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authorHeiko Carstens <heiko.carstens@de.ibm.com>2008-04-17 07:45:57 +0200
committerHeiko Carstens <heiko.carstens@de.ibm.com>2008-04-17 07:46:56 +0200
commitde553438eb6c487f72d46019eb3821f6687ce011 (patch)
tree690fc48f89768c07dc0e338853ff7a93bac25a26 /arch/s390/kernel/signal.c
parent08a8a0c59e54f7eb80897c1e77efa4a541d11008 (diff)
[S390] Protect against sigaltstack wraparound.
This is just a port of 83bd01024b1fdfc41d9b758e5669e80fca72df66 "x86: protect against sigaltstack wraparound". Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/signal.c')
-rw-r--r--arch/s390/kernel/signal.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 4449bf32cbf..8c92191949c 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -235,6 +235,10 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
/* Default to using normal stack */
sp = regs->gprs[15];
+ /* Overflow on alternate signal stack gives SIGSEGV. */
+ if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
+ return (void __user *) -1UL;
+
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (! sas_ss_flags(sp))
@@ -270,6 +274,9 @@ static int setup_frame(int sig, struct k_sigaction *ka,
if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
goto give_sigsegv;
+ if (frame == (void __user *) -1UL)
+ goto give_sigsegv;
+
if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
goto give_sigsegv;
@@ -327,6 +334,9 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
goto give_sigsegv;
+ if (frame == (void __user *) -1UL)
+ goto give_sigsegv;
+
if (copy_siginfo_to_user(&frame->info, info))
goto give_sigsegv;