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hurd: Fix using altstack while in an RPC call to be aborted

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* sysdeps/mach/hurd/i386/trampoline.c (_hurd_setup_sighandler): Always check
for interrupted code being with esp pointing at mach_msg arguments, even
when using an altstack. If we need to abort the RPC we will need
this.
This commit is contained in:
Samuel Thibault 2019-12-11 00:23:00 +01:00
parent 83fe078130
commit e46efff895
1 changed files with 14 additions and 13 deletions
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27
sysdeps/mach/hurd/i386/trampoline.c
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@ -74,12 +74,6 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
interrupted RPC frame. */
state->basic.esp = state->basic.uesp;
if ((ss->actions[signo].sa_flags & SA_ONSTACK)
&& !(ss->sigaltstack.ss_flags & (SS_DISABLE|SS_ONSTACK)))
{
sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
ss->sigaltstack.ss_flags |= SS_ONSTACK;
}
/* This code has intimate knowledge of the special mach_msg system call
done in intr-msg.c; that code does (see intr-msg.h):
movl %esp, %ecx
@ -91,13 +85,20 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
We must check for the window during which %esp points at the
mach_msg arguments. The space below until %ecx is used by
the _hurd_intr_rpc_mach_msg frame, and must not be clobbered. */
else if (state->basic.eip >= (int) &_hurd_intr_rpc_msg_cx_sp
&& state->basic.eip < (int) &_hurd_intr_rpc_msg_sp_restored)
/* The SP now points at the mach_msg args, but there is more stack
space used below it. The real SP is saved in %ecx; we must push the
new frame below there, and restore that value as the SP on
sigreturn. */
sigsp = (char *) (state->basic.uesp = state->basic.ecx);
if (state->basic.eip >= (int) &_hurd_intr_rpc_msg_cx_sp
&& state->basic.eip < (int) &_hurd_intr_rpc_msg_sp_restored)
/* The SP now points at the mach_msg args, but there is more stack
space used below it. The real SP is saved in %ecx; we must push the
new frame below there (if not on the altstack), and restore that value as
the SP on sigreturn. */
state->basic.uesp = state->basic.ecx;
if ((ss->actions[signo].sa_flags & SA_ONSTACK)
&& !(ss->sigaltstack.ss_flags & (SS_DISABLE|SS_ONSTACK)))
{
sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
ss->sigaltstack.ss_flags |= SS_ONSTACK;
}
else
sigsp = (char *) state->basic.uesp;