|
/*
|
|
* Translate the file name. namei() returns a vnode pointer
|
|
* in ni_vp amoung other things.
|
|
*
|
|
* XXXAUDIT: It would be desirable to also audit the name of the
|
|
* interpreter if this is an interpreted binary.
|
|
*/
|
|
if (args->fname != NULL) {
|
|
NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
|
|
| AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
|
|
}
|
|
|
|
SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
|
|
|
|
interpret:
|
|
if (args->fname != NULL) {
|
|
#ifdef CAPABILITY_MODE
|
|
/*
|
|
* While capability mode can't reach this point via direct
|
|
* path arguments to execve(), we also don't allow
|
|
* interpreters to be used in capability mode (for now).
|
|
* Catch indirect lookups and return a permissions error.
|
|
*/
|
|
if (IN_CAPABILITY_MODE(td)) {
|
|
error = ECAPMODE;
|
|
goto exec_fail;
|
|
}
|
|
#endif
|
|
error = namei(&nd);
|
|
if (error)
|
|
goto exec_fail;
|
|
|
|
newtextvp = nd.ni_vp;
|
|
imgp->vp = newtextvp;
|
|
} else {
|
|
AUDIT_ARG_FD(args->fd);
|
|
/*
|
|
* Descriptors opened only with O_EXEC or O_RDONLY are allowed.
|
|
*/
|
|
error = fgetvp_exec(td, args->fd,
|
|
cap_rights_init(&rights, CAP_FEXECVE), &newtextvp);
|
|
if (error)
|
|
goto exec_fail;
|
|
vn_lock(newtextvp, LK_EXCLUSIVE | LK_RETRY);
|
|
AUDIT_ARG_VNODE1(newtextvp);
|
|
imgp->vp = newtextvp;
|
|
}
|
|
|
|
/*
|
|
* Check file permissions (also 'opens' file)
|
|
*/
|
|
error = exec_check_permissions(imgp);
|
|
if (error)
|
|
goto exec_fail_dealloc;
|
|
|
|
imgp->object = imgp->vp->v_object;
|
|
if (imgp->object != NULL)
|
|
vm_object_reference(imgp->object);
|
|
|
|
/*
|
|
* Set VV_TEXT now so no one can write to the executable while we're
|
|
* activating it.
|
|
*
|
|
* Remember if this was set before and unset it in case this is not
|
|
* actually an executable image.
|
|
*/
|
|
textset = VOP_IS_TEXT(imgp->vp);
|
|
VOP_SET_TEXT(imgp->vp);
|
|
|
|
error = exec_map_first_page(imgp);
|
|
if (error)
|
|
goto exec_fail_dealloc;
|
|
|
|
imgp->proc->p_osrel = 0;
|
|
/*
|
|
* If the current process has a special image activator it
|
|
* wants to try first, call it. For example, emulating shell
|
|
* scripts differently.
|
|
*/
|
|
error = -1;
|
|
if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
|
|
error = img_first(imgp);
|
|
|
|
/*
|
|
* Loop through the list of image activators, calling each one.
|
|
* An activator returns -1 if there is no match, 0 on success,
|
|
* and an error otherwise.
|
|
*/
|
|
for (i = 0; error == -1 && execsw[i]; ++i) {
|
|
if (execsw[i]->ex_imgact == NULL ||
|
|
execsw[i]->ex_imgact == img_first) {
|
|
continue;
|
|
}
|
|
error = (*execsw[i]->ex_imgact)(imgp);
|
|
}
|
|
|
|
if (error) {
|
|
if (error == -1) {
|
|
if (textset == 0)
|
|
VOP_UNSET_TEXT(imgp->vp);
|
|
error = ENOEXEC;
|
|
}
|
|
goto exec_fail_dealloc;
|
|
}
|
|
|
|
/*
|
|
* Special interpreter operation, cleanup and loop up to try to
|
|
* activate the interpreter.
|
|
*/
|
|
if (imgp->interpreted) {
|
|
exec_unmap_first_page(imgp);
|
|
/*
|
|
* VV_TEXT needs to be unset for scripts. There is a short
|
|
* period before we determine that something is a script where
|
|
* VV_TEXT will be set. The vnode lock is held over this
|
|
* entire period so nothing should illegitimately be blocked.
|
|
*/
|
|
VOP_UNSET_TEXT(imgp->vp);
|
|
/* free name buffer and old vnode */
|
|
if (args->fname != NULL)
|
|
NDFREE(&nd, NDF_ONLY_PNBUF);
|
|
#ifdef MAC
|
|
mac_execve_interpreter_enter(newtextvp, &interpvplabel);
|
|
#endif
|
|
if (imgp->opened) {
|
|
VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td);
|
|
imgp->opened = 0;
|
|
}
|
|
vput(newtextvp);
|
|
vm_object_deallocate(imgp->object);
|
|
imgp->object = NULL;
|
|
/* set new name to that of the interpreter */
|
|
NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
|
|
UIO_SYSSPACE, imgp->interpreter_name, td);
|
|
args->fname = imgp->interpreter_name;
|
|
goto interpret;
|
|
}
|
|
|
|
/*
|
|
* NB: We unlock the vnode here because it is believed that none
|
|
* of the sv_copyout_strings/sv_fixup operations require the vnode.
