2 * SPDX-License-Identifier: BSD-4-Clause
4 * Copyright (C) 1994, David Greenman
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 * Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
9 * This code is derived from software contributed to Berkeley by
10 * the University of Utah, and William Jolitz.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
43 #include "opt_capsicum.h"
44 #include "opt_ktrace.h"
46 __FBSDID("$FreeBSD$");
48 #include <sys/capsicum.h>
50 #include <sys/vmmeter.h>
53 #include <sys/ktrace.h>
55 #include <security/audit/audit.h>
58 syscallenter(struct thread *td)
61 struct syscall_args *sa;
64 VM_CNT_INC(v_syscall);
69 if (__predict_false(td->td_cowgen != p->p_cowgen))
70 thread_cow_update(td);
71 traced = (p->p_flag & P_TRACED) != 0;
72 if (__predict_false(traced || td->td_dbgflags & TDB_USERWR)) {
74 td->td_dbgflags &= ~TDB_USERWR;
76 td->td_dbgflags |= TDB_SCE;
79 error = (p->p_sysent->sv_fetch_syscall_args)(td);
81 if (KTRPOINT(td, KTR_SYSCALL))
82 ktrsyscall(sa->code, sa->callp->sy_narg, sa->args);
84 KTR_START4(KTR_SYSC, "syscall", syscallname(p, sa->code),
85 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
86 "arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
88 if (__predict_false(error != 0)) {
93 if (__predict_false(traced)) {
95 if (p->p_ptevents & PTRACE_SCE)
96 ptracestop((td), SIGTRAP, NULL);
99 if (__predict_false((td->td_dbgflags & TDB_USERWR) != 0)) {
101 * Reread syscall number and arguments if debugger
102 * modified registers or memory.
104 error = (p->p_sysent->sv_fetch_syscall_args)(td);
106 if (KTRPOINT(td, KTR_SYSCALL))
107 ktrsyscall(sa->code, sa->callp->sy_narg, sa->args);
110 td->td_errno = error;
115 #ifdef CAPABILITY_MODE
117 * In capability mode, we only allow access to system calls
118 * flagged with SYF_CAPENABLED.
120 if (__predict_false(IN_CAPABILITY_MODE(td) &&
121 !(sa->callp->sy_flags & SYF_CAPENABLED))) {
122 td->td_errno = error = ECAPMODE;
127 error = syscall_thread_enter(td, sa->callp);
129 td->td_errno = error;
134 * Fetch fast sigblock value at the time of syscall entry to
135 * handle sleepqueue primitives which might call cursig().
137 if (__predict_false(sigfastblock_fetch_always))
138 (void)sigfastblock_fetch(td);
140 /* Let system calls set td_errno directly. */
141 KASSERT((td->td_pflags & TDP_NERRNO) == 0,
142 ("%s: TDP_NERRNO set", __func__));
144 if (__predict_false(SYSTRACE_ENABLED() ||
145 AUDIT_SYSCALL_ENTER(sa->code, td))) {
147 /* Give the syscall:::entry DTrace probe a chance to fire. */
148 if (__predict_false(sa->callp->sy_entry != 0))
149 (*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0);
151 error = (sa->callp->sy_call)(td, sa->args);
152 /* Save the latest error return value. */
153 if (__predict_false((td->td_pflags & TDP_NERRNO) != 0))
154 td->td_pflags &= ~TDP_NERRNO;
156 td->td_errno = error;
157 AUDIT_SYSCALL_EXIT(error, td);
159 /* Give the syscall:::return DTrace probe a chance to fire. */
160 if (__predict_false(sa->callp->sy_return != 0))
161 (*systrace_probe_func)(sa, SYSTRACE_RETURN,
162 error ? -1 : td->td_retval[0]);
165 error = (sa->callp->sy_call)(td, sa->args);
166 /* Save the latest error return value. */
167 if (__predict_false((td->td_pflags & TDP_NERRNO) != 0))
168 td->td_pflags &= ~TDP_NERRNO;
170 td->td_errno = error;
172 syscall_thread_exit(td, sa->callp);
175 KTR_STOP4(KTR_SYSC, "syscall", syscallname(p, sa->code),
176 (uintptr_t)td, "pid:%d", td->td_proc->p_pid, "error:%d", error,
177 "retval0:%#lx", td->td_retval[0], "retval1:%#lx",
179 if (__predict_false(traced)) {
181 td->td_dbgflags &= ~TDB_SCE;
184 (p->p_sysent->sv_set_syscall_retval)(td, error);
188 syscallret(struct thread *td)
191 struct syscall_args *sa;
195 KASSERT((td->td_pflags & TDP_FORKING) == 0,
196 ("fork() did not clear TDP_FORKING upon completion"));
200 if (__predict_false(td->td_errno == ENOTCAPABLE ||
201 td->td_errno == ECAPMODE)) {
203 (p->p_flag2 & P2_TRAPCAP) != 0) && IN_CAPABILITY_MODE(td)) {
204 ksiginfo_init_trap(&ksi);
205 ksi.ksi_signo = SIGTRAP;
206 ksi.ksi_errno = td->td_errno;
207 ksi.ksi_code = TRAP_CAP;
208 trapsignal(td, &ksi);
213 * Handle reschedule and other end-of-syscall issues
215 userret(td, td->td_frame);
218 if (KTRPOINT(td, KTR_SYSRET)) {
219 ktrsysret(sa->code, td->td_errno, td->td_retval[0]);
224 if (__predict_false(p->p_flag & P_TRACED)) {
227 td->td_dbgflags |= TDB_SCX;
230 if (__predict_false(traced ||
231 (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0)) {
234 * If tracing the execed process, trap to the debugger
235 * so that breakpoints can be set before the program
236 * executes. If debugger requested tracing of syscall
237 * returns, do it now too.
240 ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 ||
241 (p->p_ptevents & PTRACE_SCX) != 0))
242 ptracestop(td, SIGTRAP, NULL);
243 td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
247 if (__predict_false(td->td_pflags & TDP_RFPPWAIT))