Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0
2 : : #include <linux/compat.h>
3 : : #include <linux/uaccess.h>
4 : : #include <linux/ptrace.h>
5 : :
6 : : /*
7 : : * The compat_siginfo_t structure and handing code is very easy
8 : : * to break in several ways. It must always be updated when new
9 : : * updates are made to the main siginfo_t, and
10 : : * copy_siginfo_to_user32() must be updated when the
11 : : * (arch-independent) copy_siginfo_to_user() is updated.
12 : : *
13 : : * It is also easy to put a new member in the compat_siginfo_t
14 : : * which has implicit alignment which can move internal structure
15 : : * alignment around breaking the ABI. This can happen if you,
16 : : * for instance, put a plain 64-bit value in there.
17 : : */
18 : 238043 : static inline void signal_compat_build_tests(void)
19 : : {
20 : 238043 : int _sifields_offset = offsetof(compat_siginfo_t, _sifields);
21 : :
22 : : /*
23 : : * If adding a new si_code, there is probably new data in
24 : : * the siginfo. Make sure folks bumping the si_code
25 : : * limits also have to look at this code. Make sure any
26 : : * new fields are handled in copy_siginfo_to_user32()!
27 : : */
28 : 238043 : BUILD_BUG_ON(NSIGILL != 11);
29 : 238043 : BUILD_BUG_ON(NSIGFPE != 15);
30 : 238043 : BUILD_BUG_ON(NSIGSEGV != 7);
31 : 238043 : BUILD_BUG_ON(NSIGBUS != 5);
32 : 238043 : BUILD_BUG_ON(NSIGTRAP != 5);
33 : 238043 : BUILD_BUG_ON(NSIGCHLD != 6);
34 : 238043 : BUILD_BUG_ON(NSIGSYS != 1);
35 : :
36 : : /* This is part of the ABI and can never change in size: */
37 : 238043 : BUILD_BUG_ON(sizeof(compat_siginfo_t) != 128);
38 : : /*
39 : : * The offsets of all the (unioned) si_fields are fixed
40 : : * in the ABI, of course. Make sure none of them ever
41 : : * move and are always at the beginning:
42 : : */
43 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
44 : : #define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
45 : :
46 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
47 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
48 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_code) != 8);
49 : :
50 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_signo) != 0);
51 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_errno) != 4);
52 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_code) != 8);
53 : : /*
54 : : * Ensure that the size of each si_field never changes.
55 : : * If it does, it is a sign that the
56 : : * copy_siginfo_to_user32() code below needs to updated
57 : : * along with the size in the CHECK_SI_SIZE().
58 : : *
59 : : * We repeat this check for both the generic and compat
60 : : * siginfos.
61 : : *
62 : : * Note: it is OK for these to grow as long as the whole
63 : : * structure stays within the padding size (checked
64 : : * above).
65 : : */
66 : : #define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((compat_siginfo_t *)0)->_sifields.name))
67 : : #define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((siginfo_t *)0)->_sifields.name))
68 : :
69 : 238043 : CHECK_CSI_OFFSET(_kill);
70 : 238043 : CHECK_CSI_SIZE (_kill, 2*sizeof(int));
71 : 238043 : CHECK_SI_SIZE (_kill, 2*sizeof(int));
72 : :
73 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
74 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
75 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0xC);
76 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
77 : :
78 : 238043 : CHECK_CSI_OFFSET(_timer);
79 : 238043 : CHECK_CSI_SIZE (_timer, 3*sizeof(int));
80 : 238043 : CHECK_SI_SIZE (_timer, 6*sizeof(int));
81 : :
82 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_tid) != 0x10);
83 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x14);
84 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
85 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_tid) != 0x0C);
86 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_overrun) != 0x10);
87 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
88 : :
89 : 238043 : CHECK_CSI_OFFSET(_rt);
90 : 238043 : CHECK_CSI_SIZE (_rt, 3*sizeof(int));
91 : 238043 : CHECK_SI_SIZE (_rt, 4*sizeof(int));
92 : :
93 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
94 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
95 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
96 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0x0C);
97 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
98 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
99 : :
100 : 238043 : CHECK_CSI_OFFSET(_sigchld);
101 : 238043 : CHECK_CSI_SIZE (_sigchld, 5*sizeof(int));
102 : 238043 : CHECK_SI_SIZE (_sigchld, 8*sizeof(int));
103 : :
104 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
105 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
106 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x18);
107 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_utime) != 0x20);
108 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_stime) != 0x28);
109 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0x0C);
110 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
111 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_status) != 0x14);
112 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_utime) != 0x18);
113 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_stime) != 0x1C);
114 : :
115 : : #ifdef CONFIG_X86_X32_ABI
116 : : CHECK_CSI_OFFSET(_sigchld_x32);
117 : : CHECK_CSI_SIZE (_sigchld_x32, 7*sizeof(int));
118 : : /* no _sigchld_x32 in the generic siginfo_t */
119 : : BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._utime) != 0x18);
120 : : BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._stime) != 0x20);
121 : : #endif
122 : :
123 : 238043 : CHECK_CSI_OFFSET(_sigfault);
124 : 238043 : CHECK_CSI_SIZE (_sigfault, 4*sizeof(int));
125 : 238043 : CHECK_SI_SIZE (_sigfault, 8*sizeof(int));
126 : :
127 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x10);
128 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr) != 0x0C);
129 : :
130 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x18);
131 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr_lsb) != 0x10);
132 : :
133 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x20);
134 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x28);
135 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_lower) != 0x14);
136 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_upper) != 0x18);
137 : :
138 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x20);
139 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pkey) != 0x14);
140 : :
141 : 238043 : CHECK_CSI_OFFSET(_sigpoll);
142 : 238043 : CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));
143 : 238043 : CHECK_SI_SIZE (_sigpoll, 4*sizeof(int));
144 : :
145 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_band) != 0x10);
146 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_fd) != 0x18);
147 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_band) != 0x0C);
148 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_fd) != 0x10);
149 : :
150 : 238043 : CHECK_CSI_OFFSET(_sigsys);
151 : 238043 : CHECK_CSI_SIZE (_sigsys, 3*sizeof(int));
152 : 238043 : CHECK_SI_SIZE (_sigsys, 4*sizeof(int));
153 : :
154 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x10);
155 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_syscall) != 0x18);
156 : 238043 : BUILD_BUG_ON(offsetof(siginfo_t, si_arch) != 0x1C);
157 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_call_addr) != 0x0C);
158 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_syscall) != 0x10);
159 : 238043 : BUILD_BUG_ON(offsetof(compat_siginfo_t, si_arch) != 0x14);
160 : :
161 : : /* any new si_fields should be added here */
162 : : }
163 : :
164 : 238043 : void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
165 : : {
166 : 238043 : signal_compat_build_tests();
167 : :
168 : : /* Don't leak in-kernel non-uapi flags to user-space */
169 [ + + ]: 238043 : if (oact)
170 : 94601 : oact->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
171 : :
172 [ + + ]: 238043 : if (!act)
173 : : return;
174 : :
175 : : /* Don't let flags to be set from userspace */
176 : 146484 : act->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
177 : :
178 [ - + ]: 146484 : if (in_ia32_syscall())
179 : 0 : act->sa.sa_flags |= SA_IA32_ABI;
180 : : if (in_x32_syscall())
181 : : act->sa.sa_flags |= SA_X32_ABI;
182 : : }
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