322740efbb
Commit db2f24dc24
was plain wrong. I did not realize the we are
allowed to loop here.
In fact we have to loop and must not return to userspace
before all SIGSEGVs have been delivered.
Other archs do this directly in their entry code, UML
does it here.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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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 <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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EXPORT_SYMBOL(block_signals);
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EXPORT_SYMBOL(unblock_signals);
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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 ((current->ptrace & PT_DTRACE) && (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 (current->ptrace & PT_DTRACE)
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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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