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* [PATCH 3/5] signal(x86_ia32): add a signal stack overflow check
@ 2008-02-18 10:25 Shi Weihua
2008-02-19 2:23 ` Shi Weihua
0 siblings, 1 reply; 3+ messages in thread
From: Shi Weihua @ 2008-02-18 10:25 UTC (permalink / raw)
To: Ingo Molnar; +Cc: linux-kernel, Thomas Gleixner, H. Peter Anvin
The similar check has been added to x86_32(i386) in commit
id 83bd01024b1fdfc41d9b758e5669e80fca72df66.
So we add this check to x86_ia32 and improve it a liitle bit in that
we need to check for stack overflow only when the signal is on stack.
Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
---
--- linux-2.6.25-rc2.orig/arch/x86/ia32/ia32_signal.c 2008-02-16 04:57:20.000000000 +0800
+++ linux-2.6.25-rc2/arch/x86/ia32/ia32_signal.c 2008-02-18 18:07:01.000000000 +0800
@@ -406,8 +406,19 @@ static void __user *get_sigframe(struct
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
- if (sas_ss_flags(sp) == 0)
+ int onstack = sas_ss_flags(sp);
+
+ if (onstack == 0)
sp = current->sas_ss_sp + current->sas_ss_size;
+ else if (onstack == SS_ONSTACK) {
+ /*
+ * If we are on the alternate signal stack and would
+ * overflow it, don't return an always-bogus address
+ * instead so we will die with SIGSEGV.
+ */
+ if (!likely(on_sig_stack(sp - frame_size)))
+ return (void __user *) -1L;
+ }
}
/* This is the legacy signal stack switching. */
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 3/5] signal(x86_ia32): add a signal stack overflow check
2008-02-18 10:25 [PATCH 3/5] signal(x86_ia32): add a signal stack overflow check Shi Weihua
@ 2008-02-19 2:23 ` Shi Weihua
2008-02-19 11:11 ` Ingo Molnar
0 siblings, 1 reply; 3+ messages in thread
From: Shi Weihua @ 2008-02-19 2:23 UTC (permalink / raw)
To: Ingo Molnar; +Cc: linux-kernel, Thomas Gleixner, H. Peter Anvin
The similar check has been added to x86_32(i386) in commit
id 83bd01024b1fdfc41d9b758e5669e80fca72df66.
So we add this check to x86_ia32 and improve it a liitle bit in that
we need to check for stack overflow only when the signal is on stack.
Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
---
The previous patch has a comment mistake. Now I correct it.
---
--- linux-2.6.25-rc2.orig/arch/x86/ia32/ia32_signal.c 2008-02-16 04:57:20.000000000 +0800
+++ linux-2.6.25-rc2/arch/x86/ia32/ia32_signal.c 2008-02-19 09:56:43.000000000 +0800
@@ -406,8 +406,19 @@ static void __user *get_sigframe(struct
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
- if (sas_ss_flags(sp) == 0)
+ int onstack = sas_ss_flags(sp);
+
+ if (onstack == 0)
sp = current->sas_ss_sp + current->sas_ss_size;
+ else if (onstack == SS_ONSTACK) {
+ /*
+ * If we are on the alternate signal stack and would
+ * overflow it, don't. Return an always-bogus address
+ * instead so we will die with SIGSEGV.
+ */
+ if (!likely(on_sig_stack(sp - frame_size)))
+ return (void __user *) -1L;
+ }
}
/* This is the legacy signal stack switching. */
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 3/5] signal(x86_ia32): add a signal stack overflow check
2008-02-19 2:23 ` Shi Weihua
@ 2008-02-19 11:11 ` Ingo Molnar
0 siblings, 0 replies; 3+ messages in thread
From: Ingo Molnar @ 2008-02-19 11:11 UTC (permalink / raw)
To: Shi Weihua; +Cc: linux-kernel, Thomas Gleixner, H. Peter Anvin
* Shi Weihua <shiwh@cn.fujitsu.com> wrote:
> The similar check has been added to x86_32(i386) in commit id
> 83bd01024b1fdfc41d9b758e5669e80fca72df66. So we add this check to
> x86_ia32 and improve it a liitle bit in that we need to check for
> stack overflow only when the signal is on stack.
thanks, applied.
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-02-19 11:12 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2008-02-18 10:25 [PATCH 3/5] signal(x86_ia32): add a signal stack overflow check Shi Weihua
2008-02-19 2:23 ` Shi Weihua
2008-02-19 11:11 ` Ingo Molnar
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