|
|
*/
|
|
VOP_UNLOCK(imgp->vp, 0);
|
|
|
|
/*
|
|
* Do the best to calculate the full path to the image file.
|
|
*/
|
|
if (imgp->auxargs != NULL &&
|
|
((args->fname != NULL && args->fname[0] == '/') ||
|
|
vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
|
|
imgp->execpath = args->fname;
|
|
|
|
if (disallow_high_osrel &&
|
|
P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) {
|
|
error = ENOEXEC;
|
|
uprintf("Osrel %d for image %s too high\n", p->p_osrel,
|
|
imgp->execpath != NULL ? imgp->execpath : "<unresolved>");
|
|
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
|
|
goto exec_fail_dealloc;
|
|
}
|
|
|
|
/* ABI enforces the use of Capsicum. Switch into capabilities mode. */
|
|
if (SV_PROC_FLAG(p, SV_CAPSICUM))
|
|
sys_cap_enter(td, NULL);
|
|
|
|
/*
|
|
* Copy out strings (args and env) and initialize stack base
|
|
*/
|
|
if (p->p_sysent->sv_copyout_strings)
|
|
stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
|
|
else
|
|
stack_base = exec_copyout_strings(imgp);
|
|
|
|
/*
|
|
* If custom stack fixup routine present for this process
|
|
* let it do the stack setup.
|
|
* Else stuff argument count as first item on stack
|
|
*/
|
|
if (p->p_sysent->sv_fixup != NULL)
|
|
(*p->p_sysent->sv_fixup)(&stack_base, imgp);
|
|
else
|
|
suword(--stack_base, imgp->args->argc);
|
|
|
|
if (args->fdp != NULL) {
|
|
/* Install a brand new file descriptor table. */
|
|
fdinstall_remapped(td, args->fdp);
|
|
args->fdp = NULL;
|
|
} else {
|
|
/*
|
|
* Keep on using the existing file descriptor table. For
|
|
* security and other reasons, the file descriptor table
|
|
* cannot be shared after an exec.
|
|
*/
|
|
fdunshare(td);
|
|
/* close files on exec */
|
|
fdcloseexec(td);
|
|
}
|
|
|
|
/*
|
|
* Malloc things before we need locks.
|
|
*/
|
|
i = imgp->args->begin_envv - imgp->args->begin_argv;
|
|
/* Cache arguments if they fit inside our allowance */
|
|
if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
|
|
newargs = pargs_alloc(i);
|
|
bcopy(imgp->args->begin_argv, newargs->ar_args, i);
|
|
}
|
|
|
|
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
|
|
|
|
/*
|
|
* For security and other reasons, signal handlers cannot
|
|
* be shared after an exec. The new process gets a copy of the old
|
|
* handlers. In execsigs(), the new process will have its signals
|
|
* reset.
|
|
*/
|
|
if (sigacts_shared(p->p_sigacts)) {
|
|
oldsigacts = p->p_sigacts;
|
|
newsigacts = sigacts_alloc();
|
|
sigacts_copy(newsigacts, oldsigacts);
|
|
} else {
|
|
oldsigacts = NULL;
|
|
newsigacts = NULL; /* satisfy gcc */
|
|
}
|
|
|
|
PROC_LOCK(p);
|
|
if (oldsigacts)
|
|
p->p_sigacts = newsigacts;
|
|
oldcred = p->p_ucred;
|
|
/* Stop profiling */
|
|
stopprofclock(p);
|
|
|
|
/* reset caught signals */
|
|
execsigs(p);
|
|
|
|
/* name this process - nameiexec(p, ndp) */
|
|
bzero(p->p_comm, sizeof(p->p_comm));
|
|
if (args->fname)
|
|
bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
|
|
min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
|
|
else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0)
|
|
bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
|
|
bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
|
|
#ifdef KTR
|
|
sched_clear_tdname(td);
|
|
#endif
|
|
|
|
/*
|
|
* mark as execed, wakeup the process that vforked (if any) and tell
|
|
* it that it now has its own resources back
|
|
*/
|
|
p->p_flag |= P_EXEC;
|
|
if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0)
|
|
p->p_flag2 &= ~P2_NOTRACE;
|
|
if (p->p_flag & P_PPWAIT) {
|
|
p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
|
|
cv_broadcast(&p->p_pwait);
|
|
}
|
|
|
|
/*
|
|
* Implement image setuid/setgid.
|
|
*
|
|
* Don't honor setuid/setgid if the filesystem prohibits it or if
|
|
* the process is being traced.
|
|
*
|
|
* We disable setuid/setgid/etc in compatibility mode on the basis
|
|
* that most setugid applications are not written with that
|
|
* environment in mind, and will therefore almost certainly operate
|
|
* incorrectly. In principle there's no reason that setugid
|
|
* applications might not be useful in capability mode, so we may want
|
|
* to reconsider this conservative design choice in the future.
|
|
*
|
|
* XXXMAC: For the time being, use NOSUID to also prohibit
|
|
* transitions on the file system.
