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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: John Fastabend <john.fastabend@gmail.com>,
	Jakub Sitnicki <jakub@cloudflare.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 07/60] bpf: sockmap, fix use after free from sleep in psock backlog workqueue
Date: Wed, 26 Jun 2019 20:35:22 -0400
Message-ID: <20190627003616.20767-7-sashal@kernel.org> (raw)
In-Reply-To: <20190627003616.20767-1-sashal@kernel.org>

From: John Fastabend <john.fastabend@gmail.com>

[ Upstream commit bd95e678e0f6e18351ecdc147ca819145db9ed7b ]

Backlog work for psock (sk_psock_backlog) might sleep while waiting
for memory to free up when sending packets. However, while sleeping
the socket may be closed and removed from the map by the user space
side.

This breaks an assumption in sk_stream_wait_memory, which expects the
wait queue to be still there when it wakes up resulting in a
use-after-free shown below. To fix his mark sendmsg as MSG_DONTWAIT
to avoid the sleep altogether. We already set the flag for the
sendpage case but we missed the case were sendmsg is used.
Sockmap is currently the only user of skb_send_sock_locked() so only
the sockmap paths should be impacted.

==================================================================
BUG: KASAN: use-after-free in remove_wait_queue+0x31/0x70
Write of size 8 at addr ffff888069a0c4e8 by task kworker/0:2/110

CPU: 0 PID: 110 Comm: kworker/0:2 Not tainted 5.0.0-rc2-00335-g28f9d1a3d4fe-dirty #14
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-2.fc27 04/01/2014
Workqueue: events sk_psock_backlog
Call Trace:
 print_address_description+0x6e/0x2b0
 ? remove_wait_queue+0x31/0x70
 kasan_report+0xfd/0x177
 ? remove_wait_queue+0x31/0x70
 ? remove_wait_queue+0x31/0x70
 remove_wait_queue+0x31/0x70
 sk_stream_wait_memory+0x4dd/0x5f0
 ? sk_stream_wait_close+0x1b0/0x1b0
 ? wait_woken+0xc0/0xc0
 ? tcp_current_mss+0xc5/0x110
 tcp_sendmsg_locked+0x634/0x15d0
 ? tcp_set_state+0x2e0/0x2e0
 ? __kasan_slab_free+0x1d1/0x230
 ? kmem_cache_free+0x70/0x140
 ? sk_psock_backlog+0x40c/0x4b0
 ? process_one_work+0x40b/0x660
 ? worker_thread+0x82/0x680
 ? kthread+0x1b9/0x1e0
 ? ret_from_fork+0x1f/0x30
 ? check_preempt_curr+0xaf/0x130
 ? iov_iter_kvec+0x5f/0x70
 ? kernel_sendmsg_locked+0xa0/0xe0
 skb_send_sock_locked+0x273/0x3c0
 ? skb_splice_bits+0x180/0x180
 ? start_thread+0xe0/0xe0
 ? update_min_vruntime.constprop.27+0x88/0xc0
 sk_psock_backlog+0xb3/0x4b0
 ? strscpy+0xbf/0x1e0
 process_one_work+0x40b/0x660
 worker_thread+0x82/0x680
 ? process_one_work+0x660/0x660
 kthread+0x1b9/0x1e0
 ? __kthread_create_on_node+0x250/0x250
 ret_from_fork+0x1f/0x30

Fixes: 20bf50de3028c ("skbuff: Function to send an skbuf on a socket")
Reported-by: Jakub Sitnicki <jakub@cloudflare.com>
Tested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/skbuff.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 8b5768113acd..9b9f696281a9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2302,6 +2302,7 @@ int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
 		kv.iov_base = skb->data + offset;
 		kv.iov_len = slen;
 		memset(&msg, 0, sizeof(msg));
+		msg.msg_flags = MSG_DONTWAIT;
 
 		ret = kernel_sendmsg_locked(sk, &msg, &kv, 1, slen);
 		if (ret <= 0)
-- 
2.20.1


  parent reply index

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190627003616.20767-1-sashal@kernel.org>
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 04/60] samples, bpf: fix to change the buffer size for read() Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 05/60] samples, bpf: suppress compiler warning Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 06/60] mac80211: fix rate reporting inside cfg80211_calculate_bitrate_he() Sasha Levin
2019-06-27  0:35 ` Sasha Levin [this message]
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 11/60] mac80211: mesh: fix RCU warning Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 12/60] mac80211: free peer keys before vif down in mesh Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 13/60] mwifiex: Fix possible buffer overflows at parsing bss descriptor Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 14/60] mwifiex: Abort at too short BSS descriptor element Sasha Levin
2019-06-28 22:58   ` Brian Norris
2019-07-10 14:51     ` Sasha Levin
2019-07-10 21:12       ` Brian Norris
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 15/60] iwlwifi: Fix double-free problems in iwl_req_fw_callback() Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 16/60] mwifiex: Fix heap overflow in mwifiex_uap_parse_tail_ies() Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 17/60] bpf: udp: Avoid calling reuseport's bpf_prog from udp_gro Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 18/60] netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 20/60] netfilter: ipv6: nf_defrag: accept duplicate fragments again Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 21/60] dt-bindings: can: mcp251x: add mcp25625 support Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 22/60] can: mcp251x: add support for mcp25625 Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 23/60] can: m_can: implement errata "Needless activation of MRAF irq" Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 24/60] can: af_can: Fix error path of can_init() Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 25/60] net: phy: rename Asix Electronics PHY driver Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 26/60] ibmvnic: Do not close unopened driver during reset Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 27/60] ibmvnic: Refresh device multicast list after reset Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 28/60] ibmvnic: Fix unchecked return codes of memory allocations Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 31/60] bpf: lpm_trie: check left child of last leftmost node for NULL Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 37/60] mlxsw: spectrum: Disallow prio-tagged packets when PVID is removed Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 40/60] mac80211: only warn once on chanctx_conf being NULL Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 41/60] mac80211: do not start any work during reconfigure flow Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 42/60] bpf, devmap: Fix premature entry free on destroying map Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 43/60] bpf, devmap: Add missing bulk queue free Sasha Levin
2019-06-27  0:35 ` [PATCH AUTOSEL 4.19 44/60] bpf, devmap: Add missing RCU read lock on flush Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 45/60] bpf, x64: fix stack layout of JITed bpf code Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 46/60] qmi_wwan: add support for QMAP padding in the RX path Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 47/60] qmi_wwan: avoid RCU stalls on device disconnect when in QMAP mode Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 48/60] qmi_wwan: extend permitted QMAP mux_id value range Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 49/60] bpf: fix nested bpf tracepoints with per-cpu data Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 52/60] bnx2x: Check if transceiver implements DDM before access Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 54/60] ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 55/60] net: lio_core: fix potential sign-extension overflow on large shift Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 58/60] net: dsa: mv88e6xxx: fix shift of FID bits in mv88e6185_g1_vtu_loadpurge() Sasha Levin
2019-06-27  0:36 ` [PATCH AUTOSEL 4.19 60/60] net :sunrpc :clnt :Fix xps refcount imbalance on the error path Sasha Levin

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