| From 75b2421a4d831c05eea1b0c7616fcc0cd8df7bbb Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 10 Jul 2023 17:40:51 +0800 |
| Subject: xfrm: fix slab-use-after-free in decode_session6 |
| |
| From: Zhengchao Shao <shaozhengchao@huawei.com> |
| |
| [ Upstream commit 53223f2ed1ef5c90dad814daaaefea4e68a933c8 ] |
| |
| When the xfrm device is set to the qdisc of the sfb type, the cb field |
| of the sent skb may be modified during enqueuing. Then, |
| slab-use-after-free may occur when the xfrm device sends IPv6 packets. |
| |
| The stack information is as follows: |
| BUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890 |
| Read of size 1 at addr ffff8881111458ef by task swapper/3/0 |
| CPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.4.0-next-20230707 #409 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 |
| Call Trace: |
| <IRQ> |
| dump_stack_lvl+0xd9/0x150 |
| print_address_description.constprop.0+0x2c/0x3c0 |
| kasan_report+0x11d/0x130 |
| decode_session6+0x103f/0x1890 |
| __xfrm_decode_session+0x54/0xb0 |
| xfrmi_xmit+0x173/0x1ca0 |
| dev_hard_start_xmit+0x187/0x700 |
| sch_direct_xmit+0x1a3/0xc30 |
| __qdisc_run+0x510/0x17a0 |
| __dev_queue_xmit+0x2215/0x3b10 |
| neigh_connected_output+0x3c2/0x550 |
| ip6_finish_output2+0x55a/0x1550 |
| ip6_finish_output+0x6b9/0x1270 |
| ip6_output+0x1f1/0x540 |
| ndisc_send_skb+0xa63/0x1890 |
| ndisc_send_rs+0x132/0x6f0 |
| addrconf_rs_timer+0x3f1/0x870 |
| call_timer_fn+0x1a0/0x580 |
| expire_timers+0x29b/0x4b0 |
| run_timer_softirq+0x326/0x910 |
| __do_softirq+0x1d4/0x905 |
| irq_exit_rcu+0xb7/0x120 |
| sysvec_apic_timer_interrupt+0x97/0xc0 |
| </IRQ> |
| <TASK> |
| asm_sysvec_apic_timer_interrupt+0x1a/0x20 |
| RIP: 0010:intel_idle_hlt+0x23/0x30 |
| Code: 1f 84 00 00 00 00 00 f3 0f 1e fa 41 54 41 89 d4 0f 1f 44 00 00 66 90 0f 1f 44 00 00 0f 00 2d c4 9f ab 00 0f 1f 44 00 00 fb f4 <fa> 44 89 e0 41 5c c3 66 0f 1f 44 00 00 f3 0f 1e fa 41 54 41 89 d4 |
| RSP: 0018:ffffc90000197d78 EFLAGS: 00000246 |
| RAX: 00000000000a83c3 RBX: ffffe8ffffd09c50 RCX: ffffffff8a22d8e5 |
| RDX: 0000000000000001 RSI: ffffffff8d3f8080 RDI: ffffe8ffffd09c50 |
| RBP: ffffffff8d3f8080 R08: 0000000000000001 R09: ffffed1026ba6d9d |
| R10: ffff888135d36ceb R11: 0000000000000001 R12: 0000000000000001 |
| R13: ffffffff8d3f8100 R14: 0000000000000001 R15: 0000000000000000 |
| cpuidle_enter_state+0xd3/0x6f0 |
| cpuidle_enter+0x4e/0xa0 |
| do_idle+0x2fe/0x3c0 |
| cpu_startup_entry+0x18/0x20 |
| start_secondary+0x200/0x290 |
| secondary_startup_64_no_verify+0x167/0x16b |
| </TASK> |
| Allocated by task 939: |
| kasan_save_stack+0x22/0x40 |
| kasan_set_track+0x25/0x30 |
| __kasan_slab_alloc+0x7f/0x90 |
| kmem_cache_alloc_node+0x1cd/0x410 |
| kmalloc_reserve+0x165/0x270 |
| __alloc_skb+0x129/0x330 |
| inet6_ifa_notify+0x118/0x230 |
| __ipv6_ifa_notify+0x177/0xbe0 |
| addrconf_dad_completed+0x133/0xe00 |
| addrconf_dad_work+0x764/0x1390 |
| process_one_work+0xa32/0x16f0 |
| worker_thread+0x67d/0x10c0 |
| kthread+0x344/0x440 |
| ret_from_fork+0x1f/0x30 |
| The buggy address belongs to the object at ffff888111145800 |
| which belongs to the cache skbuff_small_head of size 640 |
| The buggy address is located 239 bytes inside of |
| freed 640-byte region [ffff888111145800, ffff888111145a80) |
| |
| As commit f855691975bb ("xfrm6: Fix the nexthdr offset in |
| _decode_session6.") showed, xfrm_decode_session was originally intended |
| only for the receive path. IP6CB(skb)->nhoff is not set during |
| transmission. Therefore, set the cb field in the skb to 0 before |
| sending packets. |
| |
| Fixes: f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.") |
| Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> |
| Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/xfrm/xfrm_interface_core.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/net/xfrm/xfrm_interface_core.c b/net/xfrm/xfrm_interface_core.c |
| index e4f21a6924153..4eeec33675754 100644 |
| --- a/net/xfrm/xfrm_interface_core.c |
| +++ b/net/xfrm/xfrm_interface_core.c |
| @@ -403,8 +403,8 @@ static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev) |
| |
| switch (skb->protocol) { |
| case htons(ETH_P_IPV6): |
| - xfrm_decode_session(skb, &fl, AF_INET6); |
| memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); |
| + xfrm_decode_session(skb, &fl, AF_INET6); |
| if (!dst) { |
| fl.u.ip6.flowi6_oif = dev->ifindex; |
| fl.u.ip6.flowi6_flags |= FLOWI_FLAG_ANYSRC; |
| @@ -418,8 +418,8 @@ static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev) |
| } |
| break; |
| case htons(ETH_P_IP): |
| - xfrm_decode_session(skb, &fl, AF_INET); |
| memset(IPCB(skb), 0, sizeof(*IPCB(skb))); |
| + xfrm_decode_session(skb, &fl, AF_INET); |
| if (!dst) { |
| struct rtable *rt; |
| |
| -- |
| 2.40.1 |
| |