|
|
*/
|
|
credential_changing = 0;
|
|
credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
|
|
attr.va_uid;
|
|
credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
|
|
attr.va_gid;
|
|
#ifdef MAC
|
|
will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
|
|
interpvplabel, imgp);
|
|
credential_changing |= will_transition;
|
|
#endif
|
|
|
|
if (credential_changing &&
|
|
#ifdef CAPABILITY_MODE
|
|
((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
|
|
#endif
|
|
(imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
|
|
(p->p_flag & P_TRACED) == 0) {
|
|
/*
|
|
* Turn off syscall tracing for set-id programs, except for
|
|
* root. Record any set-id flags first to make sure that
|
|
* we do not regain any tracing during a possible block.
|
|
*/
|
|
setsugid(p);
|
|
|
|
#ifdef KTRACE
|
|
if (p->p_tracecred != NULL &&
|
|
priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0))
|
|
ktrprocexec(p, &tracecred, &tracevp);
|
|
#endif
|
|
/*
|
|
* Close any file descriptors 0..2 that reference procfs,
|
|
* then make sure file descriptors 0..2 are in use.
|
|
*
|
|
* Both fdsetugidsafety() and fdcheckstd() may call functions
|
|
* taking sleepable locks, so temporarily drop our locks.
|
|
*/
|
|
PROC_UNLOCK(p);
|
|
VOP_UNLOCK(imgp->vp, 0);
|
|
fdsetugidsafety(td);
|
|
error = fdcheckstd(td);
|
|
if (error != 0)
|
|
goto done1;
|
|
newcred = crdup(oldcred);
|
|
euip = uifind(attr.va_uid);
|
|
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
|
|
PROC_LOCK(p);
|
|
/*
|
|
* Set the new credentials.
|
|
*/
|
|
if (attr.va_mode & S_ISUID)
|
|
change_euid(newcred, euip);
|
|
if (attr.va_mode & S_ISGID)
|
|
change_egid(newcred, attr.va_gid);
|
|
#ifdef MAC
|
|
if (will_transition) {
|
|
mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
|
|
interpvplabel, imgp);
|
|
}
|
|
#endif
|
|
/*
|
|
* Implement correct POSIX saved-id behavior.
|
|
*
|
|
* XXXMAC: Note that the current logic will save the
|
|
* uid and gid if a MAC domain transition occurs, even
|
|
* though maybe it shouldn't.
|
|
*/
|
|
change_svuid(newcred, newcred->cr_uid);
|
|
change_svgid(newcred, newcred->cr_gid);
|
|
proc_set_cred(p, newcred);
|
|
} else {
|
|
if (oldcred->cr_uid == oldcred->cr_ruid &&
|
|
oldcred->cr_gid == oldcred->cr_rgid)
|
|
p->p_flag &= ~P_SUGID;
|
|
/*
|
|
* Implement correct POSIX saved-id behavior.
|
|
*
|
|
* XXX: It's not clear that the existing behavior is
|
|
* POSIX-compliant. A number of sources indicate that the
|
|
* saved uid/gid should only be updated if the new ruid is
|
|
* not equal to the old ruid, or the new euid is not equal
|
|
* to the old euid and the new euid is not equal to the old
|
|
* ruid. The FreeBSD code always updates the saved uid/gid.
|
|
* Also, this code uses the new (replaced) euid and egid as
|
|
* the source, which may or may not be the right ones to use.
|
|
*/
|
|
if (oldcred->cr_svuid != oldcred->cr_uid ||
|
|
oldcred->cr_svgid != oldcred->cr_gid) {
|
|
PROC_UNLOCK(p);
|
|
VOP_UNLOCK(imgp->vp, 0);
|
|
newcred = crdup(oldcred);
|
|
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
|
|
PROC_LOCK(p);
|
|
change_svuid(newcred, newcred->cr_uid);
|
|
change_svgid(newcred, newcred->cr_gid);
|
|
proc_set_cred(p, newcred);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Store the vp for use in procfs. This vnode was referenced by namei
|
|
* or fgetvp_exec.
|
|
*/
|
|
oldtextvp = p->p_textvp;
|
|
p->p_textvp = newtextvp;
|
|
|
|
#ifdef KDTRACE_HOOKS
|
|
/*
|
|
* Tell the DTrace fasttrap provider about the exec if it
|
|
* has declared an interest.
|
|
*/
|
|
if (dtrace_fasttrap_exec)
|
|
dtrace_fasttrap_exec(p);
|
|
#endif
|
|
|
|
/*
|
|
* Notify others that we exec'd, and clear the P_INEXEC flag
|
|
* as we're now a bona fide freshly-execed process.
|
|
*/
|
|
KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
|
|
p->p_flag &= ~P_INEXEC;
|
|
|
|
/* clear "fork but no exec" flag, as we _are_ execing */
|
|
p->p_acflag &= ~AFORK;
|
|
|
|
/*
|
|
* Free any previous argument cache and replace it with
|
|
* the new argument cache, if any.
