[Y2038] [PATCH v2 3/5] ppoll: use __kernel_timespec

struct timespec is not y2038 safe. struct __kernel_timespec is the new y2038 safe structure for all syscalls that are using struct timespec. Update ppoll 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_ppoll Compat : compat_sys_ppoll_time64

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

Native 32 bit : ppoll_time32 Compat : compat_sys_ppoll

Signed-off-by: Deepa Dinamani deepa.kernel@gmail.com --- fs/select.c | 169 ++++++++++++++++++++++++++------------- include/linux/compat.h | 5 ++ include/linux/syscalls.h | 5 +- 3 files changed, 123 insertions(+), 56 deletions(-)

diff --git a/fs/select.c b/fs/select.c index eb9132520197..f3beef5e0eea 100644 --- a/fs/select.c +++ b/fs/select.c @@ -287,12 +287,18 @@ int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec) return 0; }

+enum poll_time_type { + PT_TIMEVAL = 0, + PT_OLD_TIMEVAL = 1, + PT_TIMESPEC = 2, + PT_OLD_TIMESPEC = 3, +}; + static int poll_select_copy_remaining(struct timespec64 *end_time, void __user *p, - int timeval, int ret) + enum poll_time_type pt_type, int ret) { struct timespec64 rts; - struct timeval rtv;

if (!p) return ret; @@ -310,18 +316,40 @@ static int poll_select_copy_remaining(struct timespec64 *end_time, rts.tv_sec = rts.tv_nsec = 0;

- if (timeval) { - if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec)) - memset(&rtv, 0, sizeof(rtv)); - rtv.tv_sec = rts.tv_sec; - rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; + switch (pt_type) { + case PT_TIMEVAL: + { + struct timeval rtv;

- if (!copy_to_user(p, &rtv, sizeof(rtv))) + if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec)) + memset(&rtv, 0, sizeof(rtv)); + rtv.tv_sec = rts.tv_sec; + rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; + if (!copy_to_user(p, &rtv, sizeof(rtv))) + return ret; + } + break; + case PT_OLD_TIMEVAL: + { + struct old_timeval32 rtv; + + rtv.tv_sec = rts.tv_sec; + rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; + if (!copy_to_user(p, &rtv, sizeof(rtv))) + return ret; + } + break; + case PT_TIMESPEC: + if (!put_timespec64(&rts, p)) return ret; - - } else if (!put_timespec64(&rts, p)) - return ret; - + break; + case PT_OLD_TIMESPEC: + if (!put_old_timespec32(&rts, p)) + return ret; + break; + default: + BUG(); + } /* * If an application puts its timeval in read-only memory, we * don't want the Linux-specific update to the timeval to @@ -689,7 +717,7 @@ static int kern_select(int n, fd_set __user *inp, fd_set __user *outp, }

ret = core_sys_select(n, inp, outp, exp, to); - ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); + ret = poll_select_copy_remaining(&end_time, tvp, PT_TIMEVAL, ret);

return ret; } @@ -722,7 +750,7 @@ 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, 0, ret); + ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);

restore_user_sigmask(sigmask, &sigsaved);

@@ -1026,7 +1054,7 @@ SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, }

SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, - struct timespec __user *, tsp, const sigset_t __user *, sigmask, + struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask, size_t, sigsetsize) { sigset_t ksigmask, sigsaved; @@ -1054,60 +1082,50 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, if (ret == -EINTR) ret = -ERESTARTNOHAND;

- ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); + ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);

return ret; }

-#ifdef CONFIG_COMPAT -#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t)) +#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)

-static -int compat_poll_select_copy_remaining(struct timespec64 *end_time, void __user *p, - int timeval, int ret) +SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds, + struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask, + size_t, sigsetsize) { - struct timespec64 ts; + sigset_t ksigmask, sigsaved; + struct timespec64 ts, end_time, *to = NULL; + int ret;

- if (!p) - return ret; + if (tsp) { + if (get_old_timespec32(&ts, tsp)) + return -EFAULT;

- if (current->personality & STICKY_TIMEOUTS) - goto sticky; + to = &end_time; + if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) + return -EINVAL; + }

