net: CVE-2019-11815

net: rds: force to destroy connection if t_sock is NULL in rds_tcp_kill_sock().

References:
https://nvd.nist.gov/vuln/detail/CVE-2019-11815
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=a1aa69beac4d88dfb892a95ee04fe6f932803952

Change-Id: Idd83d9a8e84f1560a660dc028d6fc191efad8927
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>

2 files changed, 155 insertions, 0 deletions

diff --git a/patches/cve/4.9.x.scc b/patches/cve/4.9.x.scc
index 771e9b7..6259efc 100644
--- a/patches/cve/4.9.x.scc
+++ b/patches/cve/4.9.x.scc
@@ -72,3 +72,6 @@ patch CVE-2019-9213-mm-enforce-min-addr-even-if-capable-in-expand_downwa.patch
 
 #CVEs fixed in 4.9.163:
 patch CVE-2019-8980-exec-Fix-mem-leak-in-kernel_read_file.patch
+
+#CVEs fixed in 4.9.169:
+patch CVE-2019-11815-net-rds-force-to-destroy-connection-if-t_sock-is-NUL.patch
diff --git a/patches/cve/CVE-2019-11815-net-rds-force-to-destroy-connection-if-t_sock-is-NUL.patch b/patches/cve/CVE-2019-11815-net-rds-force-to-destroy-connection-if-t_sock-is-NUL.patch
new file mode 100644
index 0000000..aba1d1c
--- /dev/null
+++ b/patches/cve/CVE-2019-11815-net-rds-force-to-destroy-connection-if-t_sock-is-NUL.patch
@@ -0,0 +1,152 @@
+From a1aa69beac4d88dfb892a95ee04fe6f932803952 Mon Sep 17 00:00:00 2001
+From: Mao Wenan <maowenan@huawei.com>
+Date: Thu, 28 Mar 2019 17:10:56 +0800
+Subject: [PATCH] net: rds: force to destroy connection if t_sock is NULL in
+ rds_tcp_kill_sock().
+
+[ Upstream commit cb66ddd156203daefb8d71158036b27b0e2caf63 ]
+
+When it is to cleanup net namespace, rds_tcp_exit_net() will call
+rds_tcp_kill_sock(), if t_sock is NULL, it will not call
+rds_conn_destroy(), rds_conn_path_destroy() and rds_tcp_conn_free() to free
+connection, and the worker cp_conn_w is not stopped, afterwards the net is freed in
+net_drop_ns(); While cp_conn_w rds_connect_worker() will call rds_tcp_conn_path_connect()
+and reference 'net' which has already been freed.
+
+In rds_tcp_conn_path_connect(), rds_tcp_set_callbacks() will set t_sock = sock before
+sock->ops->connect, but if connect() is failed, it will call
+rds_tcp_restore_callbacks() and set t_sock = NULL, if connect is always
+failed, rds_connect_worker() will try to reconnect all the time, so
+rds_tcp_kill_sock() will never to cancel worker cp_conn_w and free the
+connections.
+
+Therefore, the condition !tc->t_sock is not needed if it is going to do
+cleanup_net->rds_tcp_exit_net->rds_tcp_kill_sock, because tc->t_sock is always
+NULL, and there is on other path to cancel cp_conn_w and free
+connection. So this patch is to fix this.
+
+rds_tcp_kill_sock():
+...
+if (net != c_net || !tc->t_sock)
+...
+Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
+
+==================================================================
+BUG: KASAN: use-after-free in inet_create+0xbcc/0xd28
+net/ipv4/af_inet.c:340
+Read of size 4 at addr ffff8003496a4684 by task kworker/u8:4/3721
+
+CPU: 3 PID: 3721 Comm: kworker/u8:4 Not tainted 5.1.0 #11
+Hardware name: linux,dummy-virt (DT)
+Workqueue: krdsd rds_connect_worker
+Call trace:
+ dump_backtrace+0x0/0x3c0 arch/arm64/kernel/time.c:53
+ show_stack+0x28/0x38 arch/arm64/kernel/traps.c:152
+ __dump_stack lib/dump_stack.c:77 [inline]
+ dump_stack+0x120/0x188 lib/dump_stack.c:113
+ print_address_description+0x68/0x278 mm/kasan/report.c:253
+ kasan_report_error mm/kasan/report.c:351 [inline]
+ kasan_report+0x21c/0x348 mm/kasan/report.c:409
+ __asan_report_load4_noabort+0x30/0x40 mm/kasan/report.c:429
+ inet_create+0xbcc/0xd28 net/ipv4/af_inet.c:340
+ __sock_create+0x4f8/0x770 net/socket.c:1276
+ sock_create_kern+0x50/0x68 net/socket.c:1322
+ rds_tcp_conn_path_connect+0x2b4/0x690 net/rds/tcp_connect.c:114
+ rds_connect_worker+0x108/0x1d0 net/rds/threads.c:175
+ process_one_work+0x6e8/0x1700 kernel/workqueue.c:2153
+ worker_thread+0x3b0/0xdd0 kernel/workqueue.c:2296
+ kthread+0x2f0/0x378 kernel/kthread.c:255
+ ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:1117
+
+Allocated by task 687:
+ save_stack mm/kasan/kasan.c:448 [inline]
+ set_track mm/kasan/kasan.c:460 [inline]
+ kasan_kmalloc+0xd4/0x180 mm/kasan/kasan.c:553
+ kasan_slab_alloc+0x14/0x20 mm/kasan/kasan.c:490
+ slab_post_alloc_hook mm/slab.h:444 [inline]
+ slab_alloc_node mm/slub.c:2705 [inline]
+ slab_alloc mm/slub.c:2713 [inline]
+ kmem_cache_alloc+0x14c/0x388 mm/slub.c:2718
+ kmem_cache_zalloc include/linux/slab.h:697 [inline]
+ net_alloc net/core/net_namespace.c:384 [inline]
+ copy_net_ns+0xc4/0x2d0 net/core/net_namespace.c:424
+ create_new_namespaces+0x300/0x658 kernel/nsproxy.c:107
+ unshare_nsproxy_namespaces+0xa0/0x198 kernel/nsproxy.c:206
+ ksys_unshare+0x340/0x628 kernel/fork.c:2577
+ __do_sys_unshare kernel/fork.c:2645 [inline]
+ __se_sys_unshare kernel/fork.c:2643 [inline]
+ __arm64_sys_unshare+0x38/0x58 kernel/fork.c:2643
+ __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
+ invoke_syscall arch/arm64/kernel/syscall.c:47 [inline]
+ el0_svc_common+0x168/0x390 arch/arm64/kernel/syscall.c:83
+ el0_svc_handler+0x60/0xd0 arch/arm64/kernel/syscall.c:129
+ el0_svc+0x8/0xc arch/arm64/kernel/entry.S:960
+
+Freed by task 264:
+ save_stack mm/kasan/kasan.c:448 [inline]
+ set_track mm/kasan/kasan.c:460 [inline]
+ __kasan_slab_free+0x114/0x220 mm/kasan/kasan.c:521
+ kasan_slab_free+0x10/0x18 mm/kasan/kasan.c:528
+ slab_free_hook mm/slub.c:1370 [inline]
+ slab_free_freelist_hook mm/slub.c:1397 [inline]
+ slab_free mm/slub.c:2952 [inline]
+ kmem_cache_free+0xb8/0x3a8 mm/slub.c:2968
+ net_free net/core/net_namespace.c:400 [inline]
+ net_drop_ns.part.6+0x78/0x90 net/core/net_namespace.c:407
+ net_drop_ns net/core/net_namespace.c:406 [inline]
+ cleanup_net+0x53c/0x6d8 net/core/net_namespace.c:569
+ process_one_work+0x6e8/0x1700 kernel/workqueue.c:2153
+ worker_thread+0x3b0/0xdd0 kernel/workqueue.c:2296
+ kthread+0x2f0/0x378 kernel/kthread.c:255
+ ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:1117
+
+The buggy address belongs to the object at ffff8003496a3f80
+ which belongs to the cache net_namespace of size 7872
+The buggy address is located 1796 bytes inside of
+ 7872-byte region [ffff8003496a3f80, ffff8003496a5e40)
+The buggy address belongs to the page:
+page:ffff7e000d25a800 count:1 mapcount:0 mapping:ffff80036ce4b000
+index:0x0 compound_mapcount: 0
+flags: 0xffffe0000008100(slab|head)
+raw: 0ffffe0000008100 dead000000000100 dead000000000200 ffff80036ce4b000
+raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
+page dumped because: kasan: bad access detected
+
+Memory state around the buggy address:
+ ffff8003496a4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+ ffff8003496a4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+>ffff8003496a4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+                   ^
+ ffff8003496a4700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+ ffff8003496a4780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+==================================================================
+
+CVE: CVE-2019-11815
+Upstream-Status: Backport [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=a1aa69beac4d88dfb892a95ee04fe6f932803952]
+
+Fixes: 467fa15356ac("RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.")
+Reported-by: Hulk Robot <hulkci@huawei.com>
+Signed-off-by: Mao Wenan <maowenan@huawei.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
+---
+ net/rds/tcp.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/net/rds/tcp.c b/net/rds/tcp.c
+index d36effbf7614..2daba5316caa 100644
+--- a/net/rds/tcp.c
++++ b/net/rds/tcp.c
+@@ -527,7 +527,7 @@ static void rds_tcp_kill_sock(struct net *net)
+        list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
+                struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
+ 
+-               if (net != c_net || !tc->t_sock)
++               if (net != c_net)
+                        continue;
+                if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
+                        list_move_tail(&tc->t_tcp_node, &tmp_list);
+-- 
+2.20.1
+