|
|
*/
|
|
oldargs = p->p_args;
|
|
p->p_args = newargs;
|
|
newargs = NULL;
|
|
|
|
#ifdef HWPMC_HOOKS
|
|
/*
|
|
* Check if system-wide sampling is in effect or if the
|
|
* current process is using PMCs. If so, do exec() time
|
|
* processing. This processing needs to happen AFTER the
|
|
* P_INEXEC flag is cleared.
|
|
*
|
|
* The proc lock needs to be released before taking the PMC
|
|
* SX.
|
|
*/
|
|
if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
|
|
PROC_UNLOCK(p);
|
|
VOP_UNLOCK(imgp->vp, 0);
|
|
pe.pm_credentialschanged = credential_changing;
|
|
pe.pm_entryaddr = imgp->entry_addr;
|
|
|
|
PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
|
|
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
|
|
} else
|
|
PROC_UNLOCK(p);
|
|
#else /* !HWPMC_HOOKS */
|
|
PROC_UNLOCK(p);
|
|
#endif
|
|
|
|
/* Set values passed into the program in registers. */
|
|
if (p->p_sysent->sv_setregs)
|
|
(*p->p_sysent->sv_setregs)(td, imgp,
|
|
(u_long)(uintptr_t)stack_base);
|
|
else
|
|
exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base);
|
|
|
|
vfs_mark_atime(imgp->vp, td->td_ucred);
|
|
|
|
SDT_PROBE(proc, kernel, , exec__success, args->fname, 0, 0, 0, 0);
|
|
|
|
VOP_UNLOCK(imgp->vp, 0);
|
|
done1:
|
|
/*
|
|
* Free any resources malloc'd earlier that we didn't use.
|
|
*/
|
|
if (euip != NULL)
|
|
uifree(euip);
|
|
if (newcred != NULL)
|
|
crfree(oldcred);
|
|
|
|
/*
|
|
* Handle deferred decrement of ref counts.
|
|
*/
|
|
if (oldtextvp != NULL)
|
|
vrele(oldtextvp);
|
|
#ifdef KTRACE
|
|
if (tracevp != NULL)
|
|
vrele(tracevp);
|
|
if (tracecred != NULL)
|
|
crfree(tracecred);
|
|
#endif
|
|
vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
|
|
pargs_drop(oldargs);
|
|
pargs_drop(newargs);
|
|
if (oldsigacts != NULL)
|
|
sigacts_free(oldsigacts);
|
|
|
|
exec_fail_dealloc:
|
|
|
|
/*
|
|
* free various allocated resources
|
|
*/
|
|
if (imgp->firstpage != NULL)
|
|
exec_unmap_first_page(imgp);
|
|
|
|
if (imgp->vp != NULL) {
|
|
if (args->fname)
|
|
NDFREE(&nd, NDF_ONLY_PNBUF);
|
|
if (imgp->opened)
|
|
VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
|
|
if (error != 0)
|
|
vput(imgp->vp);
|
|
else
|
|
VOP_UNLOCK(imgp->vp, 0);
|
|
}
|
|
|
|
if (imgp->object != NULL)
|
|
vm_object_deallocate(imgp->object);
|
|
|
|
free(imgp->freepath, M_TEMP);
|
|
|
|
if (error == 0) {
|
|
PROC_LOCK(p);
|
|
td->td_dbgflags |= TDB_EXEC;
|
|
PROC_UNLOCK(p);
|
|
|
|
/*
|
|
* Stop the process here if its stop event mask has
|
|
* the S_EXEC bit set.
|
|
*/
|
|
STOPEVENT(p, S_EXEC, 0);
|
|
goto done2;
|
|
}
|
|
|
|
exec_fail:
|
|
/* we're done here, clear P_INEXEC */
|
|
PROC_LOCK(p);
|
|
p->p_flag &= ~P_INEXEC;
|
|
PROC_UNLOCK(p);
|
|
|
|
SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0);
|
|
|
|
done2:
|
|
#ifdef MAC
|
|
mac_execve_exit(imgp);
|
|
mac_execve_interpreter_exit(interpvplabel);
|
|
#endif
|
|
exec_free_args(args);
|
|
|
|
if (error && imgp->vmspace_destroyed) {
|
|
/* sorry, no more process anymore. exit gracefully */
|
|
exit1(td, 0, SIGABRT);
|
|
/* NOT REACHED */
|
|
}
|
|
|
|
#ifdef KTRACE
|
|
if (error == 0)
|
|
ktrprocctor(p);
|
|
#endif
|
|
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
exec_map_first_page(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
int rv, i;
|
|
int initial_pagein;
|
|
vm_page_t ma[VM_INITIAL_PAGEIN];
|
|
vm_object_t object;
|
|
|
|
if (imgp->firstpage != NULL)
|
|
exec_unmap_first_page(imgp);
|
|
|
|
object = imgp->vp->v_object;
|
|
if (object == NULL)
|
|
return (EACCES);
|
|
VM_OBJECT_WLOCK(object);
|
|
#if VM_NRESERVLEVEL > 0
|
|
vm_object_color(object, 0);
|
|
#endif
|
|
ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL);
|
|
if (ma[0]->valid != VM_PAGE_BITS_ALL) {
|
|
initial_pagein = VM_INITIAL_PAGEIN;
|
|
if (initial_pagein > object->size)
|
|
initial_pagein = object->size;
|
|
for (i = 1; i < initial_pagein; i++) {
|
|
if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
|
|
if (ma[i]->valid)
|
|
break;
|
|
if (vm_page_tryxbusy(ma[i]))
