On Thu, Oct 13, 2005 at 12:50:03AM +0200, Moritz Muehlenhoff wrote:
> Hi,
> on linux-kernel there were some iterations of patch review before an
> acceptable patch could be cooked up. Here's the final one from Harald
> Welte. Meanwhile Linus already commited an older version version of
> his patch, for which Harald wanted to push an additional patch, so
> I guess it's the best to directly include this fix.
Sorry this is taking a while to get in.
I had do do a bit of backporting (attached for reference).
And I am begining to suspect that it is an ABI breaker.
Ohh, and I think I separately broke the 2.6.8 build, so I am looking
into that.
--
Horms
--- from-0001/drivers/usb/core/devio.c
+++ to-0003/drivers/usb/core/devio.c 2005-10-14 16:50:10.000000000 +0900
@@ -30,6 +30,8 @@
* Revision history
* 22.12.1999 0.1 Initial release (split from proc_usb.c)
* 04.01.2000 0.2 Turned into its own filesystem
+ * 30.09.2005 0.3 Fix user-triggerable oops in async URB delivery
+ * (CAN-2005-3055)
*/
/*****************************************************************************/
@@ -53,7 +55,8 @@
struct async {
struct list_head asynclist;
struct dev_state *ps;
- struct task_struct *task;
+ pid_t pid;
+ uid_t uid, euid;
unsigned int signr;
unsigned int ifnum;
void __user *userbuffer;
@@ -270,7 +273,8 @@ static void async_completed(struct urb *
sinfo.si_errno = as->urb->status;
sinfo.si_code = SI_ASYNCIO;
sinfo.si_addr = as->userurb;
- send_sig_info(as->signr, &sinfo, as->task);
+ kill_proc_info_as_uid(as->signr, &sinfo, as->pid, as->uid,
+ as->euid);
}
wake_up(&ps->wait);
}
@@ -495,9 +499,11 @@ static int usbdev_open(struct inode *ino
INIT_LIST_HEAD(&ps->async_pending);
INIT_LIST_HEAD(&ps->async_completed);
init_waitqueue_head(&ps->wait);
- ps->discsignr = 0;
- ps->disctask = current;
- ps->disccontext = NULL;
+ ps->disc.signr = 0;
+ ps->disc.pid = current->pid;
+ ps->disc.uid = current->uid;
+ ps->disc.euid = current->euid;
+ ps->disc.context = NULL;
ps->ifclaimed = 0;
wmb();
list_add_tail(&ps->list, &dev->filelist);
@@ -940,7 +946,9 @@ static int proc_submiturb(struct dev_sta
as->userbuffer = NULL;
as->signr = uurb.signr;
as->ifnum = ifnum;
- as->task = current;
+ as->pid = current->pid;
+ as->uid = current->uid;
+ as->euid = current->euid;
if (!(uurb.endpoint & USB_DIR_IN)) {
if (copy_from_user(as->urb->transfer_buffer, uurb.buffer,
as->urb->transfer_buffer_length)) {
free_async(as);
@@ -1059,8 +1067,8 @@ static int proc_disconnectsignal(struct
return -EFAULT;
if (ds.signr != 0 && (ds.signr < SIGRTMIN || ds.signr > SIGRTMAX))
return -EINVAL;
- ps->discsignr = ds.signr;
- ps->disccontext = ds.context;
+ ps->disc.signr = ds.signr;
+ ps->disc.context = ds.context;
return 0;
}
--- from-0001/drivers/usb/core/inode.c
+++ to-0003/drivers/usb/core/inode.c 2005-10-14 16:46:34.000000000 +0900
@@ -815,12 +815,14 @@ void usbfs_remove_device(struct usb_devi
while (!list_empty(&dev->filelist)) {
ds = list_entry(dev->filelist.next, struct dev_state, list);
