From 359566faefa850504d146839d74496f0cf12d3b9 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 14 May 2017 20:39:39 -0400 Subject: [PATCH] kernel_wait4()/kernel_waitid(): delay copying status to userland Signed-off-by: Al Viro --- kernel/exit.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index d44f12948c5f..94cdccf8e7e7 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1002,7 +1002,7 @@ struct wait_opts { struct pid *wo_pid; struct siginfo __user *wo_info; - int __user *wo_stat; + int wo_stat; struct rusage *wo_rusage; wait_queue_t child_wait; @@ -1189,8 +1189,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) retval = 0; status = (p->signal->flags & SIGNAL_GROUP_EXIT) ? p->signal->group_exit_code : p->exit_code; - if (!retval && wo->wo_stat) - retval = put_user(status, wo->wo_stat); + wo->wo_stat = status; infop = wo->wo_info; if (!retval && infop) @@ -1322,8 +1321,7 @@ unlock_sig: if (wo->wo_rusage) getrusage(p, RUSAGE_BOTH, wo->wo_rusage); retval = 0; - if (!retval && wo->wo_stat) - retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat); + wo->wo_stat = (exit_code << 8) | 0x7f; infop = wo->wo_info; if (!retval && infop) @@ -1383,12 +1381,9 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p) if (!wo->wo_info) { if (wo->wo_rusage) getrusage(p, RUSAGE_BOTH, wo->wo_rusage); - retval = 0; put_task_struct(p); - if (!retval && wo->wo_stat) - retval = put_user(0xffff, wo->wo_stat); - if (!retval) - retval = pid; + wo->wo_stat = 0xffff; + retval = pid; } else { retval = wait_noreap_copyout(wo, p, pid, uid, CLD_CONTINUED, SIGCONT); @@ -1662,7 +1657,6 @@ static long kernel_waitid(int which, pid_t upid, struct siginfo __user *infop, wo.wo_pid = pid; wo.wo_flags = options; wo.wo_info = infop; - wo.wo_stat = NULL; wo.wo_rusage = ru; ret = do_wait(&wo); @@ -1734,10 +1728,12 @@ static long kernel_wait4(pid_t upid, int __user *stat_addr, wo.wo_pid = pid; wo.wo_flags = options | WEXITED; wo.wo_info = NULL; - wo.wo_stat = stat_addr; + wo.wo_stat = 0; wo.wo_rusage = ru; ret = do_wait(&wo); put_pid(pid); + if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr)) + ret = -EFAULT; return ret; } -- 2.20.1