|
|
break;
|
|
} else {
|
|
ma[i] = vm_page_alloc(object, i,
|
|
VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
|
|
if (ma[i] == NULL)
|
|
break;
|
|
}
|
|
}
|
|
initial_pagein = i;
|
|
rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
|
|
if (rv != VM_PAGER_OK) {
|
|
vm_page_lock(ma[0]);
|
|
vm_page_free(ma[0]);
|
|
vm_page_unlock(ma[0]);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
return (EIO);
|
|
}
|
|
}
|
|
vm_page_xunbusy(ma[0]);
|
|
vm_page_lock(ma[0]);
|
|
vm_page_hold(ma[0]);
|
|
vm_page_activate(ma[0]);
|
|
vm_page_unlock(ma[0]);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
|
|
imgp->firstpage = sf_buf_alloc(ma[0], 0);
|
|
imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
exec_unmap_first_page(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
vm_page_t m;
|
|
|
|
if (imgp->firstpage != NULL) {
|
|
m = sf_buf_page(imgp->firstpage);
|
|
sf_buf_free(imgp->firstpage);
|
|
imgp->firstpage = NULL;
|
|
vm_page_lock(m);
|
|
vm_page_unhold(m);
|
|
vm_page_unlock(m);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Destroy old address space, and allocate a new stack
|
|
* The new stack is only SGROWSIZ large because it is grown
|
|
* automatically in trap.c.
|
|
*/
|
|
int
|
|
exec_new_vmspace(imgp, sv)
|
|
struct image_params *imgp;
|
|
struct sysentvec *sv;
|
|
{
|
|
int error;
|
|
struct proc *p = imgp->proc;
|
|
struct vmspace *vmspace = p->p_vmspace;
|
|
vm_object_t obj;
|
|
struct rlimit rlim_stack;
|
|
vm_offset_t sv_minuser, stack_addr;
|
|
vm_map_t map;
|
|
u_long ssiz;
|
|
|
|
imgp->vmspace_destroyed = 1;
|
|
imgp->sysent = sv;
|
|
|
|
/* May be called with Giant held */
|
|
EVENTHANDLER_INVOKE(process_exec, p, imgp);
|
|
|
|
/*
|
|
* Blow away entire process VM, if address space not shared,
|
|
* otherwise, create a new VM space so that other threads are
|
|
* not disrupted
|
|
*/
|
|
map = &vmspace->vm_map;
|
|
if (map_at_zero)
|
|
sv_minuser = sv->sv_minuser;
|
|
else
|
|
sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
|
|
if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
|
|
vm_map_max(map) == sv->sv_maxuser) {
|
|
shmexit(vmspace);
|
|
pmap_remove_pages(vmspace_pmap(vmspace));
|
|
vm_map_remove(map, vm_map_min(map), vm_map_max(map));
|
|
} else {
|
|
error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
|
|
if (error)
|
|
return (error);
|
|
vmspace = p->p_vmspace;
|
|
map = &vmspace->vm_map;
|
|
}
|
|
|
|
/* Map a shared page */
|
|
obj = sv->sv_shared_page_obj;
|
|
if (obj != NULL) {
|
|
vm_object_reference(obj);
|
|
error = vm_map_fixed(map, obj, 0,
|
|
sv->sv_shared_page_base, sv->sv_shared_page_len,
|
|
VM_PROT_READ | VM_PROT_EXECUTE,
|
|
VM_PROT_READ | VM_PROT_EXECUTE,
|
|
MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
|
|
if (error) {
|
|
vm_object_deallocate(obj);
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
/* Allocate a new stack */
|
|
if (imgp->stack_sz != 0) {
|
|
ssiz = trunc_page(imgp->stack_sz);
|
|
PROC_LOCK(p);
|
|
lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack);
|
|
PROC_UNLOCK(p);
|
|
if (ssiz > rlim_stack.rlim_max)
|
|
ssiz = rlim_stack.rlim_max;
|
|
if (ssiz > rlim_stack.rlim_cur) {
|
|
rlim_stack.rlim_cur = ssiz;
|
|
kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack);
|
|
}
|
|
} else if (sv->sv_maxssiz != NULL) {
|
|
ssiz = *sv->sv_maxssiz;
|
|
} else {
|
|
ssiz = maxssiz;
|
|
}
|
|
stack_addr = sv->sv_usrstack - ssiz;
|
|
error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
|
|
obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
|
|
sv->sv_stackprot,
|
|
VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they
|
|
* are still used to enforce the stack rlimit on the process stack.
|
|
*/
|
|
vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
|
|
vmspace->vm_maxsaddr = (char *)stack_addr;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Copy out argument and environment strings from the old process address
|
|
* space into the temporary string buffer.
