Oren Laadan [[email protected]] wrote:
|
|
| Sukadev Bhattiprolu wrote:
| >
| > Subject: [RFC][v8][PATCH 7/10]: Check invalid clone flags
| >
| > As pointed out by Oren Laadan, we want to ensure that unused bits in the
| > clone-flags remain unused and available for future. To ensure this, define
| > a mask of clone-flags and check the flags in the clone() system calls.
| >
| > Changelog[v8]:
| > - New patch in set
| >
| > Signed-off-by: Sukadev Bhattiprolu <[email protected]>
| >
| > ---
| > include/linux/sched.h | 10 ++++++++++
| > kernel/fork.c | 3 +++
| > 2 files changed, 13 insertions(+)
| >
| > Index: linux-2.6/include/linux/sched.h
| > ===================================================================
| > --- linux-2.6.orig/include/linux/sched.h 2009-10-02 18:53:55.000000000
-0700
| > +++ linux-2.6/include/linux/sched.h 2009-10-02 19:58:21.000000000 -0700
| > @@ -29,6 +29,16 @@
| > #define CLONE_NEWNET 0x40000000 /* New network
namespace */
| > #define CLONE_IO 0x80000000 /* Clone io context */
| >
| > +#define VALID_CLONE_FLAGS (CSIGNAL | CLONE_VM | CLONE_FS | CLONE_FILES |\
| > + CLONE_SIGHAND | CLONE_PTRACE | CLONE_VFORK |\
| > + CLONE_PARENT | CLONE_THREAD | CLONE_NEWNS |\
| > + CLONE_SYSVSEM | CLONE_SETTLS |\
| > + CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID |\
| > + CLONE_DETACHED | CLONE_UNTRACED |\
| > + CLONE_CHILD_SETTID | CLONE_STOPPED |\
| > + CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER |\
| > + CLONE_NEWPID | CLONE_NEWNET| CLONE_IO)
| > +
| > /*
| > * Scheduling policies
| > */
| > Index: linux-2.6/kernel/fork.c
| > ===================================================================
| > --- linux-2.6.orig/kernel/fork.c 2009-10-02 19:00:08.000000000 -0700
| > +++ linux-2.6/kernel/fork.c 2009-10-02 19:57:36.000000000 -0700
| > @@ -942,6 +942,9 @@ static struct task_struct *copy_process(
| > struct task_struct *p;
| > int cgroup_callbacks_done = 0;
| >
|
| We can safely apply these tests to clone3(), because it is a new syscall.
|
| However, I don't know if applying it to clone() can break existing
| application that may already be (incorrectly) using invalid flags ?
Doing the check in copy_process() seems would apply to all architectures.
As for breaking an existing app, there is only one unused flag, 0x00001000
(bw CLONE_SIGHAND and CLONE_PTRACE). If an application could be using that
and we don't want to break it, maybe we can add following macro to the
VALID_CLONE_FLAGS list ?
#define CLONE_UNUSED_BIT 0x00001000
--
To unsubscribe from this list: send the line "unsubscribe linux-api" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