- /* No update for zero timeout */ - if (!end_time->tv_sec && !end_time->tv_nsec) + ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (ret) return ret;

- ktime_get_ts64(&ts); - ts = timespec64_sub(*end_time, ts); - if (ts.tv_sec < 0) - ts.tv_sec = ts.tv_nsec = 0; + ret = do_sys_poll(ufds, nfds, to);

- if (timeval) { - struct old_timeval32 rtv; + restore_user_sigmask(sigmask, &sigsaved);

- rtv.tv_sec = ts.tv_sec; - rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC; + /* We can restart this syscall, usually */ + if (ret == -EINTR) + ret = -ERESTARTNOHAND;

- if (!copy_to_user(p, &rtv, sizeof(rtv))) - return ret; - } else { - if (!put_old_timespec32(&ts, p)) - return ret; - } - /* - * If an application puts its timeval in read-only memory, we - * don't want the Linux-specific update to the timeval to - * cause a fault after the select has completed - * successfully. However, because we're not updating the - * timeval, we can't restart the system call. - */ + ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);

-sticky: - if (ret == -ERESTARTNOHAND) - ret = -EINTR; return ret; } +#endif + +#ifdef CONFIG_COMPAT +#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))

/* * Ooo, nasty. We need here to frob 32-bit unsigned longs to @@ -1239,7 +1257,7 @@ static int do_compat_select(int n, compat_ulong_t __user *inp, }

ret = compat_core_sys_select(n, inp, outp, exp, to); - ret = compat_poll_select_copy_remaining(&end_time, tvp, 1, ret); + ret = poll_select_copy_remaining(&end_time, tvp, PT_OLD_TIMEVAL, ret);

return ret; } @@ -1292,7 +1310,7 @@ 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 = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); + ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);

restore_user_sigmask(sigmask, &sigsaved);

@@ -1318,6 +1336,7 @@ COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp, sigsetsize); }

+#if defined(CONFIG_COMPAT_32BIT_TIME) COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, struct old_timespec32 __user *, tsp, const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) @@ -1347,8 +1366,48 @@ COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, if (ret == -EINTR) ret = -ERESTARTNOHAND;

- ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); + ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret); + + return ret; +} +#endif + +/* New compat syscall for 64 bit time_t*/ +#if defined(CONFIG_64BIT_TIME) + +COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds, + unsigned int, nfds, struct __kernel_timespec __user *, tsp, + const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) +{ + sigset_t ksigmask, sigsaved; + struct timespec64 ts, end_time, *to = NULL; + int ret; + + if (tsp) { + if (get_timespec64(&ts, tsp)) + return -EFAULT; + + to = &end_time; + if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) + return -EINVAL; + } + + ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize); + if (ret) + return ret; + + ret = do_sys_poll(ufds, nfds, to); + + restore_user_sigmask(sigmask, &sigsaved); + + /* We can restart this syscall, usually */ + if (ret == -EINTR) + ret = -ERESTARTNOHAND; + + ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);

return ret; } + +#endif #endif diff --git a/include/linux/compat.h b/include/linux/compat.h index 03d65c509eeb..349a2d98e450 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -646,6 +646,11 @@ asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds, struct old_timespec32 __user *tsp, const compat_sigset_t __user *sigmask, compat_size_t sigsetsize); +asmlinkage long compat_sys_ppoll_time64(struct pollfd __user *ufds, + unsigned int nfds, + struct __kernel_timespec __user *tsp, + const compat_sigset_t __user *sigmask, + compat_size_t sigsetsize);

/* fs/signalfd.c */ asmlinkage long compat_sys_signalfd4(int ufd, diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 82682b69435e..9755e70cfbb0 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -470,7 +470,10 @@ asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *, fd_set __user *, struct timespec __user *, void __user *); asmlinkage long sys_ppoll(struct pollfd __user *, unsigned int, - struct timespec __user *, const sigset_t __user *, + struct __kernel_timespec __user *, const sigset_t __user *, + size_t); +asmlinkage long sys_ppoll_time32(struct pollfd __user *, unsigned int, + struct old_timespec32 __user *, const sigset_t __user *, size_t);

/* fs/signalfd.c */