/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
*/
#include "opt_capsicum.h"
#include "opt_ktrace.h"
__FBSDID("$FreeBSD$");
#include <sys/capsicum.h>
#include <sys/ktr.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#include <security/audit/audit.h>
static inline void
syscallenter(struct thread *td)
{
struct proc *p;
struct syscall_args *sa;
int error, traced;
VM_CNT_INC(v_syscall);
p = td->td_proc;
sa = &td->td_sa;
td->td_pticks = 0;
if (__predict_false(td->td_cowgen != p->p_cowgen))
thread_cow_update(td);
traced = (p->p_flag & P_TRACED) != 0;
if (__predict_false(traced || td->td_dbgflags & TDB_USERWR)) {
PROC_LOCK(p);
td->td_dbgflags &= ~TDB_USERWR;
if (traced)
td->td_dbgflags |= TDB_SCE;
PROC_UNLOCK(p);
}
error = (p->p_sysent->sv_fetch_syscall_args)(td);
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSCALL))
ktrsyscall(sa->code, sa->narg, sa->args);
#endif
KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
(uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
"arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
if (__predict_false(error != 0)) {
td->td_errno = error;
goto retval;
}
if (__predict_false((p->p_flag & P_TRACED) != 0)) {
PROC_LOCK(p);
if (p->p_ptevents & PTRACE_SCE)
ptracestop((td), SIGTRAP, NULL);
PROC_UNLOCK(p);
}
if (__predict_false((td->td_dbgflags & TDB_USERWR) != 0)) {
/*
* Reread syscall number and arguments if debugger
* modified registers or memory.
*/
error = (p->p_sysent->sv_fetch_syscall_args)(td);
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSCALL))
ktrsyscall(sa->code, sa->narg, sa->args);
#endif
if (error != 0) {
td->td_errno = error;
goto retval;
}
}
#ifdef CAPABILITY_MODE
/*
* In capability mode, we only allow access to system calls
* flagged with SYF_CAPENABLED.
*/
if (__predict_false(IN_CAPABILITY_MODE(td) &&
!(sa->callp->sy_flags & SYF_CAPENABLED))) {
td->td_errno = error = ECAPMODE;
goto retval;
}
#endif
error = syscall_thread_enter(td, sa->callp);
if (error != 0) {
td->td_errno = error;
goto retval;
}
/*
* Fetch fast sigblock value at the time of syscall entry to
* handle sleepqueue primitives which might call cursig().
*/
if (__predict_false(sigfastblock_fetch_always))
(void)sigfastblock_fetch(td);
/* Let system calls set td_errno directly. */
td->td_pflags &= ~TDP_NERRNO;
if (__predict_false(SYSTRACE_ENABLED() ||
AUDIT_SYSCALL_ENTER(sa->code, td))) {
#ifdef KDTRACE_HOOKS
/* Give the syscall:::entry DTrace probe a chance to fire. */
if (__predict_false(sa->callp->sy_entry != 0))
(*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0);
#endif
error = (sa->callp->sy_call)(td, sa->args);
/* Save the latest error return value. */
if (__predict_false((td->td_pflags & TDP_NERRNO) == 0))
td->td_errno = error;
AUDIT_SYSCALL_EXIT(error, td);
#ifdef KDTRACE_HOOKS
/* Give the syscall:::return DTrace probe a chance to fire. */
if (__predict_false(sa->callp->sy_return != 0))
(*systrace_probe_func)(sa, SYSTRACE_RETURN,
error ? -1 : td->td_retval[0]);
#endif
} else {
error = (sa->callp->sy_call)(td, sa->args);
/* Save the latest error return value. */
if (__predict_false((td->td_pflags & TDP_NERRNO) == 0))
td->td_errno = error;
}
syscall_thread_exit(td, sa->callp);
retval:
KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),
(uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error,
"retval0:%#lx", td->td_retval[0], "retval1:%#lx",
td->td_retval[1]);
if (__predict_false(traced)) {
PROC_LOCK(p);
td->td_dbgflags &= ~TDB_SCE;
PROC_UNLOCK(p);
}
(p->p_sysent->sv_set_syscall_retval)(td, error);
}
static inline void
syscallret(struct thread *td)
{
struct proc *p;
struct syscall_args *sa;
ksiginfo_t ksi;
int traced;
KASSERT((td->td_pflags & TDP_FORKING) == 0,
("fork() did not clear TDP_FORKING upon completion"));
p = td->td_proc;
sa = &td->td_sa;
if (__predict_false(td->td_errno == ENOTCAPABLE ||
td->td_errno == ECAPMODE)) {
if ((trap_enotcap ||
(p->p_flag2 & P2_TRAPCAP) != 0) && IN_CAPABILITY_MODE(td)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGTRAP;
ksi.ksi_errno = td->td_errno;
ksi.ksi_code = TRAP_CAP;
trapsignal(td, &ksi);
}
}
/*
* Handle reschedule and other end-of-syscall issues
*/
userret(td, td->td_frame);
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSRET)) {
ktrsysret(sa->code, td->td_errno, td->td_retval[0]);
}
#endif
traced = 0;
if (__predict_false(p->p_flag & P_TRACED)) {
traced = 1;
PROC_LOCK(p);
td->td_dbgflags |= TDB_SCX;
PROC_UNLOCK(p);
}
if (__predict_false(traced ||
(td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0)) {
PROC_LOCK(p);
/*
* If tracing the execed process, trap to the debugger
* so that breakpoints can be set before the program
* executes. If debugger requested tracing of syscall
* returns, do it now too.
*/
if (traced &&
((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
(p->p_ptevents & PTRACE_SCX) != 0))
ptracestop(td, SIGTRAP, NULL);
td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
PROC_UNLOCK(p);
}
if (__predict_false(td->td_pflags & TDP_RFPPWAIT))
fork_rfppwait(td);
}
