5.11-stable patches

added patches:
	revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch
	sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch

diff --git a/queue-5.11/revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch b/queue-5.11/revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch
new file mode 100644 (file)
index 0000000..26c0c9a
--- /dev/null
+++ b/queue-5.11/revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch
@@ -0,0 +1,80 @@
+From 01bfe5e8e428b475982a98a46cca5755726f3f7f Mon Sep 17 00:00:00 2001
+From: Xin Long <lucien.xin@gmail.com>
+Date: Mon, 3 May 2021 05:11:41 +0800
+Subject: Revert "net/sctp: fix race condition in sctp_destroy_sock"
+
+From: Xin Long <lucien.xin@gmail.com>
+
+commit 01bfe5e8e428b475982a98a46cca5755726f3f7f upstream.
+
+This reverts commit b166a20b07382b8bc1dcee2a448715c9c2c81b5b.
+
+This one has to be reverted as it introduced a dead lock, as
+syzbot reported:
+
+       CPU0                    CPU1
+       ----                    ----
+  lock(&net->sctp.addr_wq_lock);
+                               lock(slock-AF_INET6);
+                               lock(&net->sctp.addr_wq_lock);
+  lock(slock-AF_INET6);
+
+CPU0 is the thread of sctp_addr_wq_timeout_handler(), and CPU1
+is that of sctp_close().
+
+The original issue this commit fixed will be fixed in the next
+patch.
+
+Reported-by: syzbot+959223586843e69a2674@syzkaller.appspotmail.com
+Signed-off-by: Xin Long <lucien.xin@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, 8 insertions(+), 5 deletions(-)
+
+--- a/net/sctp/socket.c
++++ b/net/sctp/socket.c
+@@ -1520,9 +1520,11 @@ 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.
+        */
+-      local_bh_disable();
+-      bh_lock_sock(sk);
++      spin_lock_bh(&net->sctp.addr_wq_lock);
++      bh_lock_sock_nested(sk);
+ 
+       /* Hold the sock, since sk_common_release() will put sock_put()
+        * and we have just a little more cleanup.
+@@ -1531,7 +1533,7 @@ static void sctp_close(struct sock *sk,
+       sk_common_release(sk);
+ 
+       bh_unlock_sock(sk);
+-      local_bh_enable();
++      spin_unlock_bh(&net->sctp.addr_wq_lock);
+ 
+       sock_put(sk);
+ 
+@@ -4991,6 +4993,9 @@ 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,
+@@ -5025,9 +5030,7 @@ 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();

diff --git a/queue-5.11/sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch b/queue-5.11/sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch
new file mode 100644 (file)
index 0000000..4c39e0e
--- /dev/null
+++ b/queue-5.11/sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch
@@ -0,0 +1,103 @@
+From 34e5b01186858b36c4d7c87e1a025071e8e2401f Mon Sep 17 00:00:00 2001
+From: Xin Long <lucien.xin@gmail.com>
+Date: Mon, 3 May 2021 05:11:42 +0800
+Subject: sctp: delay auto_asconf init until binding the first addr
+
+From: Xin Long <lucien.xin@gmail.com>
+
+commit 34e5b01186858b36c4d7c87e1a025071e8e2401f upstream.
+
+As Or Cohen described:
+
+  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.
+
+This patch is to fix it by moving the auto_asconf init out of
+sctp_init_sock(), by which inet_create()/inet6_create() won't
+need to operate it in sctp_destroy_sock() when calling
+sk_common_release().
+
+It also makes more sense to do auto_asconf init while binding the
+first addr, as auto_asconf actually requires an ANY addr bind,
+see it in sctp_addr_wq_timeout_handler().
+
+This addresses CVE-2021-23133.
+
+Fixes: 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications")
+Reported-by: Or Cohen <orcohen@paloaltonetworks.com>
+Signed-off-by: Xin Long <lucien.xin@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/sctp/socket.c |   31 +++++++++++++++++--------------
+ 1 file changed, 17 insertions(+), 14 deletions(-)
+
+--- a/net/sctp/socket.c
++++ b/net/sctp/socket.c
+@@ -357,6 +357,18 @@ static struct sctp_af *sctp_sockaddr_af(
+       return af;
+ }
+ 
++static void sctp_auto_asconf_init(struct sctp_sock *sp)
++{
++      struct net *net = sock_net(&sp->inet.sk);
++
++      if (net->sctp.default_auto_asconf) {
++              spin_lock(&net->sctp.addr_wq_lock);
++              list_add_tail(&sp->auto_asconf_list, &net->sctp.auto_asconf_splist);
++              spin_unlock(&net->sctp.addr_wq_lock);
++              sp->do_auto_asconf = 1;
++      }
++}
++
+ /* Bind a local address either to an endpoint or to an association.  */
+ static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
+ {
+@@ -418,8 +430,10 @@ static int sctp_do_bind(struct sock *sk,
+               return -EADDRINUSE;
+ 
+       /* Refresh ephemeral port.  */
+-      if (!bp->port)
++      if (!bp->port) {
+               bp->port = inet_sk(sk)->inet_num;
++              sctp_auto_asconf_init(sp);
++      }
+ 
+       /* Add the address to the bind address list.
+        * Use GFP_ATOMIC since BHs will be disabled.
+@@ -4993,19 +5007,6 @@ 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,
+-                  &net->sctp.auto_asconf_splist);
+-              sp->do_auto_asconf = 1;
+-              spin_unlock(&sock_net(sk)->sctp.addr_wq_lock);
+-      } else {
+-              sp->do_auto_asconf = 0;
+-      }
+-
+       local_bh_enable();
+ 
+       return 0;
+@@ -9401,6 +9402,8 @@ static int sctp_sock_migrate(struct sock
+                       return err;
+       }
+ 
++      sctp_auto_asconf_init(newsp);
++
+       /* Move any messages in the old socket's receive queue that are for the
+        * peeled off association to the new socket's receive queue.
+        */

diff --git a/queue-5.11/series b/queue-5.11/series
index d9a074ae2692148b5e70d1284eacd0c672c7f801..ded73ba8c5f4dfb97bafc7c8de70b5361cf80bd4 100644 (file)
--- a/queue-5.11/series
+++ b/queue-5.11/series
@@ -597,3 +597,5 @@ bpf-ringbuf-deny-reserve-of-buffers-larger-than-ringbuf.patch
 bpf-prevent-writable-memory-mapping-of-read-only-ringbuf-pages.patch
 net-only-allow-init-netns-to-set-default-tcp-cong-to-a-restricted-algo.patch
 smp-fix-smp_call_function_single_async-prototype.patch
+revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch
+sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch