v4.19.13 snapshot.
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
new file mode 100644
index 0000000..9ccbf05
--- /dev/null
+++ b/arch/x86/kernel/signal_compat.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compat.h>
+#include <linux/uaccess.h>
+#include <linux/ptrace.h>
+
+/*
+ * The compat_siginfo_t structure and handing code is very easy
+ * to break in several ways. It must always be updated when new
+ * updates are made to the main siginfo_t, and
+ * copy_siginfo_to_user32() must be updated when the
+ * (arch-independent) copy_siginfo_to_user() is updated.
+ *
+ * It is also easy to put a new member in the compat_siginfo_t
+ * which has implicit alignment which can move internal structure
+ * alignment around breaking the ABI. This can happen if you,
+ * for instance, put a plain 64-bit value in there.
+ */
+static inline void signal_compat_build_tests(void)
+{
+ int _sifields_offset = offsetof(compat_siginfo_t, _sifields);
+
+ /*
+ * If adding a new si_code, there is probably new data in
+ * the siginfo. Make sure folks bumping the si_code
+ * limits also have to look at this code. Make sure any
+ * new fields are handled in copy_siginfo_to_user32()!
+ */
+ BUILD_BUG_ON(NSIGILL != 11);
+ BUILD_BUG_ON(NSIGFPE != 15);
+ BUILD_BUG_ON(NSIGSEGV != 7);
+ BUILD_BUG_ON(NSIGBUS != 5);
+ BUILD_BUG_ON(NSIGTRAP != 5);
+ BUILD_BUG_ON(NSIGCHLD != 6);
+ BUILD_BUG_ON(NSIGSYS != 1);
+
+ /* This is part of the ABI and can never change in size: */
+ BUILD_BUG_ON(sizeof(compat_siginfo_t) != 128);
+ /*
+ * The offsets of all the (unioned) si_fields are fixed
+ * in the ABI, of course. Make sure none of them ever
+ * move and are always at the beginning:
+ */
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
+#define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_code) != 8);
+
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_signo) != 0);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_errno) != 4);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_code) != 8);
+ /*
+ * Ensure that the size of each si_field never changes.
+ * If it does, it is a sign that the
+ * copy_siginfo_to_user32() code below needs to updated
+ * along with the size in the CHECK_SI_SIZE().
+ *
+ * We repeat this check for both the generic and compat
+ * siginfos.
+ *
+ * Note: it is OK for these to grow as long as the whole
+ * structure stays within the padding size (checked
+ * above).
+ */
+#define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((compat_siginfo_t *)0)->_sifields.name))
+#define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((siginfo_t *)0)->_sifields.name))
+
+ CHECK_CSI_OFFSET(_kill);
+ CHECK_CSI_SIZE (_kill, 2*sizeof(int));
+ CHECK_SI_SIZE (_kill, 2*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0xC);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
+
+ CHECK_CSI_OFFSET(_timer);
+ CHECK_CSI_SIZE (_timer, 3*sizeof(int));
+ CHECK_SI_SIZE (_timer, 6*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_tid) != 0x10);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x14);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_tid) != 0x0C);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_overrun) != 0x10);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
+
+ CHECK_CSI_OFFSET(_rt);
+ CHECK_CSI_SIZE (_rt, 3*sizeof(int));
+ CHECK_SI_SIZE (_rt, 4*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0x0C);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_value) != 0x14);
+
+ CHECK_CSI_OFFSET(_sigchld);
+ CHECK_CSI_SIZE (_sigchld, 5*sizeof(int));
+ CHECK_SI_SIZE (_sigchld, 8*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x10);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x14);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x18);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_utime) != 0x20);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_stime) != 0x28);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pid) != 0x0C);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_uid) != 0x10);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_status) != 0x14);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_utime) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_stime) != 0x1C);
+
+#ifdef CONFIG_X86_X32_ABI
+ CHECK_CSI_OFFSET(_sigchld_x32);
+ CHECK_CSI_SIZE (_sigchld_x32, 7*sizeof(int));
+ /* no _sigchld_x32 in the generic siginfo_t */
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._utime) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields._sigchld_x32._stime) != 0x20);
+#endif
+
+ CHECK_CSI_OFFSET(_sigfault);
+ CHECK_CSI_SIZE (_sigfault, 4*sizeof(int));
+ CHECK_SI_SIZE (_sigfault, 8*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x10);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr) != 0x0C);
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_addr_lsb) != 0x10);
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x20);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x28);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_lower) != 0x14);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_upper) != 0x18);
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x20);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_pkey) != 0x14);
+
+ CHECK_CSI_OFFSET(_sigpoll);
+ CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));
+ CHECK_SI_SIZE (_sigpoll, 4*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_band) != 0x10);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_fd) != 0x18);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_band) != 0x0C);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_fd) != 0x10);
+
+ CHECK_CSI_OFFSET(_sigsys);
+ CHECK_CSI_SIZE (_sigsys, 3*sizeof(int));
+ CHECK_SI_SIZE (_sigsys, 4*sizeof(int));
+
+ BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x10);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_syscall) != 0x18);
+ BUILD_BUG_ON(offsetof(siginfo_t, si_arch) != 0x1C);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_call_addr) != 0x0C);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_syscall) != 0x10);
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, si_arch) != 0x14);
+
+ /* any new si_fields should be added here */
+}
+
+void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
+{
+ signal_compat_build_tests();
+
+ /* Don't leak in-kernel non-uapi flags to user-space */
+ if (oact)
+ oact->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
+
+ if (!act)
+ return;
+
+ /* Don't let flags to be set from userspace */
+ act->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
+
+ if (in_ia32_syscall())
+ act->sa.sa_flags |= SA_IA32_ABI;
+ if (in_x32_syscall())
+ act->sa.sa_flags |= SA_X32_ABI;
+}