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authorDavid S. Miller <davem@davemloft.net>2008-05-07 18:54:05 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2008-05-15 07:50:00 -0700
commit742de58a7b519a51ea77153b6e053223eb6ccbaf (patch)
treea91b8caa8abfe155e7848bfd28f7a97e41a23d80
parent970a75dcfa7fd55dd911830d8772dbbf471c154d (diff)
sparc: Fix SA_ONSTACK signal handling.
[ Upstream commit: dc5dc7e6d71ca9fd1ea01a1418150af3b2937489 ] We need to be more liberal about the alignment of the buffer given to us by sigaltstack(). The user should not need to be mindful of all of the alignment constraints we have for the stack frame. This mirrors how we handle this situation in clone() as well. Also, we align the stack even in non-SA_ONSTACK cases so that signals due to bad stack alignment can be delivered properly. This makes such errors easier to debug and recover from. Finally, add the sanity check x86 has to make sure we won't overflow the signal stack. This fixes glibc testcases nptl/tst-cancel20.c and nptl/tst-cancelx20.c Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/sparc/kernel/signal.c20
-rw-r--r--arch/sparc64/kernel/signal.c21
-rw-r--r--arch/sparc64/kernel/signal32.c18
3 files changed, 51 insertions, 8 deletions
diff --git a/arch/sparc/kernel/signal.c b/arch/sparc/kernel/signal.c
index 9994cac95078..c80a232db6dd 100644
--- a/arch/sparc/kernel/signal.c
+++ b/arch/sparc/kernel/signal.c
@@ -345,15 +345,29 @@ 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);
}
diff --git a/arch/sparc64/kernel/signal.c b/arch/sparc64/kernel/signal.c
index 9d51956e8e2f..01b6f1821e34 100644
--- a/arch/sparc64/kernel/signal.c
+++ b/arch/sparc64/kernel/signal.c
@@ -377,16 +377,29 @@ save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
{
- unsigned long sp;
+ unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
- sp = regs->u_regs[UREG_FP] + STACK_BIAS;
+ /*
+ * 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 (ka->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);
}
diff --git a/arch/sparc64/kernel/signal32.c b/arch/sparc64/kernel/signal32.c
index 8c1c121330fb..c55b67c614b9 100644
--- a/arch/sparc64/kernel/signal32.c
+++ b/arch/sparc64/kernel/signal32.c
@@ -497,11 +497,27 @@ static void __user *get_sigframe(struct sigaction *sa, struct pt_regs *regs, uns
regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
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);
}