|
|
*/
|
|
int
|
|
exec_copyin_args(struct image_args *args, char *fname,
|
|
enum uio_seg segflg, char **argv, char **envv)
|
|
{
|
|
u_long argp, envp;
|
|
int error;
|
|
size_t length;
|
|
|
|
bzero(args, sizeof(*args));
|
|
if (argv == NULL)
|
|
return (EFAULT);
|
|
|
|
/*
|
|
* Allocate demand-paged memory for the file name, argument, and
|
|
* environment strings.
|
|
*/
|
|
error = exec_alloc_args(args);
|
|
if (error != 0)
|
|
return (error);
|
|
|
|
/*
|
|
* Copy the file name.
|
|
*/
|
|
if (fname != NULL) {
|
|
args->fname = args->buf;
|
|
error = (segflg == UIO_SYSSPACE) ?
|
|
copystr(fname, args->fname, PATH_MAX, &length) :
|
|
copyinstr(fname, args->fname, PATH_MAX, &length);
|
|
if (error != 0)
|
|
goto err_exit;
|
|
} else
|
|
length = 0;
|
|
|
|
args->begin_argv = args->buf + length;
|
|
args->endp = args->begin_argv;
|
|
args->stringspace = ARG_MAX;
|
|
|
|
/*
|
|
* extract arguments first
|
|
*/
|
|
for (;;) {
|
|
error = fueword(argv++, &argp);
|
|
if (error == -1) {
|
|
error = EFAULT;
|
|
goto err_exit;
|
|
}
|
|
if (argp == 0)
|
|
break;
|
|
error = copyinstr((void *)(uintptr_t)argp, args->endp,
|
|
args->stringspace, &length);
|
|
if (error != 0) {
|
|
if (error == ENAMETOOLONG)
|
|
error = E2BIG;
|
|
goto err_exit;
|
|
}
|
|
args->stringspace -= length;
|
|
args->endp += length;
|
|
args->argc++;
|
|
}
|
|
|
|
args->begin_envv = args->endp;
|
|
|
|
/*
|
|
* extract environment strings
|
|
*/
|
|
if (envv) {
|
|
for (;;) {
|
|
error = fueword(envv++, &envp);
|
|
if (error == -1) {
|
|
error = EFAULT;
|
|
goto err_exit;
|
|
}
|
|
if (envp == 0)
|
|
break;
|
|
error = copyinstr((void *)(uintptr_t)envp,
|
|
args->endp, args->stringspace, &length);
|
|
if (error != 0) {
|
|
if (error == ENAMETOOLONG)
|
|
error = E2BIG;
|
|
goto err_exit;
|
|
}
|
|
args->stringspace -= length;
|
|
args->endp += length;
|
|
args->envc++;
|
|
}
|
|
}
|
|
|
|
return (0);
|
|
|
|
err_exit:
|
|
exec_free_args(args);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
exec_copyin_data_fds(struct thread *td, struct image_args *args,
|
|
const void *data, size_t datalen, const int *fds, size_t fdslen)
|
|
{
|
|
struct filedesc *ofdp;
|
|
const char *p;
|
|
int *kfds;
|
|
int error;
|
|
|
|
memset(args, '\0', sizeof(*args));
|
|
ofdp = td->td_proc->p_fd;
|
|
if (datalen >= ARG_MAX || fdslen > ofdp->fd_lastfile + 1)
|
|
return (E2BIG);
|
|
error = exec_alloc_args(args);
|
|
if (error != 0)
|
|
return (error);
|
|
|
|
args->begin_argv = args->buf;
|
|
args->stringspace = ARG_MAX;
|
|
|
|
if (datalen > 0) {
|
|
/*
|
|
* Argument buffer has been provided. Copy it into the
|
|
* kernel as a single string and add a terminating null
|
|
* byte.
|
|
*/
|
|
error = copyin(data, args->begin_argv, datalen);
|
|
if (error != 0)
|
|
goto err_exit;
|
|
args->begin_argv[datalen] = '\0';
|
|
args->endp = args->begin_argv + datalen + 1;
|
|
args->stringspace -= datalen + 1;
|
|
|
|
/*
|
|
* Traditional argument counting. Count the number of
|
|
* null bytes.
|
|
*/
|
|
for (p = args->begin_argv; p < args->endp; ++p)
|
|
if (*p == '\0')
|
|
++args->argc;
|
|
} else {
|
|
/* No argument buffer provided. */
|
|
args->endp = args->begin_argv;
|
|
}
|
|
/* There are no environment variables. */
|
|
args->begin_envv = args->endp;
|
|
|
|
/* Create new file descriptor table. */
|
|
kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK);
|
|
error = copyin(fds, kfds, fdslen * sizeof(int));
|
|
if (error != 0) {
|
|
free(kfds, M_TEMP);
|
|
goto err_exit;
|
|
}
|
|
error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp);
|
|
free(kfds, M_TEMP);
|
|
if (error != 0)
|
|
goto err_exit;
|
|
|
|
return (0);
|
|
err_exit:
|
|
exec_free_args(args);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Allocate temporary demand-paged, zero-filled memory for the file name,
|
|
* argument, and environment strings. Returns zero if the allocation succeeds
|
|
* and ENOMEM otherwise.
