commit b4b6d4a02fa8aa8187d426b508fb7f3b69df0dcc
author Andrew Scull <ascull@google.com> Wed Jan 02 15:54:55 2019 +0000
committer Andrew Scull <ascull@google.com> Wed Jan 02 15:54:55 2019 +0000
tree fdf4498bc30cb80757eaf20b46ea866b23141a93

v4.19.13 snapshot.

arch/um/kernel/ptrace.c

diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
new file mode 100644
index 0000000..1a1d88a
--- /dev/null
+++ b/arch/um/kernel/ptrace.c
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/audit.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/tracehook.h>
+#include <linux/uaccess.h>
+#include <asm/ptrace-abi.h>
+
+void user_enable_single_step(struct task_struct *child)
+{
+	child->ptrace |= PT_DTRACE;
+	child->thread.singlestep_syscall = 0;
+
+#ifdef SUBARCH_SET_SINGLESTEPPING
+	SUBARCH_SET_SINGLESTEPPING(child, 1);
+#endif
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+	child->ptrace &= ~PT_DTRACE;
+	child->thread.singlestep_syscall = 0;
+
+#ifdef SUBARCH_SET_SINGLESTEPPING
+	SUBARCH_SET_SINGLESTEPPING(child, 0);
+#endif
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ */
+void ptrace_disable(struct task_struct *child)
+{
+	user_disable_single_step(child);
+}
+
+extern int peek_user(struct task_struct * child, long addr, long data);
+extern int poke_user(struct task_struct * child, long addr, long data);
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	int i, ret;
+	unsigned long __user *p = (void __user *)data;
+	void __user *vp = p;
+
+	switch (request) {
+	/* read the word at location addr in the USER area. */
+	case PTRACE_PEEKUSR:
+		ret = peek_user(child, addr, data);
+		break;
+
+	/* write the word at location addr in the USER area */
+	case PTRACE_POKEUSR:
+		ret = poke_user(child, addr, data);
+		break;
+
+	case PTRACE_SYSEMU:
+	case PTRACE_SYSEMU_SINGLESTEP:
+		ret = -EIO;
+		break;
+
+#ifdef PTRACE_GETREGS
+	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
+		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
+			__put_user(getreg(child, i), p);
+			p++;
+		}
+		ret = 0;
+		break;
+	}
+#endif
+#ifdef PTRACE_SETREGS
+	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
+		unsigned long tmp = 0;
+		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
+			__get_user(tmp, p);
+			putreg(child, i, tmp);
+			p++;
+		}
+		ret = 0;
+		break;
+	}
+#endif
+	case PTRACE_GET_THREAD_AREA:
+		ret = ptrace_get_thread_area(child, addr, vp);
+		break;
+
+	case PTRACE_SET_THREAD_AREA:
+		ret = ptrace_set_thread_area(child, addr, vp);
+		break;
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		if (ret == -EIO)
+			ret = subarch_ptrace(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+
+static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
+		  int error_code)
+{
+	/* Send us the fake SIGTRAP */
+	force_sig_fault(SIGTRAP, TRAP_BRKPT,
+			/* User-mode eip? */
+			UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL, tsk);
+}
+
+/*
+ * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
+ * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+ */
+int syscall_trace_enter(struct pt_regs *regs)
+{
+	audit_syscall_entry(UPT_SYSCALL_NR(&regs->regs),
+			    UPT_SYSCALL_ARG1(&regs->regs),
+			    UPT_SYSCALL_ARG2(&regs->regs),
+			    UPT_SYSCALL_ARG3(&regs->regs),
+			    UPT_SYSCALL_ARG4(&regs->regs));
+
+	if (!test_thread_flag(TIF_SYSCALL_TRACE))
+		return 0;
+
+	return tracehook_report_syscall_entry(regs);
+}
+
+void syscall_trace_leave(struct pt_regs *regs)
+{
+	int ptraced = current->ptrace;
+
+	audit_syscall_exit(regs);
+
+	/* Fake a debug trap */
+	if (ptraced & PT_DTRACE)
+		send_sigtrap(current, &regs->regs, 0);
+
+	if (!test_thread_flag(TIF_SYSCALL_TRACE))
+		return;
+
+	tracehook_report_syscall_exit(regs, 0);
+	/* force do_signal() --> is_syscall() */
+	if (ptraced & PT_PTRACED)
+		set_thread_flag(TIF_SIGPENDING);
+}