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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2021 Benjamin Berg <benjamin@sipsolutions.net>
4 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 */
6
7#include <stddef.h>
8#include <unistd.h>
9#include <errno.h>
10#include <string.h>
11#include <sys/mman.h>
12#include <init.h>
13#include <as-layout.h>
14#include <mm_id.h>
15#include <os.h>
16#include <ptrace_user.h>
17#include <registers.h>
18#include <skas.h>
19#include <sysdep/ptrace.h>
20#include <sysdep/stub.h>
21#include "../internal.h"
22
23extern char __syscall_stub_start[];
24
25void syscall_stub_dump_error(struct mm_id *mm_idp)
26{
27 struct stub_data *proc_data = (void *)mm_idp->stack;
28 struct stub_syscall *sc;
29
30 if (proc_data->syscall_data_len < 0 ||
31 proc_data->syscall_data_len >= ARRAY_SIZE(proc_data->syscall_data))
32 panic("Syscall data was corrupted by stub (len is: %d, expected maximum: %d)!",
33 proc_data->syscall_data_len,
34 mm_idp->syscall_data_len);
35
36 sc = &proc_data->syscall_data[proc_data->syscall_data_len];
37
38 printk(UM_KERN_ERR "%s : length = %d, last offset = %d",
39 __func__, mm_idp->syscall_data_len,
40 proc_data->syscall_data_len);
41 printk(UM_KERN_ERR "%s : stub syscall type %d failed, return value = 0x%lx\n",
42 __func__, sc->syscall, proc_data->err);
43
44 print_hex_dump(UM_KERN_ERR, " syscall data: ", 0,
45 16, 4, sc, sizeof(*sc), 0);
46}
47
48static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
49 unsigned long *stack)
50{
51 if (stack == NULL) {
52 stack = (unsigned long *) mm_idp->stack + 2;
53 *stack = 0;
54 }
55 return stack;
56}
57
58static unsigned long syscall_regs[MAX_REG_NR];
59
60static int __init init_syscall_regs(void)
61{
62 get_safe_registers(syscall_regs, NULL);
63
64 syscall_regs[REGS_IP_INDEX] = STUB_CODE +
65 ((unsigned long) stub_syscall_handler -
66 (unsigned long) __syscall_stub_start);
67 syscall_regs[REGS_SP_INDEX] = STUB_DATA +
68 offsetof(struct stub_data, sigstack) +
69 sizeof(((struct stub_data *) 0)->sigstack) -
70 sizeof(void *);
71
72 return 0;
73}
74
75__initcall(init_syscall_regs);
76
77static inline long do_syscall_stub(struct mm_id *mm_idp)
78{
79 struct stub_data *proc_data = (void *)mm_idp->stack;
80 int n, i;
81 int err, pid = mm_idp->pid;
82
83 n = ptrace_setregs(pid, syscall_regs);
84 if (n < 0) {
85 printk(UM_KERN_ERR "Registers - \n");
86 for (i = 0; i < MAX_REG_NR; i++)
87 printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
88 panic("%s : PTRACE_SETREGS failed, errno = %d\n",
89 __func__, -n);
90 }
91
92 /* Inform process how much we have filled in. */
93 proc_data->syscall_data_len = mm_idp->syscall_data_len;
94
95 err = ptrace(PTRACE_CONT, pid, 0, 0);
96 if (err)
97 panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
98 errno);
99
100 wait_stub_done(pid);
101
102 /*
103 * proc_data->err will be non-zero if there was an (unexpected) error.
104 * In that case, syscall_data_len points to the last executed syscall,
105 * otherwise it will be zero (but we do not need to rely on that).