list_del_init(&ds->list);
- if (ds->discsignr) {
+ if (ds->disc.signr) {
sinfo.si_signo = SIGPIPE;
sinfo.si_errno = EPIPE;
sinfo.si_code = SI_ASYNCIO;
- sinfo.si_addr = ds->disccontext;
- send_sig_info(ds->discsignr, &sinfo, ds->disctask);
+ sinfo.si_addr = ds->disc.context;
+ kill_proc_info_as_uid(ds->disc.signr, &sinfo,
+ ds->disc.pid, ds->disc.uid,
+ ds->disc.euid);
}
}
usbfs_update_special();
--- from-0001/include/linux/sched.h
+++ to-0003/include/linux/sched.h 2005-10-14 16:58:21.000000000 +0900
@@ -794,6 +794,7 @@ extern int __kill_pg_info(int sig, struc
extern int kill_pg_info(int, struct siginfo *, pid_t);
extern int kill_sl_info(int, struct siginfo *, pid_t);
extern int kill_proc_info(int, struct siginfo *, pid_t);
+extern int kill_proc_info_as_uid(int, struct siginfo *, pid_t, uid_t, uid_t);
extern void notify_parent(struct task_struct *, int);
extern void do_notify_parent(struct task_struct *, int);
extern void force_sig(int, struct task_struct *);
--- from-0001/include/linux/usbdevice_fs.h
+++ to-0003/include/linux/usbdevice_fs.h 2005-10-14 16:53:51.000000000
+0900
@@ -160,9 +160,12 @@ struct dev_state {
struct list_head async_pending;
struct list_head async_completed;
wait_queue_head_t wait; /* wake up if a request completed */
- unsigned int discsignr;
- struct task_struct *disctask;
- void __user *disccontext;
+ struct {
+ unsigned int signr;
+ pid_t pid;
+ uid_t uid, euid;
+ void __user *context;
+ } disc;
unsigned long ifclaimed;
};
--- from-0001/kernel/signal.c
+++ to-0003/kernel/signal.c 2005-10-14 16:57:03.000000000 +0900
@@ -1154,6 +1154,42 @@ kill_proc_info(int sig, struct siginfo *
return error;
}
+/* This is like kill_proc_info(), but doesn't use uid/euid of "current".
+ * Most likely this function is not what you want, it was added as a special
+ * case for usbdevio */
+int
+kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
+ uid_t uid, uid_t euid)
+{
+ int ret = -EINVAL;
+ struct task_struct *p;
+
+ if (!valid_signal(sig))
+ return ret;
+
+ read_lock(&tasklist_lock);
+ p = find_task_by_pid(pid);
+ if (!p) {
+ ret = -ESRCH;
+ goto out_unlock;
+ }
+ if ((!info || ((unsigned long)info != 1 &&
+ (unsigned long)info != 2 && SI_FROMUSER(info)))
+ && (euid ^ p->suid) && (euid ^ p->uid)
+ && (uid ^ p->suid) && (uid ^ p->uid)) {
+ ret = -EPERM;
+ goto out_unlock;
+ }
+ if (sig && p->sighand) {
+ unsigned long flags;
+ spin_lock_irqsave(&p->sighand->siglock, flags);
+ ret = __group_send_sig_info(sig, info, p);
+ spin_unlock_irqrestore(&p->sighand->siglock, flags);
+ }
+out_unlock:
+ read_unlock(&tasklist_lock);
+ return ret;
+}
/*
* kill_something_info() interprets pid in interesting ways just like kill(2).
@@ -1892,6 +1928,7 @@ EXPORT_SYMBOL(kill_pg);
EXPORT_SYMBOL(kill_pg_info);
EXPORT_SYMBOL(kill_proc);
EXPORT_SYMBOL(kill_proc_info);
+EXPORT_SYMBOL_GPL(kill_proc_info_as_uid);
EXPORT_SYMBOL(kill_sl);
EXPORT_SYMBOL(kill_sl_info);
EXPORT_SYMBOL(notify_parent);
