From 83f62a2eacb1d6945c78523f20e0c34b5d94913c Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Thu, 23 Jan 2014 15:55:49 -0800
Subject: [PATCH] exec:check_unsafe_exec: use while_each_thread() rather than
next_thread()
next_thread() should be avoided, change check_unsafe_exec() to use
while_each_thread().
Nobody except signal->curr_target actually needs next_thread-like code,
and we need to change (fix) this interface. This particular code is fine,
p == current. But in general the code like this can loop forever if p
exits and next_thread(t) can't reach the unhashed thread.
This also saves 32 bytes.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/exec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/exec.c b/fs/exec.c
index 9cbad5b0187e0..81ae6212187aa 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1243,10 +1243,11 @@ static int check_unsafe_exec(struct linux_binprm *bprm)
if (current->no_new_privs)
bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
+ t = p;
n_fs = 1;
spin_lock(&p->fs->lock);
rcu_read_lock();
- for (t = next_thread(p); t != p; t = next_thread(t)) {
+ while_each_thread(p, t) {
if (t->fs == p->fs)
n_fs++;
}
--
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