LXR linux/arch/x86/kernel/signal

   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 */
  18static inline void signal_compat_build_tests(void)
  19{
  20        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        BUILD_BUG_ON(NSIGILL  != 11);
  29        BUILD_BUG_ON(NSIGFPE  != 15);
  30        BUILD_BUG_ON(NSIGSEGV != 9);
  31        BUILD_BUG_ON(NSIGBUS  != 5);
  32        BUILD_BUG_ON(NSIGTRAP != 6);
  33        BUILD_BUG_ON(NSIGCHLD != 6);
  34        BUILD_BUG_ON(NSIGSYS  != 2);
  35
  36        /* This is part of the ABI and can never change in size: */
  37        BUILD_BUG_ON(sizeof(siginfo_t) != 128);
  38        BUILD_BUG_ON(sizeof(compat_siginfo_t) != 128);
  39
  40        /* This is a part of the ABI and can never change in alignment */
  41        BUILD_BUG_ON(__alignof__(siginfo_t) != 8);
  42        BUILD_BUG_ON(__alignof__(compat_siginfo_t) != 4);
  43
  44        /*
  45         * The offsets of all the (unioned) si_fields are fixed
  46         * in the ABI, of course.  Make sure none of them ever
  47         * move and are always at the beginning:
  48         */
  49        BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
  50#define CHECK_CSI_OFFSET(name)    BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
  51
  52        BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
  53        BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
  54        BUILD_BUG_ON(offsetof(siginfo_t, si_code)  != 8);
  55
  56        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_signo) != 0);
  57        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_errno) != 4);
  58        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_code)  != 8);
  59         /*
  60         * Ensure that the size of each si_field never changes.
  61         * If it does, it is a sign that the
  62         * copy_siginfo_to_user32() code below needs to updated
  63         * along with the size in the CHECK_SI_SIZE().
  64         *
  65         * We repeat this check for both the generic and compat
  66         * siginfos.
  67         *
  68         * Note: it is OK for these to grow as long as the whole
  69         * structure stays within the padding size (checked
  70         * above).
  71         */
  72#define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((compat_siginfo_t *)0)->_sifields.name))
  73#define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((siginfo_t *)0)->_sifields.name))
  74
  75        CHECK_CSI_OFFSET(_kill);
  76        CHECK_CSI_SIZE  (_kill, 2*sizeof(int));
  77        CHECK_SI_SIZE   (_kill, 2*sizeof(int));
  78
  79        BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
  80        BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
  81        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0xC);
  82        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
  83
  84        CHECK_CSI_OFFSET(_timer);
  85        CHECK_CSI_SIZE  (_timer, 3*sizeof(int));
  86        CHECK_SI_SIZE   (_timer, 6*sizeof(int));
  87
  88        BUILD_BUG_ON(offsetof(siginfo_t, si_tid)     != 0x10);
  89        BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x14);
  90        BUILD_BUG_ON(offsetof(siginfo_t, si_value)   != 0x18);
  91        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_tid)     != 0x0C);
  92        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_overrun) != 0x10);
  93        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value)   != 0x14);
  94
  95        CHECK_CSI_OFFSET(_rt);
  96        CHECK_CSI_SIZE  (_rt, 3*sizeof(int));
  97        CHECK_SI_SIZE   (_rt, 4*sizeof(int));
  98
  99        BUILD_BUG_ON(offsetof(siginfo_t, si_pid)   != 0x10);
 100        BUILD_BUG_ON(offsetof(siginfo_t, si_uid)   != 0x14);
 101        BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
 102        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid)   != 0x0C);
 103        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid)   != 0x10);
 104        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
 105
 106        CHECK_CSI_OFFSET(_sigchld);
 107        CHECK_CSI_SIZE  (_sigchld, 5*sizeof(int));
 108        CHECK_SI_SIZE   (_sigchld, 8*sizeof(int));
 109
 110        BUILD_BUG_ON(offsetof(siginfo_t, si_pid)    != 0x10);
 111        BUILD_BUG_ON(offsetof(siginfo_t, si_uid)    != 0x14);
 112        BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x18);
 113        BUILD_BUG_ON(offsetof(siginfo_t, si_utime)  != 0x20);
 114        BUILD_BUG_ON(offsetof(siginfo_t, si_stime)  != 0x28);
 115        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid)    != 0x0C);
 116        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid)    != 0x10);
 117        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_status) != 0x14);
 118        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_utime)  != 0x18);
 119        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_stime)  != 0x1C);
 120
 121#ifdef CONFIG_X86_X32_ABI
 122        CHECK_CSI_OFFSET(_sigchld_x32);
 123        CHECK_CSI_SIZE  (_sigchld_x32, 7*sizeof(int));
 124        /* no _sigchld_x32 in the generic siginfo_t */
 125        BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._utime)  != 0x18);
 126        BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._stime)  != 0x20);
 127#endif
 128
 129        CHECK_CSI_OFFSET(_sigfault);
 130        CHECK_CSI_SIZE  (_sigfault, 4*sizeof(int));
 131        CHECK_SI_SIZE   (_sigfault, 8*sizeof(int));
 132
 133        BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x10);
 134        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr) != 0x0C);
 135
 136        BUILD_BUG_ON(offsetof(siginfo_t, si_trapno) != 0x18);
 137        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_trapno) != 0x10);
 138
 139        BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x18);
 140        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr_lsb) != 0x10);
 141
 142        BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x20);
 143        BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x28);
 144        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_lower) != 0x14);
 145        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_upper) != 0x18);
 146
 147        BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x20);
 148        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pkey) != 0x14);
 149
 150        BUILD_BUG_ON(offsetof(siginfo_t, si_perf_data) != 0x18);
 151        BUILD_BUG_ON(offsetof(siginfo_t, si_perf_type) != 0x20);
 152        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf_data) != 0x10);
 153        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_perf_type) != 0x14);
 154
 155        CHECK_CSI_OFFSET(_sigpoll);
 156        CHECK_CSI_SIZE  (_sigpoll, 2*sizeof(int));
 157        CHECK_SI_SIZE   (_sigpoll, 4*sizeof(int));
 158
 159        BUILD_BUG_ON(offsetof(siginfo_t, si_band)   != 0x10);
 160        BUILD_BUG_ON(offsetof(siginfo_t, si_fd)     != 0x18);
 161        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_band) != 0x0C);
 162        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_fd)   != 0x10);
 163
 164        CHECK_CSI_OFFSET(_sigsys);
 165        CHECK_CSI_SIZE  (_sigsys, 3*sizeof(int));
 166        CHECK_SI_SIZE   (_sigsys, 4*sizeof(int));
 167
 168        BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x10);
 169        BUILD_BUG_ON(offsetof(siginfo_t, si_syscall)   != 0x18);
 170        BUILD_BUG_ON(offsetof(siginfo_t, si_arch)      != 0x1C);
 171        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_call_addr) != 0x0C);
 172        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_syscall)   != 0x10);
 173        BUILD_BUG_ON(offsetof(compat_siginfo_t, si_arch)      != 0x14);
 174
 175        /* any new si_fields should be added here */
 176}
 177
 178void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
 179{
 180        signal_compat_build_tests();
 181
 182        if (!act)
 183                return;
 184
 185        if (in_ia32_syscall())
 186                act->sa.sa_flags |= SA_IA32_ABI;
 187        if (in_x32_syscall())
 188                act->sa.sa_flags |= SA_X32_ABI;
 189}
 190