106 */
107 if (proc_data->err < 0) {
108 syscall_stub_dump_error(mm_idp);
109
110 /* Store error code in case someone tries to add more syscalls */
111 mm_idp->syscall_data_len = proc_data->err;
112 } else {
113 mm_idp->syscall_data_len = 0;
114 }
115
116 return mm_idp->syscall_data_len;
117}
118
119int syscall_stub_flush(struct mm_id *mm_idp)
120{
121 int res;
122
123 if (mm_idp->syscall_data_len == 0)
124 return 0;
125
126 /* If an error happened already, report it and reset the state. */
127 if (mm_idp->syscall_data_len < 0) {
128 res = mm_idp->syscall_data_len;
129 mm_idp->syscall_data_len = 0;
130 return res;
131 }
132
133 res = do_syscall_stub(mm_idp);
134 mm_idp->syscall_data_len = 0;
135
136 return res;
137}
138
139struct stub_syscall *syscall_stub_alloc(struct mm_id *mm_idp)
140{
141 struct stub_syscall *sc;
142 struct stub_data *proc_data = (struct stub_data *) mm_idp->stack;
143
144 if (mm_idp->syscall_data_len > 0 &&
145 mm_idp->syscall_data_len == ARRAY_SIZE(proc_data->syscall_data))
146 do_syscall_stub(mm_idp);
147
148 if (mm_idp->syscall_data_len < 0) {
149 /* Return dummy to retain error state. */
150 sc = &proc_data->syscall_data[0];
151 } else {
152 sc = &proc_data->syscall_data[mm_idp->syscall_data_len];
153 mm_idp->syscall_data_len += 1;
154 }
155 memset(sc, 0, sizeof(*sc));
156
157 return sc;
158}
159
160static struct stub_syscall *syscall_stub_get_previous(struct mm_id *mm_idp,
161 int syscall_type,
162 unsigned long virt)
163{
164 if (mm_idp->syscall_data_len > 0) {
165 struct stub_data *proc_data = (void *) mm_idp->stack;
166 struct stub_syscall *sc;
167
168 sc = &proc_data->syscall_data[mm_idp->syscall_data_len - 1];
169
170 if (sc->syscall == syscall_type &&
171 sc->mem.addr + sc->mem.length == virt)
172 return sc;
173 }
174
175 return NULL;
176}
177
178int map(struct mm_id *mm_idp, unsigned long virt, unsigned long len, int prot,
179 int phys_fd, unsigned long long offset)
180{
181 struct stub_syscall *sc;
182
183 /* Compress with previous syscall if that is possible */
184 sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MMAP, virt);
185 if (sc && sc->mem.prot == prot && sc->mem.fd == phys_fd &&
186 sc->mem.offset == MMAP_OFFSET(offset - sc->mem.length)) {
187 sc->mem.length += len;
188 return 0;
189 }
190
191 sc = syscall_stub_alloc(mm_idp);
192 sc->syscall = STUB_SYSCALL_MMAP;
193 sc->mem.addr = virt;
194 sc->mem.length = len;
195 sc->mem.prot = prot;
196 sc->mem.fd = phys_fd;
197 sc->mem.offset = MMAP_OFFSET(offset);
198
199 return 0;
200}
201
202int unmap(struct mm_id *mm_idp, unsigned long addr, unsigned long len)
203{
204 struct stub_syscall *sc;
205
206 /* Compress with previous syscall if that is possible */
207 sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MUNMAP, addr);
208 if (sc) {
209 sc->mem.length += len;
210 return 0;
211 }
212
213 sc = syscall_stub_alloc(mm_idp);
214 sc->syscall = STUB_SYSCALL_MUNMAP;
215 sc->mem.addr = addr;
216 sc->mem.length = len;
217
218 return 0;
219}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <stddef.h>
7#include <unistd.h>
8#include <errno.h>
9#include <string.h>
10#include <sys/mman.h>
11#include <init.h>
12#include <as-layout.h>
13#include <mm_id.h>
14#include <os.h>
15#include <ptrace_user.h>
16#include <registers.h>
17#include <skas.h>
18#include <sysdep/ptrace.h>
19#include <sysdep/stub.h>
20
21extern char batch_syscall_stub[], __syscall_stub_start[];
22
23extern void wait_stub_done(int pid);
24
25static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
26 unsigned long *stack)
27{
28 if (stack == NULL) {
29 stack = (unsigned long *) mm_idp->stack + 2;
30 *stack = 0;
31 }
32 return stack;
33}
34
35static unsigned long syscall_regs[MAX_REG_NR];
36
37static int __init init_syscall_regs(void)
38{
39 get_safe_registers(syscall_regs, NULL);
40 syscall_regs[REGS_IP_INDEX] = STUB_CODE +
41 ((unsigned long) batch_syscall_stub -
42 (unsigned long) __syscall_stub_start);
43 syscall_regs[REGS_SP_INDEX] = STUB_DATA;
44
45 return 0;
46}
47
48__initcall(init_syscall_regs);
49
50static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
51{
52 int n, i;
53 long ret, offset;
54 unsigned long * data;
