From: Eugene Syromiatnikov <esyr@redhat.com>
To: linux-kernel@vger.kernel.org, Christian Brauner <christian@brauner.io>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>, Tejun Heo <tj@kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Li Zefan <lizefan@huawei.com>,
Peter Zijlstra <peterz@infradead.org>,
cgroups@vger.kernel.org, "Dmitry V. Levin" <ldv@altlinux.org>
Subject: [PATCH] clone3: fix cgroup argument sanity check
Date: Sun, 12 Apr 2020 22:25:33 +0200 [thread overview]
Message-ID: <20200412202533.GA29554@asgard.redhat.com> (raw)
Checking that cgroup field value of struct clone_args is less than 0
is useless, as it is defined as unsigned 64-bit integer. Moreover,
it doesn't catch the situations where its higher bits are lost during
the assignment to the cgroup field of the cgroup field of the internal
struct kernel_clone_args (where it is declared as signed 32-bit
integer), so it is still possible to pass garbage there. A check
against INT_MAX solves both these issues.
Fixes: ef2c41cf38a7559b ("clone3: allow spawning processes into cgroups")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
---
kernel/fork.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 4385f3d..b4f7775 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2631,7 +2631,7 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
!valid_signal(args.exit_signal)))
return -EINVAL;
- if ((args.flags & CLONE_INTO_CGROUP) && args.cgroup < 0)
+ if ((args.flags & CLONE_INTO_CGROUP) && args.cgroup > INT_MAX)
return -EINVAL;
*kargs = (struct kernel_clone_args){
--
2.1.4
next reply other threads:[~2020-04-12 20:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-12 20:25 Eugene Syromiatnikov [this message]
2020-04-12 21:10 ` [PATCH] clone3: fix cgroup argument sanity check Christian Brauner
2020-04-15 12:38 ` Christian Brauner
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