|
|
*/
|
|
int
|
|
exec_alloc_args(struct image_args *args)
|
|
{
|
|
|
|
args->buf = (char *)kmap_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
|
|
return (args->buf != NULL ? 0 : ENOMEM);
|
|
}
|
|
|
|
void
|
|
exec_free_args(struct image_args *args)
|
|
{
|
|
|
|
if (args->buf != NULL) {
|
|
kmap_free_wakeup(exec_map, (vm_offset_t)args->buf,
|
|
PATH_MAX + ARG_MAX);
|
|
args->buf = NULL;
|
|
}
|
|
if (args->fname_buf != NULL) {
|
|
free(args->fname_buf, M_TEMP);
|
|
args->fname_buf = NULL;
|
|
}
|
|
if (args->fdp != NULL)
|
|
fdescfree_remapped(args->fdp);
|
|
}
|
|
|
|
/*
|
|
* Copy strings out to the new process address space, constructing new arg
|
|
* and env vector tables. Return a pointer to the base so that it can be used
|
|
* as the initial stack pointer.
|
|
*/
|
|
register_t *
|
|
exec_copyout_strings(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
int argc, envc;
|
|
char **vectp;
|
|
char *stringp;
|
|
uintptr_t destp;
|
|
register_t *stack_base;
|
|
struct ps_strings *arginfo;
|
|
struct proc *p;
|
|
size_t execpath_len;
|
|
int szsigcode, szps;
|
|
char canary[sizeof(long) * 8];
|
|
|
|
szps = sizeof(pagesizes[0]) * MAXPAGESIZES;
|
|
/*
|
|
* Calculate string base and vector table pointers.
|
|
* Also deal with signal trampoline code for this exec type.
|
|
*/
|
|
if (imgp->execpath != NULL && imgp->auxargs != NULL)
|
|
execpath_len = strlen(imgp->execpath) + 1;
|
|
else
|
|
execpath_len = 0;
|
|
p = imgp->proc;
|
|
szsigcode = 0;
|
|
arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
|
|
if (p->p_sysent->sv_sigcode_base == 0) {
|
|
if (p->p_sysent->sv_szsigcode != NULL)
|
|
szsigcode = *(p->p_sysent->sv_szsigcode);
|
|
}
|
|
destp = (uintptr_t)arginfo;
|
|
|
|
/*
|
|
* install sigcode
|
|
*/
|
|
if (szsigcode != 0) {
|
|
destp -= szsigcode;
|
|
destp = rounddown2(destp, sizeof(void *));
|
|
copyout(p->p_sysent->sv_sigcode, (void *)destp, szsigcode);
|
|
}
|
|
|
|
/*
|
|
* Copy the image path for the rtld.
|
|
*/
|
|
if (execpath_len != 0) {
|
|
destp -= execpath_len;
|
|
imgp->execpathp = destp;
|
|
copyout(imgp->execpath, (void *)destp, execpath_len);
|
|
}
|
|
|
|
/*
|
|
* Prepare the canary for SSP.
|
|
*/
|
|
arc4rand(canary, sizeof(canary), 0);
|
|
destp -= sizeof(canary);
|
|
imgp->canary = destp;
|
|
copyout(canary, (void *)destp, sizeof(canary));
|
|
imgp->canarylen = sizeof(canary);
|
|
|
|
/*
|
|
* Prepare the pagesizes array.
|
|
*/
|
|
destp -= szps;
|
|
destp = rounddown2(destp, sizeof(void *));
|
|
imgp->pagesizes = destp;
|
|
copyout(pagesizes, (void *)destp, szps);
|
|
imgp->pagesizeslen = szps;
|
|
|
|
destp -= ARG_MAX - imgp->args->stringspace;
|
|
destp = rounddown2(destp, sizeof(void *));
|
|
|
|
/*
|
|
* If we have a valid auxargs ptr, prepare some room
|
|
* on the stack.
|
|
*/
|
|
if (imgp->auxargs) {
|
|
/*
|
|
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
|
|
* lower compatibility.
|
|
*/
|
|
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
|
|
(AT_COUNT * 2);
|
|
/*
|
|
* The '+ 2' is for the null pointers at the end of each of
|
|
* the arg and env vector sets,and imgp->auxarg_size is room
|
|
* for argument of Runtime loader.
|
|
*/
|
|
vectp = (char **)(destp - (imgp->args->argc +
|
|
imgp->args->envc + 2 + imgp->auxarg_size)
|
|
* sizeof(char *));
|
|
} else {
|
|
/*
|
|
* The '+ 2' is for the null pointers at the end of each of
|
|
* the arg and env vector sets
|
|
*/
|
|
vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc
|
|
+ 2) * sizeof(char *));
|
|
}
|
|
|
|
/*
|
|
* vectp also becomes our initial stack base
|
|
*/
|
|
stack_base = (register_t *)vectp;
|
|
|
|
stringp = imgp->args->begin_argv;
|
|
argc = imgp->args->argc;
|
|
envc = imgp->args->envc;
|
|
|
|
/*
|
|
* Copy out strings - arguments and environment.
