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authorRoland McGrath <roland@redhat.com>2007-05-06 14:50:20 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:12:57 -0700
commit73243284463a761e04d69d22c7516b2be7de096c (patch)
tree1a823a613568b48d3a4db694aa02ce380643a3dc
parent906e0be197232c219197d058ef5095baa7764cd4 (diff)
Return EPERM not ECHILD on security_task_wait failure
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. [jmorris@namei.org: switch error code to EACCES] Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/exit.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index b55ed4cc9104..92369240d91d 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1033,6 +1033,8 @@ asmlinkage void sys_exit_group(int error_code)
static int eligible_child(pid_t pid, int options, struct task_struct *p)
{
+ int err;
+
if (pid > 0) {
if (p->pid != pid)
return 0;
@@ -1066,8 +1068,9 @@ static int eligible_child(pid_t pid, int options, struct task_struct *p)
if (delay_group_leader(p))
return 2;
- if (security_task_wait(p))
- return 0;
+ err = security_task_wait(p);
+ if (err)
+ return err;
return 1;
}
@@ -1449,6 +1452,7 @@ static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
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 +1461,7 @@ 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 +1477,12 @@ repeat:
if (!ret)
continue;
+ if (unlikely(ret < 0)) {
+ denied = ret;
+ continue;
+ }
+ allowed = 1;
+
switch (p->state) {
case TASK_TRACED:
/*
@@ -1570,6 +1581,8 @@ check_continued:
goto repeat;
}
retval = -ECHILD;
+ if (unlikely(denied) && !allowed)
+ retval = denied;
end:
current->state = TASK_RUNNING;
remove_wait_queue(&current->signal->wait_chldexit,&wait);

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