4.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
commit 8d4bd0ed0439dfc780aab801a085961925ed6838 upstream.
The uc_sigmask in the ucontext structure is an array of words to keep
the 64 signal bits (or 1024 if you ask glibc but the kernel sigset_t
only has 64 bits).
For 64 bit the sigset_t contains a single 8 byte word, but for 31 bit
there are two 4 byte words. The compat signal handler code uses a
simple copy of the 64 bit sigset_t to the 31 bit compat_sigset_t.
As s390 is a big-endian architecture this is incorrect, the two words
in the 31 bit sigset_t array need to be swapped.
Reported-by: Stefan Liebler <stli@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kernel/compat_signal.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -48,6 +48,19 @@ typedef struct
struct ucontext32 uc;
} rt_sigframe32;
+static inline void sigset_to_sigset32(unsigned long *set64,
+ compat_sigset_word *set32)
+{
+ set32[0] = (compat_sigset_word) set64[0];
+ set32[1] = (compat_sigset_word)(set64[0] >> 32);
+}
+
+static inline void sigset32_to_sigset(compat_sigset_word *set32,
+ unsigned long *set64)
+{
+ set64[0] = (unsigned long) set32[0] | ((unsigned long) set32[1] << 32);
+}
+
int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
{
int err;
@@ -303,10 +316,12 @@ COMPAT_SYSCALL_DEFINE0(sigreturn)
{
struct pt_regs *regs = task_pt_regs(current);
sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
+ compat_sigset_t cset;
sigset_t set;
- if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
+ if (__copy_from_user(&cset.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
goto badframe;
+ sigset32_to_sigset(cset.sig, set.sig);
set_current_blocked(&set);
if (restore_sigregs32(regs, &frame->sregs))
goto badframe;
@@ -323,10 +338,12 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = task_pt_regs(current);
rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
+ compat_sigset_t cset;
sigset_t set;
- if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ if (__copy_from_user(&cset, &frame->uc.uc_sigmask, sizeof(cset)))
goto badframe;
+ sigset32_to_sigset(cset.sig, set.sig);
set_current_blocked(&set);
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
@@ -397,7 +414,7 @@ static int setup_frame32(struct ksignal
return -EFAULT;
/* Create struct sigcontext32 on the signal stack */
- memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32);
+ sigset_to_sigset32(set->sig, sc.oldmask);
sc.sregs = (__u32)(unsigned long __force) &frame->sregs;
if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
return -EFAULT;
@@ -458,6 +475,7 @@ static int setup_frame32(struct ksignal
static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
+ compat_sigset_t cset;
rt_sigframe32 __user *frame;
unsigned long restorer;
size_t frame_size;
@@ -505,11 +523,12 @@ static int setup_rt_frame32(struct ksign
store_sigregs();
/* Create ucontext on the signal stack. */
+ sigset_to_sigset32(set->sig, cset.sig);
if (__put_user(uc_flags, &frame->uc.uc_flags) ||
__put_user(0, &frame->uc.uc_link) ||
__compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
save_sigregs32(regs, &frame->uc.uc_mcontext) ||
- __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
+ __copy_to_user(&frame->uc.uc_sigmask, &cset, sizeof(cset)) ||
save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
return -EFAULT;
--
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