[PATCH v4 4/5] pselect6: use __kernel_timespec

From: Deepa Dinamani
Date: Thu Sep 20 2018 - 00:53:12 EST


struct timespec is not y2038 safe.
struct __kernel_timespec is the new y2038 safe structure for all
syscalls that are using struct timespec.
Update pselect interfaces to use struct __kernel_timespec.

sigset_t also has different representations on 32 bit and 64 bit
architectures. Hence, we need to support the following different
syscalls:

New y2038 safe syscalls:
(Controlled by CONFIG_64BIT_TIME for 32 bit ABIs)

Native 64 bit(unchanged) and native 32 bit : sys_pselect6
Compat : compat_sys_pselect6_time64

Older y2038 unsafe syscalls:
(Controlled by CONFIG_32BIT_COMPAT_TIME for 32 bit ABIs)

Native 32 bit : pselect6_time32
Compat : compat_sys_pselect6

Note that all other versions of select syscalls will not have
y2038 safe versions.

Signed-off-by: Deepa Dinamani <deepa.kernel@xxxxxxxxx>
---
fs/select.c | 94 ++++++++++++++++++++++++++++++++++------
include/linux/compat.h | 5 +++
include/linux/syscalls.h | 5 ++-
3 files changed, 90 insertions(+), 14 deletions(-)

diff --git a/fs/select.c b/fs/select.c
index d332be059487..4c8652390c94 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -729,16 +729,27 @@ SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
}

static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
- fd_set __user *exp, struct timespec __user *tsp,
- const sigset_t __user *sigmask, size_t sigsetsize)
+ fd_set __user *exp, void __user *tsp,
+ const sigset_t __user *sigmask, size_t sigsetsize,
+ enum poll_time_type type)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;

if (tsp) {
- if (get_timespec64(&ts, tsp))
- return -EFAULT;
+ switch (type) {
+ case PT_TIMESPEC:
+ if (get_timespec64(&ts, tsp))
+ return -EFAULT;
+ break;
+ case PT_OLD_TIMESPEC:
+ if (get_old_timespec32(&ts, tsp))
+ return -EFAULT;
+ break;
+ default:
+ BUG();
+ }

to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
@@ -750,7 +761,7 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
return ret;

ret = core_sys_select(n, inp, outp, exp, to);
- ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
+ ret = poll_select_copy_remaining(&end_time, tsp, type, ret);

restore_user_sigmask(sigmask, &sigsaved);

@@ -764,7 +775,27 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
* the sigset size.
*/
SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
- fd_set __user *, exp, struct timespec __user *, tsp,
+ fd_set __user *, exp, struct __kernel_timespec __user *, tsp,
+ void __user *, sig)
+{
+ size_t sigsetsize = 0;
+ sigset_t __user *up = NULL;
+
+ if (sig) {
+ if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
+ || __get_user(up, (sigset_t __user * __user *)sig)
+ || __get_user(sigsetsize,
+ (size_t __user *)(sig+sizeof(void *))))
+ return -EFAULT;
+ }
+
+ return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_TIMESPEC);
+}
+
+#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
+
+SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *, outp,
+ fd_set __user *, exp, struct old_timespec32 __user *, tsp,
void __user *, sig)
{
size_t sigsetsize = 0;
@@ -778,9 +809,11 @@ SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
return -EFAULT;
}

- return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
+ return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_OLD_TIMESPEC);
}

+#endif
+
#ifdef __ARCH_WANT_SYS_OLD_SELECT
struct sel_arg_struct {
unsigned long n;
@@ -1289,16 +1322,26 @@ COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)

static long do_compat_pselect(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
- struct old_timespec32 __user *tsp, compat_sigset_t __user *sigmask,
- compat_size_t sigsetsize)
+ void __user *tsp, compat_sigset_t __user *sigmask,
+ compat_size_t sigsetsize, enum poll_time_type type)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;

if (tsp) {
- if (get_old_timespec32(&ts, tsp))
- return -EFAULT;
+ switch (type) {
+ case PT_OLD_TIMESPEC:
+ if (get_old_timespec32(&ts, tsp))
+ return -EFAULT;
+ break;
+ case PT_TIMESPEC:
+ if (get_timespec64(&ts, tsp))
+ return -EFAULT;
+ break;
+ default:
+ BUG();
+ }

to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
@@ -1310,13 +1353,35 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp,
return ret;

ret = compat_core_sys_select(n, inp, outp, exp, to);
- ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
+ ret = poll_select_copy_remaining(&end_time, tsp, type, ret);

restore_user_sigmask(sigmask, &sigsaved);

return ret;
}

+COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp,
+ compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
+ struct __kernel_timespec __user *, tsp, void __user *, sig)
+{
+ compat_size_t sigsetsize = 0;
+ compat_uptr_t up = 0;
+
+ if (sig) {
+ if (!access_ok(VERIFY_READ, sig,
+ sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
+ __get_user(up, (compat_uptr_t __user *)sig) ||
+ __get_user(sigsetsize,
+ (compat_size_t __user *)(sig+sizeof(up))))
+ return -EFAULT;
+ }
+
+ return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
+ sigsetsize, PT_TIMESPEC);
+}
+
+#if defined(CONFIG_COMPAT_32BIT_TIME)
+
COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct old_timespec32 __user *, tsp, void __user *, sig)
@@ -1332,10 +1397,13 @@ COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp,
(compat_size_t __user *)(sig+sizeof(up))))
return -EFAULT;
}
+
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
- sigsetsize);
+ sigsetsize, PT_OLD_TIMESPEC);
}

+#endif
+
#if defined(CONFIG_COMPAT_32BIT_TIME)
COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds,
unsigned int, nfds, struct old_timespec32 __user *, tsp,
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 349a2d98e450..6896e6e51c00 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -641,6 +641,11 @@ asmlinkage long compat_sys_pselect6(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *exp,
struct old_timespec32 __user *tsp,
void __user *sig);
+asmlinkage long compat_sys_pselect6_time64(int n, compat_ulong_t __user *inp,
+ compat_ulong_t __user *outp,
+ compat_ulong_t __user *exp,
+ struct __kernel_timespec __user *tsp,
+ void __user *sig);
asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds,
unsigned int nfds,
struct old_timespec32 __user *tsp,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 9755e70cfbb0..e9cd0409c3fe 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -467,7 +467,10 @@ asmlinkage long sys_sendfile64(int out_fd, int in_fd,

/* fs/select.c */
asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *,
- fd_set __user *, struct timespec __user *,
+ fd_set __user *, struct __kernel_timespec __user *,
+ void __user *);
+asmlinkage long sys_pselect6_time32(int, fd_set __user *, fd_set __user *,
+ fd_set __user *, struct old_timespec32 __user *,
void __user *);
asmlinkage long sys_ppoll(struct pollfd __user *, unsigned int,
struct __kernel_timespec __user *, const sigset_t __user *,
--
2.17.1