From 6b5f1ddf8fdf04b977a2523a103d03e807fc0471 Mon Sep 17 00:00:00 2001

From: Ryan Sullivan <rysulliv@redhat.com>

Date: Mon, 23 Jan 2023 11:48:28 -0500

Subject: [KPATCH CVE-2022-3564] kpatch fixes for CVE-2022-3564

Kernels:

5.14.0-162.6.1.el9_1

Kpatch-MR: https://gitlab.com/redhat/prdsc/rhel/src/kpatch/rhel-9/-/merge_requests/16

Approved-by: Joe Lawrence (@joe.lawrence)

Approved-by: Yannick Cote (@ycote1)

Changes since last build:

arches: x86_64 ppc64le

l2cap_core.o: changed function: l2cap_rx_state_recv

l2cap_core.o: changed function: l2cap_stream_rx

nfs4proc.o: changed function: nfsd4_copy

nfs4proc.o: changed function: nfsd4_do_async_copy

nft_payload.o: changed function: nft_payload_copy_vlan

sysctl.o: changed function: __do_proc_dointvec

sysctl.o: changed function: __do_proc_douintvec

sysctl.o: changed function: __do_proc_doulongvec_minmax

sysctl.o: changed function: proc_get_long.constprop.0

---------------------------

Modifications: none

commit c4f4f4633ff2000f9f67db4271b8186939690908

Author: Ricardo Robaina <rrobaina@redhat.com>

Date:   Wed Jan 11 14:57:13 2023 -0300

    Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

    Bugzilla: https://bugzilla.redhat.com/2152929

    CVE: CVE-2022-3564

    Y-Commit: 7de3277fe8bf62a5af7d2758f1b13cea20541724

    O-Bugzilla: https://bugzilla.redhat.com/2152931

    O-CVE: CVE-2022-3564

    commit 3aff8aaca4e36dc8b17eaa011684881a80238966

    Author: Maxim Mikityanskiy <maxtram95@gmail.com>

    Date:   Wed Oct 5 00:27:18 2022 +0300

        Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

        Fix the race condition between the following two flows that run in

        parallel:

        1. l2cap_reassemble_sdu -> chan->ops->recv (l2cap_sock_recv_cb) ->

           __sock_queue_rcv_skb.

        2. bt_sock_recvmsg -> skb_recv_datagram, skb_free_datagram.

        An SKB can be queued by the first flow and immediately dequeued and

        freed by the second flow, therefore the callers of l2cap_reassemble_sdu

        can't use the SKB after that function returns. However, some places

        continue accessing struct l2cap_ctrl that resides in the SKB's CB for a

        short time after l2cap_reassemble_sdu returns, leading to a

        use-after-free condition (the stack trace is below, line numbers for

        kernel 5.19.8).

        Fix it by keeping a local copy of struct l2cap_ctrl.

        BUG: KASAN: use-after-free in l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth

        Read of size 1 at addr ffff88812025f2f0 by task kworker/u17:3/43169

        Workqueue: hci0 hci_rx_work [bluetooth]

        Call Trace:

         <TASK>

         dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4))

         print_report.cold (mm/kasan/report.c:314 mm/kasan/report.c:429)

         ? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth

         kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493)

         ? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth

         l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth

         l2cap_rx (net/bluetooth/l2cap_core.c:7236 net/bluetooth/l2cap_core.c:7271) bluetooth

         ret_from_fork (arch/x86/entry/entry_64.S:306)

         </TASK>

        Allocated by task 43169:

         kasan_save_stack (mm/kasan/common.c:39)

         __kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469)

         kmem_cache_alloc_node (mm/slab.h:750 mm/slub.c:3243 mm/slub.c:3293)

         __alloc_skb (net/core/skbuff.c:414)

         l2cap_recv_frag (./include/net/bluetooth/bluetooth.h:425 net/bluetooth/l2cap_core.c:8329) bluetooth

         l2cap_recv_acldata (net/bluetooth/l2cap_core.c:8442) bluetooth

         hci_rx_work (net/bluetooth/hci_core.c:3642 net/bluetooth/hci_core.c:3832) bluetooth

         process_one_work (kernel/workqueue.c:2289)

         worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2437)

         kthread (kernel/kthread.c:376)

         ret_from_fork (arch/x86/entry/entry_64.S:306)

        Freed by task 27920:

         kasan_save_stack (mm/kasan/common.c:39)

         kasan_set_track (mm/kasan/common.c:45)

         kasan_set_free_info (mm/kasan/generic.c:372)

