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-rw-r--r--arch/sparc/kernel/signal.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/arch/sparc/kernel/signal.c b/arch/sparc/kernel/signal.c
index 3c312290c3c..368157926d2 100644
--- a/arch/sparc/kernel/signal.c
+++ b/arch/sparc/kernel/signal.c
@@ -245,15 +245,29 @@ static inline int invalid_frame_pointer(void __user *fp, int fplen)
static inline void __user *get_sigframe(struct sigaction *sa, struct pt_regs *regs, unsigned long framesize)
{
- unsigned long sp;
+ unsigned long sp = regs->u_regs[UREG_FP];
- sp = regs->u_regs[UREG_FP];
+ /*
+ * 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 (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
+ return (void __user *) -1L;
/* This is the X/Open sanctioned signal stack switching. */
if (sa->sa_flags & SA_ONSTACK) {
- if (!on_sig_stack(sp) && !((current->sas_ss_sp + current->sas_ss_size) & 7))
+ if (sas_ss_flags(sp) == 0)
sp = current->sas_ss_sp + current->sas_ss_size;
}
+
+ /* Always align the stack frame. This handles two cases. First,
+ * sigaltstack need not be mindful of platform specific stack
+ * alignment. Second, if we took this signal because the stack
+ * is not aligned properly, we'd like to take the signal cleanly
+ * and report that.
+ */
+ sp &= ~7UL;
+
return (void __user *)(sp - framesize);
}