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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Or Cohen <orcohen@paloaltonetworks.com>,
	Xin Long <lucien.xin@gmail.com>,
	Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.4 01/32] net/sctp: fix race condition in sctp_destroy_sock
Date: Mon, 26 Apr 2021 09:28:59 +0200	[thread overview]
Message-ID: <20210426072816.631201988@linuxfoundation.org> (raw)
In-Reply-To: <20210426072816.574319312@linuxfoundation.org>

From: Or Cohen <orcohen@paloaltonetworks.com>

commit b166a20b07382b8bc1dcee2a448715c9c2c81b5b upstream.

If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock
held and sp->do_auto_asconf is true, then an element is removed
from the auto_asconf_splist without any proper locking.

This can happen in the following functions:
1. In sctp_accept, if sctp_sock_migrate fails.
2. In inet_create or inet6_create, if there is a bpf program
   attached to BPF_CGROUP_INET_SOCK_CREATE which denies
   creation of the sctp socket.

The bug is fixed by acquiring addr_wq_lock in sctp_destroy_sock
instead of sctp_close.

This addresses CVE-2021-23133.

Reported-by: Or Cohen <orcohen@paloaltonetworks.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Fixes: 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications")
Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/socket.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1567,11 +1567,9 @@ static void sctp_close(struct sock *sk,
 
 	/* Supposedly, no process has access to the socket, but
 	 * the net layers still may.
-	 * Also, sctp_destroy_sock() needs to be called with addr_wq_lock
-	 * held and that should be grabbed before socket lock.
 	 */
-	spin_lock_bh(&net->sctp.addr_wq_lock);
-	bh_lock_sock_nested(sk);
+	local_bh_disable();
+	bh_lock_sock(sk);
 
 	/* Hold the sock, since sk_common_release() will put sock_put()
 	 * and we have just a little more cleanup.
@@ -1580,7 +1578,7 @@ static void sctp_close(struct sock *sk,
 	sk_common_release(sk);
 
 	bh_unlock_sock(sk);
-	spin_unlock_bh(&net->sctp.addr_wq_lock);
+	local_bh_enable();
 
 	sock_put(sk);
 
@@ -4161,9 +4159,6 @@ static int sctp_init_sock(struct sock *s
 	sk_sockets_allocated_inc(sk);
 	sock_prot_inuse_add(net, sk->sk_prot, 1);
 
-	/* Nothing can fail after this block, otherwise
-	 * sctp_destroy_sock() will be called without addr_wq_lock held
-	 */
 	if (net->sctp.default_auto_asconf) {
 		spin_lock(&sock_net(sk)->sctp.addr_wq_lock);
 		list_add_tail(&sp->auto_asconf_list,
@@ -4198,7 +4193,9 @@ static void sctp_destroy_sock(struct soc
 
 	if (sp->do_auto_asconf) {
 		sp->do_auto_asconf = 0;
+		spin_lock_bh(&sock_net(sk)->sctp.addr_wq_lock);
 		list_del(&sp->auto_asconf_list);
+		spin_unlock_bh(&sock_net(sk)->sctp.addr_wq_lock);
 	}
 	sctp_endpoint_free(sp->ep);
 	local_bh_disable();



  reply	other threads:[~2021-04-26  7:30 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26  7:28 [PATCH 4.4 00/32] 4.4.268-rc1 review Greg Kroah-Hartman
2021-04-26  7:28 ` Greg Kroah-Hartman [this message]
2021-04-26  7:29 ` [PATCH 4.4 02/32] Input: nspire-keypad - enable interrupts only when opened Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 03/32] dmaengine: dw: Make it dependent to HAS_IOMEM Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 04/32] ARM: dts: Fix moving mmc devices with aliases for omap4 & 5 Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 05/32] arc: kernel: Return -EFAULT if copy_to_user() fails Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 06/32] neighbour: Disregard DEAD dst in neigh_update Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 07/32] ARM: keystone: fix integer overflow warning Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 08/32] ASoC: fsl_esai: Fix TDM slot setup for I2S mode Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 09/32] net: ieee802154: stop dump llsec keys for monitors Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 10/32] net: ieee802154: stop dump llsec devs " Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 11/32] net: ieee802154: forbid monitor for add llsec dev Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 12/32] net: ieee802154: stop dump llsec devkeys for monitors Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 13/32] net: ieee802154: forbid monitor for add llsec devkey Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 14/32] net: ieee802154: stop dump llsec seclevels for monitors Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 15/32] net: ieee802154: forbid monitor for add llsec seclevel Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 16/32] pcnet32: Use pci_resource_len to validate PCI resource Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 17/32] Input: i8042 - fix Pegatron C15B ID entry Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 18/32] scsi: libsas: Reset num_scatter if libata marks qc as NODATA Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 19/32] net: davicom: Fix regulator not turned off on failed probe Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 20/32] i40e: fix the panic when running bpf in xdpdrv mode Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 21/32] ARM: 9071/1: uprobes: Dont hook on thumb instructions Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 22/32] net: hso: fix null-ptr-deref during tty device unregistration Greg Kroah-Hartman
2021-04-26  7:36   ` Johan Hovold
2021-04-26  7:58     ` Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 23/32] ext4: correct error label in ext4_rename() Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 24/32] ARM: dts: Fix swapped mmc order for omap3 Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 25/32] s390/entry: save the caller of psw_idle Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 26/32] xen-netback: Check for hotplug-status existence before watching Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 27/32] cavium/liquidio: Fix duplicate argument Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 28/32] ia64: fix discontig.c section mismatches Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 29/32] ia64: tools: remove duplicate definition of ia64_mf() on ia64 Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 30/32] compiler.h: enable builtin overflow checkers and add fallback code Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 31/32] overflow.h: Add allocation size calculation helpers Greg Kroah-Hartman
2021-04-26  7:29 ` [PATCH 4.4 32/32] x86/crash: Fix crash_setup_memmap_entries() out-of-bounds access Greg Kroah-Hartman
2021-04-26  9:05 ` [PATCH 4.4 00/32] 4.4.268-rc1 review Pavel Machek
2021-04-26 13:04 ` Jon Hunter
2021-04-26 18:32 ` Guenter Roeck
2021-04-26 23:48 ` Shuah Khan
2021-04-27  7:48 ` Naresh Kamboju

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