         ____kasan_slab_free (mm/kasan/common.c:368 mm/kasan/common.c:328)

         slab_free_freelist_hook (mm/slub.c:1780)

         kmem_cache_free (mm/slub.c:3536 mm/slub.c:3553)

         skb_free_datagram (./include/net/sock.h:1578 ./include/net/sock.h:1639 net/core/datagram.c:323)

         bt_sock_recvmsg (net/bluetooth/af_bluetooth.c:295) bluetooth

         l2cap_sock_recvmsg (net/bluetooth/l2cap_sock.c:1212) bluetooth

         sock_read_iter (net/socket.c:1087)

         new_sync_read (./include/linux/fs.h:2052 fs/read_write.c:401)

         vfs_read (fs/read_write.c:482)

         ksys_read (fs/read_write.c:620)

         do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)

         entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)

        Link: https://lore.kernel.org/linux-bluetooth/CAKErNvoqga1WcmoR3-0875esY6TVWFQDandbVZncSiuGPBQXLA@mail.gmail.com/T/#u

        Fixes: d2a7ac5d5d3a ("Bluetooth: Add the ERTM receive state machine")

        Fixes: 4b51dae96731 ("Bluetooth: Add streaming mode receive and incoming packet classifier")

        Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>

        Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

    Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>

    Signed-off-by: Patrick Talbert <ptalbert@redhat.com>

Signed-off-by: Ryan Sullivan <rysulliv@redhat.com>

---

 net/bluetooth/l2cap_core.c | 48 ++++++++++++++++++++++++++++++++------

 1 file changed, 41 insertions(+), 7 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c

index e817ff0607a0..e95c1a019de9 100644

--- a/net/bluetooth/l2cap_core.c

+++ b/net/bluetooth/l2cap_core.c

@@ -6842,6 +6842,7 @@ static int l2cap_rx_state_recv(struct l2cap_chan *chan,

 			       struct l2cap_ctrl *control,

 			       struct sk_buff *skb, u8 event)

 {

+	struct l2cap_ctrl local_control;

 	int err = 0;

 	bool skb_in_use = false;

@@ -6866,15 +6867,32 @@ static int l2cap_rx_state_recv(struct l2cap_chan *chan,

 			chan->buffer_seq = chan->expected_tx_seq;

 			skb_in_use = true;

+			/* l2cap_reassemble_sdu may free skb, hence invalidate

+			 * control, so make a copy in advance to use it after

+			 * l2cap_reassemble_sdu returns and to avoid the race

+			 * condition, for example:

+			 *

+			 * The current thread calls:

+			 *   l2cap_reassemble_sdu

+			 *     chan->ops->recv == l2cap_sock_recv_cb

+			 *       __sock_queue_rcv_skb

+			 * Another thread calls:

+			 *   bt_sock_recvmsg

+			 *     skb_recv_datagram

+			 *     skb_free_datagram

+			 * Then the current thread tries to access control, but

+			 * it was freed by skb_free_datagram.

+			 */

+			local_control = *control;

 			err = l2cap_reassemble_sdu(chan, skb, control);

 			if (err)

 				break;

-			if (control->final) {

+			if (local_control.final) {

 				if (!test_and_clear_bit(CONN_REJ_ACT,

 							&chan->conn_state)) {

-					control->final = 0;

-					l2cap_retransmit_all(chan, control);

+					local_control.final = 0;

+					l2cap_retransmit_all(chan, &local_control);

 					l2cap_ertm_send(chan);

 				}

 			}

@@ -7254,11 +7272,27 @@ static int l2cap_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,

 static int l2cap_stream_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,

 			   struct sk_buff *skb)

 {

+	/* l2cap_reassemble_sdu may free skb, hence invalidate control, so store

+	 * the txseq field in advance to use it after l2cap_reassemble_sdu

+	 * returns and to avoid the race condition, for example:

+	 *

+	 * The current thread calls:

+	 *   l2cap_reassemble_sdu

+	 *     chan->ops->recv == l2cap_sock_recv_cb

+	 *       __sock_queue_rcv_skb

+	 * Another thread calls:

+	 *   bt_sock_recvmsg

+	 *     skb_recv_datagram

+	 *     skb_free_datagram

+	 * Then the current thread tries to access control, but it was freed by

+	 * skb_free_datagram.

+	 */

+	u16 txseq = control->txseq;

+

 	BT_DBG("chan %p, control %p, skb %p, state %d", chan, control, skb,

 	       chan->rx_state);

-	if (l2cap_classify_txseq(chan, control->txseq) ==

-	    L2CAP_TXSEQ_EXPECTED) {

+	if (l2cap_classify_txseq(chan, txseq) == L2CAP_TXSEQ_EXPECTED) {

 		l2cap_pass_to_tx(chan, control);

 		BT_DBG("buffer_seq %u->%u", chan->buffer_seq,

@@ -7281,8 +7315,8 @@ static int l2cap_stream_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,

 		}

 	}

-	chan->last_acked_seq = control->txseq;

-	chan->expected_tx_seq = __next_seq(chan, control->txseq);

+	chan->last_acked_seq = txseq;

+	chan->expected_tx_seq = __next_seq(chan, txseq);

 	return 0;

 }

-- 

2.39.1