55 unsigned long * syscall;
56 int err, pid = mm_idp->u.pid;
57
58 n = ptrace_setregs(pid, syscall_regs);
59 if (n < 0) {
60 printk(UM_KERN_ERR "Registers - \n");
61 for (i = 0; i < MAX_REG_NR; i++)
62 printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
63 panic("%s : PTRACE_SETREGS failed, errno = %d\n",
64 __func__, -n);
65 }
66
67 err = ptrace(PTRACE_CONT, pid, 0, 0);
68 if (err)
69 panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
70 errno);
71
72 wait_stub_done(pid);
73
74 /*
75 * When the stub stops, we find the following values on the
76 * beginning of the stack:
77 * (long )return_value
78 * (long )offset to failed sycall-data (0, if no error)
79 */
80 ret = *((unsigned long *) mm_idp->stack);
81 offset = *((unsigned long *) mm_idp->stack + 1);
82 if (offset) {
83 data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
84 printk(UM_KERN_ERR "%s : ret = %ld, offset = %ld, data = %p\n",
85 __func__, ret, offset, data);
86 syscall = (unsigned long *)((unsigned long)data + data[0]);
87 printk(UM_KERN_ERR "%s: syscall %ld failed, return value = 0x%lx, expected return value = 0x%lx\n",
88 __func__, syscall[0], ret, syscall[7]);
89 printk(UM_KERN_ERR " syscall parameters: 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
90 syscall[1], syscall[2], syscall[3],
91 syscall[4], syscall[5], syscall[6]);
92 for (n = 1; n < data[0]/sizeof(long); n++) {
93 if (n == 1)
94 printk(UM_KERN_ERR " additional syscall data:");
95 if (n % 4 == 1)
96 printk("\n" UM_KERN_ERR " ");
97 printk(" 0x%lx", data[n]);
98 }
99 if (n > 1)
100 printk("\n");
101 }
102 else ret = 0;
103
104 *addr = check_init_stack(mm_idp, NULL);
105
106 return ret;
107}
108
109long run_syscall_stub(struct mm_id * mm_idp, int syscall,
110 unsigned long *args, long expected, void **addr,
111 int done)
112{
113 unsigned long *stack = check_init_stack(mm_idp, *addr);
114
115 *stack += sizeof(long);
116 stack += *stack / sizeof(long);
117
118 *stack++ = syscall;
119 *stack++ = args[0];
120 *stack++ = args[1];
121 *stack++ = args[2];
122 *stack++ = args[3];
123 *stack++ = args[4];
124 *stack++ = args[5];
125 *stack++ = expected;
126 *stack = 0;
127
128 if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
129 UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
130 *addr = stack;
131 return 0;
132 }
133
134 return do_syscall_stub(mm_idp, addr);
135}
136
137long syscall_stub_data(struct mm_id * mm_idp,
138 unsigned long *data, int data_count,
139 void **addr, void **stub_addr)
140{
141 unsigned long *stack;
142 int ret = 0;
143
144 /*
145 * If *addr still is uninitialized, it *must* contain NULL.
146 * Thus in this case do_syscall_stub correctly won't be called.
147 */
148 if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
149 UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
150 ret = do_syscall_stub(mm_idp, addr);
151 /* in case of error, don't overwrite data on stack */
152 if (ret)
153 return ret;
154 }
155
156 stack = check_init_stack(mm_idp, *addr);
157 *addr = stack;
158
159 *stack = data_count * sizeof(long);
160
161 memcpy(stack + 1, data, data_count * sizeof(long));
162
163 *stub_addr = (void *)(((unsigned long)(stack + 1) &
164 ~UM_KERN_PAGE_MASK) + STUB_DATA);
165
166 return 0;
167}
168
169int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot,
170 int phys_fd, unsigned long long offset, int done, void **data)
171{
172 int ret;
173 unsigned long args[] = { virt, len, prot,
174 MAP_SHARED | MAP_FIXED, phys_fd,
175 MMAP_OFFSET(offset) };
176
177 ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt,
178 data, done);
179
180 return ret;
181}
182
183int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
184 int done, void **data)
185{
186 int ret;
187 unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
188 0 };
189
190 ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0,
191 data, done);
192
193 return ret;
194}
195
196int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
197 unsigned int prot, int done, void **data)
198{
199 int ret;
200 unsigned long args[] = { addr, len, prot, 0, 0, 0 };
201
202 ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0,
203 data, done);
204
205 return ret;
206}