1 #include <linux/compat.h>
2 #include <linux/uaccess.h>
3 #include <linux/ptrace.h>
6 * The compat_siginfo_t structure and handing code is very easy
7 * to break in several ways. It must always be updated when new
8 * updates are made to the main siginfo_t, and
9 * copy_siginfo_to_user32() must be updated when the
10 * (arch-independent) copy_siginfo_to_user() is updated.
12 * It is also easy to put a new member in the compat_siginfo_t
13 * which has implicit alignment which can move internal structure
14 * alignment around breaking the ABI. This can happen if you,
15 * for instance, put a plain 64-bit value in there.
17 static inline void signal_compat_build_tests(void)
19 int _sifields_offset = offsetof(compat_siginfo_t, _sifields);
22 * If adding a new si_code, there is probably new data in
23 * the siginfo. Make sure folks bumping the si_code
24 * limits also have to look at this code. Make sure any
25 * new fields are handled in copy_siginfo_to_user32()!
27 BUILD_BUG_ON(NSIGILL != 8);
28 BUILD_BUG_ON(NSIGFPE != 8);
29 BUILD_BUG_ON(NSIGSEGV != 4);
30 BUILD_BUG_ON(NSIGBUS != 5);
31 BUILD_BUG_ON(NSIGTRAP != 4);
32 BUILD_BUG_ON(NSIGCHLD != 6);
33 BUILD_BUG_ON(NSIGSYS != 1);
35 /* This is part of the ABI and can never change in size: */
36 BUILD_BUG_ON(sizeof(compat_siginfo_t) != 128);
38 * The offsets of all the (unioned) si_fields are fixed
39 * in the ABI, of course. Make sure none of them ever
40 * move and are always at the beginning:
42 BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
43 #define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
46 * Ensure that the size of each si_field never changes.
47 * If it does, it is a sign that the
48 * copy_siginfo_to_user32() code below needs to updated
49 * along with the size in the CHECK_SI_SIZE().
51 * We repeat this check for both the generic and compat
54 * Note: it is OK for these to grow as long as the whole
55 * structure stays within the padding size (checked
58 #define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((compat_siginfo_t *)0)->_sifields.name))
59 #define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((siginfo_t *)0)->_sifields.name))
61 CHECK_CSI_OFFSET(_kill);
62 CHECK_CSI_SIZE (_kill, 2*sizeof(int));
63 CHECK_SI_SIZE (_kill, 2*sizeof(int));
65 CHECK_CSI_OFFSET(_timer);
66 CHECK_CSI_SIZE (_timer, 5*sizeof(int));
67 CHECK_SI_SIZE (_timer, 6*sizeof(int));
69 CHECK_CSI_OFFSET(_rt);
70 CHECK_CSI_SIZE (_rt, 3*sizeof(int));
71 CHECK_SI_SIZE (_rt, 4*sizeof(int));
73 CHECK_CSI_OFFSET(_sigchld);
74 CHECK_CSI_SIZE (_sigchld, 5*sizeof(int));
75 CHECK_SI_SIZE (_sigchld, 8*sizeof(int));
77 CHECK_CSI_OFFSET(_sigchld_x32);
78 CHECK_CSI_SIZE (_sigchld_x32, 7*sizeof(int));
79 /* no _sigchld_x32 in the generic siginfo_t */
81 CHECK_CSI_OFFSET(_sigfault);
82 CHECK_CSI_SIZE (_sigfault, 4*sizeof(int));
83 CHECK_SI_SIZE (_sigfault, 8*sizeof(int));
85 CHECK_CSI_OFFSET(_sigpoll);
86 CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));
87 CHECK_SI_SIZE (_sigpoll, 4*sizeof(int));
89 CHECK_CSI_OFFSET(_sigsys);
90 CHECK_CSI_SIZE (_sigsys, 3*sizeof(int));
91 CHECK_SI_SIZE (_sigsys, 4*sizeof(int));
93 /* any new si_fields should be added here */
96 void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
98 /* Don't leak in-kernel non-uapi flags to user-space */
100 oact->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
105 /* Don't let flags to be set from userspace */
106 act->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
108 if (in_ia32_syscall())
109 act->sa.sa_flags |= SA_IA32_ABI;
110 if (in_x32_syscall())
111 act->sa.sa_flags |= SA_X32_ABI;
114 int __copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from,
119 signal_compat_build_tests();
121 if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
125 /* If you change siginfo_t structure, please make sure that
126 this code is fixed accordingly.
