From: Greg Kroah-Hartman Date: Wed, 12 May 2021 14:04:02 +0000 (+0200) Subject: 5.12-stable patches X-Git-Tag: v5.4.119~12 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4b87bed4dbe5a4b7e6ffa7d0de6c903d2f6492b5;p=thirdparty%2Fkernel%2Fstable-queue.git 5.12-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-5.12/revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch b/queue-5.12/revert-net-sctp-fix-race-condition-in-sctp_destroy_sock.patch new file mode 100644 index 00000000000..26c0c9ab14b --- /dev/null +++ b/queue-5.12/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 +Date: Mon, 3 May 2021 05:11:41 +0800 +Subject: Revert "net/sctp: fix race condition in sctp_destroy_sock" + +From: Xin Long + +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 +Signed-off-by: David S. Miller +Signed-off-by: Greg Kroah-Hartman +--- + 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-5.12/sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch b/queue-5.12/sctp-delay-auto_asconf-init-until-binding-the-first-addr.patch new file mode 100644 index 00000000000..4c39e0e64be --- /dev/null +++ b/queue-5.12/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 +Date: Mon, 3 May 2021 05:11:42 +0800 +Subject: sctp: delay auto_asconf init until binding the first addr + +From: Xin Long + +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 +Signed-off-by: Xin Long +Signed-off-by: David S. Miller +Signed-off-by: Greg Kroah-Hartman +--- + 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-5.12/series b/queue-5.12/series index 8d12da0c3be..9cb77613b5e 100644 --- a/queue-5.12/series +++ b/queue-5.12/series @@ -673,3 +673,5 @@ 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