1 /* $OpenBSD: syscall_mi.h,v 1.34 2024/06/02 15:31:57 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)kern_xxx.c 8.2 (Berkeley) 11/14/93
32 */
33
34 #include <sys/param.h>
35 #include <sys/pledge.h>
36 #include <sys/acct.h>
37 #include <sys/syslog.h>
38 #include <sys/tracepoint.h>
39 #include <sys/syscall.h>
40 #include <sys/signalvar.h>
41 #include <uvm/uvm_extern.h>
42
43 #ifdef KTRACE
44 #include <sys/ktrace.h>
45 #endif
46
47 #include "dt.h"
48 #if NDT > 0
49 #include <dev/dt/dtvar.h>
50 #endif
51
52 /*
53 * Check if a system call is entered from precisely correct location
54 */
55 static inline int
pin_check(struct proc * p,register_t code)56 pin_check(struct proc *p, register_t code)
57 {
58 extern char sigcodecall[], sigcoderet[], sigcodecall[];
59 struct pinsyscall *pin = NULL, *ppin, *plibcpin;
60 struct process *pr = p->p_p;
61 vaddr_t addr;
62 int error = 0;
63
64 /* point at start of syscall instruction */
65 addr = (vaddr_t)PROC_PC(p) - (vaddr_t)(sigcoderet - sigcodecall);
66 ppin = &pr->ps_pin;
67 plibcpin = &pr->ps_libcpin;
68
69 /*
70 * System calls come from the following places, checks are ordered
71 * by most common case:
72 * 1) dynamic binary: syscalls in libc.so (in the ps_libcpin region)
73 * 2a) static binary: syscalls in main program (in the ps_pin region)
74 * 2b) dynamic binary: sysalls in ld.so (in the ps_pin region)
75 * 3) sigtramp, containing only sigreturn(2)
76 */
77 if (plibcpin->pn_pins &&
78 addr >= plibcpin->pn_start && addr < plibcpin->pn_end)
79 pin = plibcpin;
80 else if (ppin->pn_pins &&
81 addr >= ppin->pn_start && addr < ppin->pn_end)
82 pin = ppin;
83 else if (PROC_PC(p) == pr->ps_sigcoderet) {
84 if (code == SYS_sigreturn)
85 return (0);
86 error = EPERM;
87 goto die;
88 }
89 if (pin) {
90 if (code >= pin->pn_npins || pin->pn_pins[code] == 0)
91 error = ENOSYS;
92 else if (pin->pn_pins[code] + pin->pn_start == addr)
93 ; /* correct location */
94 else if (pin->pn_pins[code] == (u_int)-1)
95 ; /* multiple locations, hopefully a boring operation */
96 else
97 error = ENOSYS;
98 } else
99 error = ENOSYS;
100 if (error == 0)
101 return (0);
102 die:
103 #ifdef KTRACE
104 if (KTRPOINT(p, KTR_PINSYSCALL))
105 ktrpinsyscall(p, error, code, addr);
106 #endif
107 KERNEL_LOCK();
108 /* XXX remove or simplify this uprintf() call after OpenBSD 7.5 release */
109 uprintf("%s[%d]: pinsyscalls addr %lx code %ld, pinoff 0x%x "
110 "(pin%s %d %lx-%lx %lx) (libcpin%s %d %lx-%lx %lx) error %d\n",
111 p->p_p->ps_comm, p->p_p->ps_pid, addr, code,
112 (pin && code < pin->pn_npins) ? pin->pn_pins[code] : -1,
113 pin == ppin ? "(Y)" : "", ppin->pn_npins,
114 ppin->pn_start, ppin->pn_end, ppin->pn_end - ppin->pn_start,
115 pin == plibcpin ? "(Y)" : "", plibcpin->pn_npins,
116 plibcpin->pn_start, plibcpin->pn_end, plibcpin->pn_end - plibcpin->pn_start,
117 error);
118 p->p_p->ps_acflag |= APINSYS;
119
120 /* Try to stop threads immediately, because this process is suspect */
121 if (P_HASSIBLING(p))
122 single_thread_set(p, SINGLE_UNWIND | SINGLE_DEEP);
123 /* Send uncatchable SIGABRT for coredump */
124 sigabort(p);
125 KERNEL_UNLOCK();
126 return (error);
127 }
128
129 /*
130 * The MD setup for a system call has been done; here's the MI part.
131 */
132 static inline int
mi_syscall(struct proc * p,register_t code,const struct sysent * callp,register_t * argp,register_t retval[2])133 mi_syscall(struct proc *p, register_t code, const struct sysent *callp,
134 register_t *argp, register_t retval[2])
135 {
136 uint64_t tval;
137 int lock = !(callp->sy_flags & SY_NOLOCK);
138 int error, pledged;
139
140 /* refresh the thread's cache of the process's creds */
141 refreshcreds(p);
142
143 #ifdef SYSCALL_DEBUG
144 KERNEL_LOCK();
145 scdebug_call(p, code, argp);
146 KERNEL_UNLOCK();
147 #endif
148 TRACEPOINT(raw_syscalls, sys_enter, code, NULL);
149 #if NDT > 0
150 DT_ENTER(syscall, code, callp->sy_argsize, argp);
151 #endif
152 #ifdef KTRACE
153 if (KTRPOINT(p, KTR_SYSCALL)) {
154 /* convert to mask, then include with code */
155 KERNEL_LOCK();
156 ktrsyscall(p, code, callp->sy_argsize, argp);
157 KERNEL_UNLOCK();
158 }
159 #endif
160
161 /* SP must be within MAP_STACK space */
162 if (!uvm_map_inentry(p, &p->p_spinentry, PROC_STACK(p),
163 "[%s]%d/%d sp=%lx inside %lx-%lx: not MAP_STACK\n",
164 uvm_map_inentry_sp, p->p_vmspace->vm_map.sserial))
165 return (EPERM);
166
167 if ((error = pin_check(p, code)))
168 return (error);
169
170 pledged = (p->p_p->ps_flags & PS_PLEDGE);
171 if (pledged && (error = pledge_syscall(p, code, &tval))) {
172 KERNEL_LOCK();
173 error = pledge_fail(p, error, tval);
174 KERNEL_UNLOCK();
175 return (error);
176 }
177 if (lock)
178 KERNEL_LOCK();
179 error = (*callp->sy_call)(p, argp, retval);
180 if (lock)
181 KERNEL_UNLOCK();
182
183 return (error);
184 }
185
186 /*
187 * Finish MI stuff on return, after the registers have been set
188 */
189 static inline void
mi_syscall_return(struct proc * p,register_t code,int error,const register_t retval[2])190 mi_syscall_return(struct proc *p, register_t code, int error,
191 const register_t retval[2])
192 {
193 #ifdef SYSCALL_DEBUG
194 KERNEL_LOCK();
195 scdebug_ret(p, code, error, retval);
196 KERNEL_UNLOCK();
197 #endif
198 #if NDT > 0
199 DT_LEAVE(syscall, code, error, retval[0], retval[1]);
200 #endif
201 TRACEPOINT(raw_syscalls, sys_exit, code, NULL);
202
203 userret(p);
204
205 #ifdef KTRACE
206 if (KTRPOINT(p, KTR_SYSRET)) {
207 KERNEL_LOCK();
208 ktrsysret(p, code, error, retval);
209 KERNEL_UNLOCK();
210 }
211 #endif
212 }
213
214 /*
215 * Finish MI stuff for a new process/thread to return
216 */
217 static inline void
mi_child_return(struct proc * p)218 mi_child_return(struct proc *p)
219 {
220 #if defined(SYSCALL_DEBUG) || defined(KTRACE) || NDT > 0
221 int code = (p->p_flag & P_THREAD) ? SYS___tfork :
222 (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork;
223 const register_t child_retval[2] = { 0, 1 };
224 #endif
225
226 TRACEPOINT(sched, on__cpu, NULL);
227
228 #ifdef SYSCALL_DEBUG
229 KERNEL_LOCK();
230 scdebug_ret(p, code, 0, child_retval);
231 KERNEL_UNLOCK();
232 #endif
233 #if NDT > 0
234 DT_LEAVE(syscall, code, 0, child_retval[0], child_retval[1]);
235 #endif
236 TRACEPOINT(raw_syscalls, sys_exit, code, NULL);
237
238 userret(p);
239
240 #ifdef KTRACE
241 if (KTRPOINT(p, KTR_SYSRET)) {
242 KERNEL_LOCK();
243 ktrsysret(p, code, 0, child_retval);
244 KERNEL_UNLOCK();
245 }
246 #endif
247 }
248
249 /*
250 * Do the specific processing necessary for an AST
251 */
252 static inline void
mi_ast(struct proc * p,int resched)253 mi_ast(struct proc *p, int resched)
254 {
255 if (p->p_flag & P_OWEUPC) {
256 KERNEL_LOCK();
257 ADDUPROF(p);
258 KERNEL_UNLOCK();
259 }
260 if (resched)
261 preempt();
262
263 /*
264 * XXX could move call to userret() here, but
265 * hppa calls ast() in syscall return and sh calls
266 * it after userret()
267 */
268 }
269