releases/4.4.172/tipc-fix-uninit-value-in-tipc_nl_compat_link_reset_stats.patch

   1 From 8b66fee7f8ee18f9c51260e7a43ab37db5177a05 Mon Sep 17 00:00:00 2001
   2 From: Ying Xue <ying.xue@windriver.com>
   3 Date: Mon, 14 Jan 2019 17:22:25 +0800
   4 Subject: tipc: fix uninit-value in tipc_nl_compat_link_reset_stats
   5
   6 From: Ying Xue <ying.xue@windriver.com>
   7
   8 commit 8b66fee7f8ee18f9c51260e7a43ab37db5177a05 upstream.
   9
  10 syzbot reports following splat:
  11
  12 BUG: KMSAN: uninit-value in strlen+0x3b/0xa0 lib/string.c:486
  13 CPU: 1 PID: 11057 Comm: syz-executor0 Not tainted 4.20.0-rc7+ #2
  14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  15 Call Trace:
  16  __dump_stack lib/dump_stack.c:77 [inline]
  17  dump_stack+0x173/0x1d0 lib/dump_stack.c:113
  18  kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
  19  __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:295
  20  strlen+0x3b/0xa0 lib/string.c:486
  21  nla_put_string include/net/netlink.h:1154 [inline]
  22  tipc_nl_compat_link_reset_stats+0x1f0/0x360 net/tipc/netlink_compat.c:760
  23  __tipc_nl_compat_doit net/tipc/netlink_compat.c:311 [inline]
  24  tipc_nl_compat_doit+0x3aa/0xaf0 net/tipc/netlink_compat.c:344
  25  tipc_nl_compat_handle net/tipc/netlink_compat.c:1107 [inline]
  26  tipc_nl_compat_recv+0x14d7/0x2760 net/tipc/netlink_compat.c:1210
  27  genl_family_rcv_msg net/netlink/genetlink.c:601 [inline]
  28  genl_rcv_msg+0x185f/0x1a60 net/netlink/genetlink.c:626
  29  netlink_rcv_skb+0x444/0x640 net/netlink/af_netlink.c:2477
  30  genl_rcv+0x63/0x80 net/netlink/genetlink.c:637
  31  netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
  32  netlink_unicast+0xf40/0x1020 net/netlink/af_netlink.c:1336
  33  netlink_sendmsg+0x127f/0x1300 net/netlink/af_netlink.c:1917
  34  sock_sendmsg_nosec net/socket.c:621 [inline]
  35  sock_sendmsg net/socket.c:631 [inline]
  36  ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2116
  37  __sys_sendmsg net/socket.c:2154 [inline]
  38  __do_sys_sendmsg net/socket.c:2163 [inline]
  39  __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
  40  __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
  41  do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
  42  entry_SYSCALL_64_after_hwframe+0x63/0xe7
  43 RIP: 0033:0x457ec9
  44 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
  45 RSP: 002b:00007f2557338c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
  46 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9
  47 RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
  48 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
  49 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f25573396d4
  50 R13: 00000000004cb478 R14: 00000000004d86c8 R15: 00000000ffffffff
  51
  52 Uninit was created at:
  53  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline]
  54  kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158
  55  kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176
  56  kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185
  57  slab_post_alloc_hook mm/slab.h:446 [inline]
  58  slab_alloc_node mm/slub.c:2759 [inline]
  59  __kmalloc_node_track_caller+0xe18/0x1030 mm/slub.c:4383
  60  __kmalloc_reserve net/core/skbuff.c:137 [inline]
  61  __alloc_skb+0x309/0xa20 net/core/skbuff.c:205
  62  alloc_skb include/linux/skbuff.h:998 [inline]
  63  netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
  64  netlink_sendmsg+0xb82/0x1300 net/netlink/af_netlink.c:1892
  65  sock_sendmsg_nosec net/socket.c:621 [inline]
  66  sock_sendmsg net/socket.c:631 [inline]
  67  ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2116
  68  __sys_sendmsg net/socket.c:2154 [inline]
  69  __do_sys_sendmsg net/socket.c:2163 [inline]
  70  __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
  71  __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
  72  do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
  73  entry_SYSCALL_64_after_hwframe+0x63/0xe7
  74
  75 The uninitialised access happened in tipc_nl_compat_link_reset_stats:
  76     nla_put_string(skb, TIPC_NLA_LINK_NAME, name)
  77
  78 This is because name string is not validated before it's used.
  79
  80 Reported-by: syzbot+e01d94b5a4c266be6e4c@syzkaller.appspotmail.com
  81 Signed-off-by: Ying Xue <ying.xue@windriver.com>
  82 Signed-off-by: David S. Miller <davem@davemloft.net>
  83 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  84
  85 ---
  86  net/tipc/netlink_compat.c |   15 +++++++++++++++
  87  1 file changed, 15 insertions(+)
  88
  89 --- a/net/tipc/netlink_compat.c
  90 +++ b/net/tipc/netlink_compat.c
  91 @@ -87,6 +87,11 @@ static int tipc_skb_tailroom(struct sk_b
  92         return limit;
  93  }
  94
  95 +static inline int TLV_GET_DATA_LEN(struct tlv_desc *tlv)
  96 +{
  97 +       return TLV_GET_LEN(tlv) - TLV_SPACE(0);
  98 +}
  99 +
 100  static int tipc_add_tlv(struct sk_buff *skb, u16 type, void *data, u16 len)
 101  {
 102         struct tlv_desc *tlv = (struct tlv_desc *)skb_tail_pointer(skb);
 103 @@ -166,6 +171,11 @@ static struct sk_buff *tipc_get_err_tlv(
 104         return buf;
 105  }
 106
 107 +static inline bool string_is_valid(char *s, int len)
 108 +{
 109 +       return memchr(s, '\0', len) ? true : false;
 110 +}
 111 +
 112  static int __tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
 113                                    struct tipc_nl_compat_msg *msg,
 114                                    struct sk_buff *arg)
 115 @@ -711,6 +721,7 @@ static int tipc_nl_compat_link_reset_sta
 116  {
 117         char *name;
 118         struct nlattr *link;
 119 +       int len;
 120
 121         name = (char *)TLV_DATA(msg->req);
 122
 123 @@ -718,6 +729,10 @@ static int tipc_nl_compat_link_reset_sta
 124         if (!link)
 125                 return -EMSGSIZE;
 126
 127 +       len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_LINK_NAME);
 128 +       if (!string_is_valid(name, len))
 129 +               return -EINVAL;
 130 +
 131         if (nla_put_string(skb, TIPC_NLA_LINK_NAME, name))
 132                 return -EMSGSIZE;
 133