3.2.72-rc1 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>
[bwh: Backported to 3.2:
- Introduce local compat_sigset_t in setup_frame32()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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
@@ -52,6 +52,19 @@ typedef struct
__u32 gprs_high[NUM_GPRS];
} 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, siginfo_t *from)
{
int err;
@@ -361,12 +374,14 @@ asmlinkage long sys32_sigreturn(void)
{
struct pt_regs *regs = task_pt_regs(current);
sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
+ compat_sigset_t cset;
sigset_t set;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
- 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);
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (restore_sigregs32(regs, &frame->sregs))
@@ -383,6 +398,7 @@ asmlinkage long sys32_rt_sigreturn(void)
{
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;
stack_t st;
__u32 ss_sp;
@@ -391,8 +407,9 @@ asmlinkage long sys32_rt_sigreturn(void)
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
- 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);
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
@@ -464,13 +481,16 @@ static int setup_frame32(int sig, struct
sigset_t *set, struct pt_regs * regs)
{
sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(sigframe32));
+ compat_sigset_t cset;
+
if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe32)))
goto give_sigsegv;
if (frame == (void __user *) -1UL)
goto give_sigsegv;
- if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32))
+ sigset_to_sigset32(set->sig, cset.sig);
+ if (__copy_to_user(&frame->sc.oldmask, &cset.sig, _SIGMASK_COPY_SIZE32))
goto give_sigsegv;
if (save_sigregs32(regs, &frame->sregs))
@@ -524,6 +544,7 @@ give_sigsegv:
static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs * regs)
{
+ compat_sigset_t cset;
int err = 0;
rt_sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(rt_sigframe32));
if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe32)))
@@ -536,6 +557,7 @@ static int setup_rt_frame32(int sig, str
goto give_sigsegv;
/* Create the ucontext. */
+ sigset_to_sigset32(set->sig, cset.sig);
err |= __put_user(UC_EXTENDED, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
@@ -544,7 +566,7 @@ static int setup_rt_frame32(int sig, str
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= save_sigregs32(regs, &frame->uc.uc_mcontext);
err |= save_sigregs_gprs_high(regs, frame->gprs_high);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ err |= __copy_to_user(&frame->uc.uc_sigmask, &cset, sizeof(cset));
if (err)
goto give_sigsegv;
--
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