|
|
*/
|
|
copyout(stringp, (void *)destp, ARG_MAX - imgp->args->stringspace);
|
|
|
|
/*
|
|
* Fill in "ps_strings" struct for ps, w, etc.
|
|
*/
|
|
suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
|
|
suword32(&arginfo->ps_nargvstr, argc);
|
|
|
|
/*
|
|
* Fill in argument portion of vector table.
|
|
*/
|
|
for (; argc > 0; --argc) {
|
|
suword(vectp++, (long)(intptr_t)destp);
|
|
while (*stringp++ != 0)
|
|
destp++;
|
|
destp++;
|
|
}
|
|
|
|
/* a null vector table pointer separates the argp's from the envp's */
|
|
suword(vectp++, 0);
|
|
|
|
suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
|
|
suword32(&arginfo->ps_nenvstr, envc);
|
|
|
|
/*
|
|
* Fill in environment portion of vector table.
|
|
*/
|
|
for (; envc > 0; --envc) {
|
|
suword(vectp++, (long)(intptr_t)destp);
|
|
while (*stringp++ != 0)
|
|
destp++;
|
|
destp++;
|
|
}
|
|
|
|
/* end of vector table is a null pointer */
|
|
suword(vectp, 0);
|
|
|
|
return (stack_base);
|
|
}
|
|
|
|
/*
|
|
* Check permissions of file to execute.
|
|
* Called with imgp->vp locked.
|
|
* Return 0 for success or error code on failure.
|
|
*/
|
|
int
|
|
exec_check_permissions(imgp)
|
|
struct image_params *imgp;
|
|
{
|
|
struct vnode *vp = imgp->vp;
|
|
struct vattr *attr = imgp->attr;
|
|
struct thread *td;
|
|
int error, writecount;
|
|
|
|
td = curthread;
|
|
|
|
/* Get file attributes */
|
|
error = VOP_GETATTR(vp, attr, td->td_ucred);
|
|
if (error)
|
|
return (error);
|
|
|
|
#ifdef MAC
|
|
error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
|
|
/*
|
|
* 1) Check if file execution is disabled for the filesystem that
|
|
* this file resides on.
|
|
* 2) Ensure that at least one execute bit is on. Otherwise, a
|
|
* privileged user will always succeed, and we don't want this
|
|
* to happen unless the file really is executable.
|
|
* 3) Ensure that the file is a regular file.
|
|
*/
|
|
if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
|
|
(attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
|
|
(attr->va_type != VREG))
|
|
return (EACCES);
|
|
|
|
/*
|
|
* Zero length files can't be exec'd
|
|
*/
|
|
if (attr->va_size == 0)
|
|
return (ENOEXEC);
|
|
|
|
/*
|
|
* Check for execute permission to file based on current credentials.
|
|
*/
|
|
error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* Check number of open-for-writes on the file and deny execution
|
|
* if there are any.
|
|
*/
|
|
error = VOP_GET_WRITECOUNT(vp, &writecount);
|
|
if (error != 0)
|
|
return (error);
|
|
if (writecount != 0)
|
|
return (ETXTBSY);
|
|
|
|
/*
|
|
* Call filesystem specific open routine (which does nothing in the
|
|
* general case).
|
|
*/
|
|
error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
|
|
if (error == 0)
|
|
imgp->opened = 1;
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Exec handler registration
|
|
*/
|
|
int
|
|
exec_register(execsw_arg)
|
|
const struct execsw *execsw_arg;
|
|
{
|
|
const struct execsw **es, **xs, **newexecsw;
|
|
int count = 2; /* New slot and trailing NULL */
|
|
|
|
if (execsw)
|
|
for (es = execsw; *es; es++)
|
|
count++;
|
|
newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
|
|
if (newexecsw == NULL)
|
|
return (ENOMEM);
|
|
xs = newexecsw;
|
|
if (execsw)
|
|
for (es = execsw; *es; es++)
|
|
*xs++ = *es;
|
|
*xs++ = execsw_arg;
|
|
*xs = NULL;
|
|
if (execsw)
|
|
free(execsw, M_TEMP);
|
|
execsw = newexecsw;
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
exec_unregister(execsw_arg)
|
|
const struct execsw *execsw_arg;
|
|
{
|
|
const struct execsw **es, **xs, **newexecsw;
|
|
int count = 1;
|
|
|
|
if (execsw == NULL)
|
|
panic("unregister with no handlers left?\n");
|
|
|
|
for (es = execsw; *es; es++) {
|
|
if (*es == execsw_arg)
|
|
break;
|
|
}
|
|
if (*es == NULL)
|
|
return (ENOENT);
|
|
for (es = execsw; *es; es++)
|
|
if (*es != execsw_arg)
|
|
count++;
|
|
newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
|
|
if (newexecsw == NULL)
|
|
return (ENOMEM);
|
|
xs = newexecsw;
|
|
for (es = execsw; *es; es++)
|
|
if (*es != execsw_arg)
|
|
*xs++ = *es;
|
|
*xs = NULL;
|
|
if (execsw)
|
|
free(execsw, M_TEMP);
|
|
execsw = newexecsw;
|
|
return (0);
|
|
}
|