From 83f62a2eacb1d6945c78523f20e0c34b5d94913c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov 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 Acked-by: KOSAKI Motohiro Cc: Al Viro Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index 9cbad5b0187e..81ae6212187a 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++; }