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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Lin Ma <linma@zju.edu.cn>, Hanjie Wu <nagi@zju.edu.cn>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	jreuter@yaina.de, kuba@kernel.org, linux-hams@vger.kernel.org,
	netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.15 17/26] ax25: NPD bug when detaching AX25 device
Date: Mon, 27 Dec 2021 14:03:18 -0500	[thread overview]
Message-ID: <20211227190327.1042326-17-sashal@kernel.org> (raw)
In-Reply-To: <20211227190327.1042326-1-sashal@kernel.org>

From: Lin Ma <linma@zju.edu.cn>

[ Upstream commit 1ade48d0c27d5da1ccf4b583d8c5fc8b534a3ac8 ]

The existing cleanup routine implementation is not well synchronized
with the syscall routine. When a device is detaching, below race could
occur.

static int ax25_sendmsg(...) {
  ...
  lock_sock()
  ax25 = sk_to_ax25(sk);
  if (ax25->ax25_dev == NULL) // CHECK
  ...
  ax25_queue_xmit(skb, ax25->ax25_dev->dev); // USE
  ...
}

static void ax25_kill_by_device(...) {
  ...
  if (s->ax25_dev == ax25_dev) {
    s->ax25_dev = NULL;
    ...
}

Other syscall functions like ax25_getsockopt, ax25_getname,
ax25_info_show also suffer from similar races. To fix them, this patch
introduce lock_sock() into ax25_kill_by_device in order to guarantee
that the nullify action in cleanup routine cannot proceed when another
socket request is pending.

Signed-off-by: Hanjie Wu <nagi@zju.edu.cn>
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ax25/af_ax25.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 2631efc6e359f..aa7785687e757 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -85,8 +85,10 @@ static void ax25_kill_by_device(struct net_device *dev)
 again:
 	ax25_for_each(s, &ax25_list) {
 		if (s->ax25_dev == ax25_dev) {
-			s->ax25_dev = NULL;
 			spin_unlock_bh(&ax25_list_lock);
+			lock_sock(s->sk);
+			s->ax25_dev = NULL;
+			release_sock(s->sk);
 			ax25_disconnect(s, ENETUNREACH);
 			spin_lock_bh(&ax25_list_lock);
 
-- 
2.34.1


  parent reply	other threads:[~2021-12-27 19:05 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-27 19:03 [PATCH AUTOSEL 5.15 01/26] pinctrl: mediatek: fix global-out-of-bounds issue Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 02/26] Input: i8042 - add deferred probe support Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 03/26] Input: iqs626a - prohibit inlining of channel parsing functions Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 04/26] ASoC: SOF: Intel: pci-tgl: add ADL-N support Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 05/26] ASoC: SOF: Intel: pci-tgl: add new ADL-P variant Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 06/26] Input: i8042 - enable deferred probe quirk for ASUS UM325UA Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 07/26] Input: goodix - add id->model mapping for the "9111" model Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 08/26] hwmon: (lm90) Do not report 'busy' status bit as alarm Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 09/26] ASoC: rt5682: fix the wrong jack type detected Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 10/26] ASoC: tas2770: Fix setting of high sample rates Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 11/26] Revert "x86/boot: Pull up cmdline preparation and early param parsing" Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 12/26] tomoyo: Check exceeded quota early in tomoyo_domain_quota_is_ok() Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 13/26] tomoyo: use hwight16() " Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 14/26] x86/boot: Move EFI range reservation after cmdline parsing Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 15/26] net/sched: Extend qdisc control block with tc control block Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 16/26] tun: avoid double free in tun_free_netdev Sasha Levin
2021-12-27 19:03 ` Sasha Levin [this message]
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 18/26] Input: elants_i2c - do not check Remark ID on eKTH3900/eKTH5312 Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 19/26] phonet/pep: refuse to enable an unbound pipe Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 20/26] parisc: Clear stale IIR value on instruction access rights trap Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 21/26] platform/mellanox: mlxbf-pmc: Fix an IS_ERR() vs NULL bug in mlxbf_pmc_map_counters Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 22/26] platform/x86: apple-gmux: use resource_size() with res Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 23/26] memblock: fix memblock_phys_alloc() section mismatch error Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 24/26] ALSA: hda: intel-sdw-acpi: harden detection of controller Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 25/26] ALSA: hda: intel-sdw-acpi: go through HDAS ACPI at max depth of 2 Sasha Levin
2021-12-27 19:03 ` [PATCH AUTOSEL 5.15 26/26] r8152: sync ocp base Sasha Levin

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