+ return-eperm-not-echild-on-security_task_wait-failure.patch added to -mm tree

[akpm]

The patch titled
     Return EPERM not ECHILD on security_task_wait failure
has been added to the -mm tree.  Its filename is
     return-eperm-not-echild-on-security_task_wait-failure.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: Return EPERM not ECHILD on security_task_wait failure
From: Roland McGrath <[EMAIL PROTECTED]>

wait* syscalls return -ECHILD even when an individual PID of a live child
was requested explicitly, when security_task_wait denies the operation. 
This means that something like a broken SELinux policy can produce an
unexpected failure that looks just like a bug with wait or ptrace or
something.

This patch makes do_wait return -EACCES (or other appropriate error returned
from security_task_wait() instead of -ECHILD if some children were ruled out
solely because security_task_wait failed.

Signed-off-by: Roland McGrath <[EMAIL PROTECTED]>
Cc: Stephen Smalley <[EMAIL PROTECTED]>
Cc: Chris Wright <[EMAIL PROTECTED]>
Cc: James Morris <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---

 kernel/exit.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff -puN kernel/exit.c~return-eperm-not-echild-on-security_task_wait-failure 
kernel/exit.c
--- a/kernel/exit.c~return-eperm-not-echild-on-security_task_wait-failure
+++ a/kernel/exit.c
@@ -1067,7 +1067,7 @@ static int eligible_child(pid_t pid, int
                return 2;
 
        if (security_task_wait(p))
-               return 0;
+               return -1;
 
        return 1;
 }
@@ -1449,6 +1449,7 @@ static long do_wait(pid_t pid, int optio
        DECLARE_WAITQUEUE(wait, current);
        struct task_struct *tsk;
        int flag, retval;
+       int allowed, denied;
 
        add_wait_queue(&current->signal->wait_chldexit,&wait);
 repeat:
@@ -1457,6 +1458,7 @@ repeat:
         * match our criteria, even if we are not able to reap it yet.
         */
        flag = 0;
+       allowed = denied = 0;
        current->state = TASK_INTERRUPTIBLE;
        read_lock(&tasklist_lock);
        tsk = current;
@@ -1472,6 +1474,12 @@ repeat:
                        if (!ret)
                                continue;
 
+                       if (unlikely(ret < 0)) {
+                               denied = 1;
+                               continue;
+                       }
+                       allowed = 1;
+
                        switch (p->state) {
                        case TASK_TRACED:
                                /*
@@ -1570,6 +1578,8 @@ check_continued:
                goto repeat;
        }
        retval = -ECHILD;
+       if (unlikely(denied) && !allowed)
+               retval = -EPERM;
 end:
        current->state = TASK_RUNNING;
        remove_wait_queue(&current->signal->wait_chldexit,&wait);
_

Patches currently in -mm which might be from [EMAIL PROTECTED] are

return-eperm-not-echild-on-security_task_wait-failure.patch
return-eperm-not-echild-on-security_task_wait-failure-fix.patch
clone-flag-clone_parent_tidptr-leaves-invalid-results-in-memory.patch
futex-restartable-futex_wait.patch
futex-restartable-futex_wait-fix.patch

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