127 It should never copy any pad contained in the structure
128 to avoid security leaks, but must copy the generic
129 3 ints plus the relevant union member. */
130 put_user_ex(from->si_signo, &to->si_signo);
131 put_user_ex(from->si_errno, &to->si_errno);
132 put_user_ex((short)from->si_code, &to->si_code);
134 if (from->si_code < 0) {
135 put_user_ex(from->si_pid, &to->si_pid);
136 put_user_ex(from->si_uid, &to->si_uid);
137 put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
140 * First 32bits of unions are always present:
141 * si_pid === si_band === si_tid === si_addr(LS half)
143 put_user_ex(from->_sifields._pad[0],
144 &to->_sifields._pad[0]);
145 switch (from->si_code >> 16) {
146 case __SI_FAULT >> 16:
147 if (from->si_signo == SIGBUS &&
148 (from->si_code == BUS_MCEERR_AR ||
149 from->si_code == BUS_MCEERR_AO))
150 put_user_ex(from->si_addr_lsb, &to->si_addr_lsb);
152 if (from->si_signo == SIGSEGV) {
153 if (from->si_code == SEGV_BNDERR) {
154 compat_uptr_t lower = (unsigned long)&to->si_lower;
155 compat_uptr_t upper = (unsigned long)&to->si_upper;
156 put_user_ex(lower, &to->si_lower);
157 put_user_ex(upper, &to->si_upper);
159 if (from->si_code == SEGV_PKUERR)
160 put_user_ex(from->si_pkey, &to->si_pkey);
164 put_user_ex(from->si_syscall, &to->si_syscall);
165 put_user_ex(from->si_arch, &to->si_arch);
167 case __SI_CHLD >> 16:
169 put_user_ex(from->si_utime, &to->si_utime);
170 put_user_ex(from->si_stime, &to->si_stime);
172 put_user_ex(from->si_utime, &to->_sifields._sigchld_x32._utime);
173 put_user_ex(from->si_stime, &to->_sifields._sigchld_x32._stime);
175 put_user_ex(from->si_status, &to->si_status);
178 case __SI_KILL >> 16:
179 put_user_ex(from->si_uid, &to->si_uid);
181 case __SI_POLL >> 16:
182 put_user_ex(from->si_fd, &to->si_fd);
184 case __SI_TIMER >> 16:
185 put_user_ex(from->si_overrun, &to->si_overrun);
186 put_user_ex(ptr_to_compat(from->si_ptr),
189 /* This is not generated by the kernel as of now. */
191 case __SI_MESGQ >> 16:
192 put_user_ex(from->si_uid, &to->si_uid);
193 put_user_ex(from->si_int, &to->si_int);
197 } put_user_catch(err);
202 /* from syscall's path, where we know the ABI */
203 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
205 return __copy_siginfo_to_user32(to, from, in_x32_syscall());
208 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
213 if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
217 get_user_ex(to->si_signo, &from->si_signo);
218 get_user_ex(to->si_errno, &from->si_errno);
219 get_user_ex(to->si_code, &from->si_code);
221 get_user_ex(to->si_pid, &from->si_pid);
222 get_user_ex(to->si_uid, &from->si_uid);
223 get_user_ex(ptr32, &from->si_ptr);
224 to->si_ptr = compat_ptr(ptr32);
225 } get_user_catch(err);