Re: [Y2038] [PATCH 20/23] y2038: move itimer reset into itimer.c

On Fri, Nov 8, 2019 at 10:18 PM Arnd Bergmann arnd@arndb.de wrote:

Preparing for a change to the itimer internals, stop using the do_setitimer() symbol and instead use a new higher-level interface.

The do_getitimer()/do_setitimer functions can now be made static, allowing the compiler to potentially produce better object code.

Signed-off-by: Arnd Bergmann arnd@arndb.de

include/linux/time.h | 9 +++++---- kernel/time/itimer.c | 15 +++++++++++++-- security/selinux/hooks.c | 10 +++------- 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/include/linux/time.h b/include/linux/time.h index 27d83fd2ae61..0760a4f5a15c 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -35,10 +35,11 @@ extern time64_t mktime64(const unsigned int year, const unsigned int mon, extern u32 (*arch_gettimeoffset)(void); #endif

-struct itimerval; -extern int do_setitimer(int which, struct itimerval *value,

•                   struct itimerval *ovalue);
  

-extern int do_getitimer(int which, struct itimerval *value); +#ifdef CONFIG_POSIX_TIMERS +extern void clear_itimer(void); +#else +static inline void clear_itimer(void) {} +#endif

extern long do_utimes(int dfd, const char __user *filename, struct timespec64 *times, int flags);

diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index 4664c6addf69..ce9cd19ce72e 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -73,7 +73,7 @@ static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, value->it_interval = ns_to_timeval(interval); }

-int do_getitimer(int which, struct itimerval *value) +static int do_getitimer(int which, struct itimerval *value) { struct task_struct *tsk = current;

@@ -197,7 +197,7 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, #define timeval_valid(t) \ (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))

-int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) +static int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) { struct task_struct *tsk = current; struct hrtimer *timer; @@ -249,6 +249,17 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) return 0; }

+#ifdef CONFIG_SECURITY_SELINUX

Did you mean "#ifdef CONFIG_POSIX_TIMERS" here to match the header?

+void clear_itimer(void) +{

•   struct itimerval v = {};
  

•   int i;
  

•   for (i = 0; i < 3; i++)
  

•           do_setitimer(i, &v, NULL);
  

+} +#endif

#ifdef __ARCH_WANT_SYS_ALARM

/** diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9625b99e677f..c3f2e89acb87 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2549,9 +2549,8 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm) static void selinux_bprm_committed_creds(struct linux_binprm *bprm) { const struct task_security_struct *tsec = selinux_cred(current_cred());

•   struct itimerval itimer;
    u32 osid, sid;
  

•   int rc, i;
  

•   int rc;
  
    osid = tsec->osid;
    sid = tsec->sid;
  

@@ -2569,11 +2568,8 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm) rc = avc_has_perm(&selinux_state, osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL); if (rc) {

•           if (IS_ENABLED(CONFIG_POSIX_TIMERS)) {
  

•                   memset(&itimer, 0, sizeof itimer);
  

•                   for (i = 0; i < 3; i++)
  

•                           do_setitimer(i, &itimer, NULL);
  

•           }
  

•           if (IS_ENABLED(CONFIG_POSIX_TIMERS))
  

•                   clear_itimer();
  

Since you already define a no-op fallback for the case of !IS_ENABLED(CONFIG_POSIX_TIMERS) in time.h, why not simply call clear_itimer() unconditionally?

            spin_lock_irq(&current->sighand->siglock);
            if (!fatal_signal_pending(current)) {
                    flush_sigqueue(&current->pending);

-- 2.20.0