linux-kernel - [PATCH 2/3] pidns: kill the unnecessary CLONE_NEWPID in copy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130822171001.GA20321@redhat.com>
Date:	Thu, 22 Aug 2013 19:10:01 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Andy Lutomirski <luto@...capital.net>,
	Brad Spengler <spender@...ecurity.net>,
	Colin Walters <walters@...hat.com>,
	Pavel Emelyanov <xemul@...allels.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] pidns: kill the unnecessary CLONE_NEWPID in
	copy_process()

8382fcac "pidns: Outlaw thread creation after unshare(CLONE_NEWPID)"
nacks CLONE_NEWPID if the forking process unshared pid_ns. This is
correct but unnecessary, copy_pid_ns() does the same check.

Test-case (needs root or CLONE_NEWUSER should be added):

	static int child(void *arg)
	{
		return 0;
	}

	static char stack[16 * 1024];

	int main(void)
	{
		pid_t pid;

		assert(unshare(CLONE_NEWPID) == 0);

		pid = clone(child, stack + sizeof(stack) / 2,
				CLONE_NEWPID | SIGCHLD, NULL);
		assert(pid < 0 && errno == EINVAL);

		return 0;
	}

clone(CLONE_NEWPID) correctly fails with or without this change.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 kernel/fork.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 86f5376..8d56338 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1176,7 +1176,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	 * If the new process will be in a different pid namespace don't
 	 * allow the creation of threads, or share the signal handlers.
 	 */
-	if ((clone_flags & (CLONE_SIGHAND | CLONE_NEWPID)) &&
+	if ((clone_flags & CLONE_SIGHAND) &&
 	    (task_active_pid_ns(current) != current->nsproxy->pid_ns))
 		return ERR_PTR(-EINVAL);
 
-- 
1.5.5.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/