kernel.git/drivers/net/hamradio/6pack.c, branch linux-4.18.y

drivers, net, hamradio: convert sixpack.refcnt from atomic_t to refcount_t

2017-10-22T01:22:39Z

atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable sixpack.refcnt is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: David S. Miller

net/hamradio/6pack: Convert timers to use timer_setup()

2017-10-18T11:39:37Z

In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: Andreas Koensgen Cc: linux-hams@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: David S. Miller

drivers: net: hamradio: use setup_timer() helper.

2017-09-21T18:44:43Z

Use setup_timer function instead of initializing timer with the function and data fields. Signed-off-by: Allen Pais Signed-off-by: David S. Miller

net: Fix inconsistent teardown and release of private netdev state.

2017-06-07T19:53:24Z

Network devices can allocate reasources and private memory using netdev_ops->ndo_init(). However, the release of these resources can occur in one of two different places. Either netdev_ops->ndo_uninit() or netdev->destructor(). The decision of which operation frees the resources depends upon whether it is necessary for all netdev refs to be released before it is safe to perform the freeing. netdev_ops->ndo_uninit() presumably can occur right after the NETDEV_UNREGISTER notifier completes and the unicast and multicast address lists are flushed. netdev->destructor(), on the other hand, does not run until the netdev references all go away. Further complicating the situation is that netdev->destructor() almost universally does also a free_netdev(). This creates a problem for the logic in register_netdevice(). Because all callers of register_netdevice() manage the freeing of the netdev, and invoke free_netdev(dev) if register_netdevice() fails. If netdev_ops->ndo_init() succeeds, but something else fails inside of register_netdevice(), it does call ndo_ops->ndo_uninit(). But it is not able to invoke netdev->destructor(). This is because netdev->destructor() will do a free_netdev() and then the caller of register_netdevice() will do the same. However, this means that the resources that would normally be released by netdev->destructor() will not be. Over the years drivers have added local hacks to deal with this, by invoking their destructor parts by hand when register_netdevice() fails. Many drivers do not try to deal with this, and instead we have leaks. Let's close this hole by formalizing the distinction between what private things need to be freed up by netdev->destructor() and whether the driver needs unregister_netdevice() to perform the free_netdev(). netdev->priv_destructor() performs all actions to free up the private resources that used to be freed by netdev->destructor(), except for free_netdev(). netdev->needs_free_netdev is a boolean that indicates whether free_netdev() should be done at the end of unregister_netdevice(). Now, register_netdevice() can sanely release all resources after ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit() and netdev->priv_destructor(). And at the end of unregister_netdevice(), we invoke netdev->priv_destructor() and optionally call free_netdev(). Signed-off-by: David S. Miller

Replace with globally

2016-12-24T19:46:01Z

This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*' sed -i -e "s!$PATT!#include !" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro Signed-off-by: Linus Torvalds

6pack: fix buffer length mishandling

2016-09-21T02:51:30Z

Dmitry Vyukov wrote: > different runs). Looking at code, the following looks suspicious -- we > limit copy by 512 bytes, but use the original count which can be > larger than 512: > > static void sixpack_receive_buf(struct tty_struct *tty, > const unsigned char *cp, char *fp, int count) > { > unsigned char buf[512]; > .... > memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); > .... > sixpack_decode(sp, buf, count1); With the sane tty locking we now have I believe the following is safe as we consume the bytes and move them into the decoded buffer before returning. Signed-off-by: Alan Cox Signed-off-by: David S. Miller

6pack: fix free memory scribbles

2016-01-06T06:25:01Z

commit acf673a3187edf72068ee2f92f4dc47d66baed47 fixed a user triggerable free memory scribble but in doing so replaced it with a different one that allows the user to control the data and scribble even more. sixpack_close is called by the tty layer in tty context. The tty context is protected by sp_get() and sp_put(). However network layer activity via sp_xmit() is not protected this way. We must therefore stop the queue otherwise the user gets to dump a buffer mostly of their choice into freed kernel pages. Signed-off-by: Alan Cox Signed-off-by: David S. Miller

6pack: Fix use after free in sixpack_close().

2015-12-18T20:57:33Z

Need to do the unregister_device() after all references to the driver private have been done. Also we need to use del_timer_sync() for the timers so that we don't have any asynchronous references after the unregister. Signed-off-by: David S. Miller

ax25: Stop using magic neighbour cache operations.

2015-03-03T19:44:41Z

Before the ax25 stack calls dev_queue_xmit it always calls ax25_type_trans which sets skb->protocol to ETH_P_AX25. Which means that by looking at the protocol type it is possible to detect IP packets that have not been munged by the ax25 stack in ndo_start_xmit and call a function to munge them. Rename ax25_neigh_xmit to ax25_ip_xmit and tweak the return type and value to be appropriate for an ndo_start_xmit function. Update all of the ax25 devices to test the protocol type for ETH_P_IP and return ax25_ip_xmit as the first thing they do. This preserves the existing semantics of IP packet processing, but the timing will be a little different as the IP packets now pass through the qdisc layer before reaching the ax25 ip packet processing. Remove the now unnecessary ax25 neighbour table operations. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller

ax25: Refactor to use private neighbour operations.

2015-03-02T21:43:40Z

AX25 already has it's own private arp cache operations to isolate it's abuse of dev_rebuild_header to transmit packets. Add a function ax25_neigh_construct that will allow all of the ax25 devices to force using these operations, so that the generic arp code does not need to. Cc: Ralf Baechle Cc: linux-hams@vger.kernel.org Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller