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c200e4bb44
User mode linux is the last user of the PT_DTRACE flag. Using the flag to indicate single stepping is a little confusing and worse changing tsk->ptrace without locking could potentionally cause problems. So use a thread info flag with a better name instead of flag in tsk->ptrace. Remove the definition PT_DTRACE as uml is the last user. Cc: stable@vger.kernel.org Acked-by: Johannes Berg <johannes@sipsolutions.net> Tested-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20220505182645.497868-3-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
142 lines
3.3 KiB
C
142 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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*/
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#include <linux/module.h>
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#include <linux/ptrace.h>
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#include <linux/sched.h>
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#include <linux/ftrace.h>
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#include <asm/siginfo.h>
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#include <asm/signal.h>
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#include <asm/unistd.h>
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#include <frame_kern.h>
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#include <kern_util.h>
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#include <os.h>
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EXPORT_SYMBOL(block_signals);
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EXPORT_SYMBOL(unblock_signals);
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void block_signals_trace(void)
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{
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block_signals();
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if (current_thread_info())
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trace_hardirqs_off();
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}
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void unblock_signals_trace(void)
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{
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if (current_thread_info())
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trace_hardirqs_on();
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unblock_signals();
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}
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void um_trace_signals_on(void)
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{
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if (current_thread_info())
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trace_hardirqs_on();
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}
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void um_trace_signals_off(void)
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{
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if (current_thread_info())
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trace_hardirqs_off();
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}
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/*
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* OK, we're invoking a handler
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*/
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static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
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{
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sigset_t *oldset = sigmask_to_save();
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int singlestep = 0;
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unsigned long sp;
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int err;
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if (test_thread_flag(TIF_SINGLESTEP) && (current->ptrace & PT_PTRACED))
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singlestep = 1;
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/* Did we come from a system call? */
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if (PT_REGS_SYSCALL_NR(regs) >= 0) {
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/* If so, check system call restarting.. */
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switch (PT_REGS_SYSCALL_RET(regs)) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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PT_REGS_SYSCALL_RET(regs) = -EINTR;
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break;
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case -ERESTARTSYS:
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if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
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PT_REGS_SYSCALL_RET(regs) = -EINTR;
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break;
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}
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fallthrough;
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case -ERESTARTNOINTR:
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PT_REGS_RESTART_SYSCALL(regs);
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PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
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break;
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}
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}
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sp = PT_REGS_SP(regs);
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if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
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sp = current->sas_ss_sp + current->sas_ss_size;
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#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
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if (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
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err = setup_signal_stack_sc(sp, ksig, regs, oldset);
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else
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#endif
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err = setup_signal_stack_si(sp, ksig, regs, oldset);
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signal_setup_done(err, ksig, singlestep);
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}
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void do_signal(struct pt_regs *regs)
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{
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struct ksignal ksig;
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int handled_sig = 0;
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while (get_signal(&ksig)) {
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handled_sig = 1;
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/* Whee! Actually deliver the signal. */
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handle_signal(&ksig, regs);
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}
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/* Did we come from a system call? */
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if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
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/* Restart the system call - no handlers present */
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switch (PT_REGS_SYSCALL_RET(regs)) {
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
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PT_REGS_RESTART_SYSCALL(regs);
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break;
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case -ERESTART_RESTARTBLOCK:
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PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
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PT_REGS_RESTART_SYSCALL(regs);
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break;
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}
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}
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/*
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* This closes a way to execute a system call on the host. If
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* you set a breakpoint on a system call instruction and singlestep
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* from it, the tracing thread used to PTRACE_SINGLESTEP the process
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* rather than PTRACE_SYSCALL it, allowing the system call to execute
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* on the host. The tracing thread will check this flag and
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* PTRACE_SYSCALL if necessary.
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*/
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if (test_thread_flag(TIF_SINGLESTEP))
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current->thread.singlestep_syscall =
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is_syscall(PT_REGS_IP(¤t->thread.regs));
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/*
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* if there's no signal to deliver, we just put the saved sigmask
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* back
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*/
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if (!handled_sig)
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restore_saved_sigmask();
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}
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