lkml.org 
[lkml]   [2019]   [May]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.4 071/266] tipc: check bearer name with right length in tipc_nl_compat_bearer_enable
    Date
    From: Xin Long <lucien.xin@gmail.com>

    commit 6f07e5f06c8712acc423485f657799fc8e11e56c upstream.

    Syzbot reported the following crash:

    BUG: KMSAN: uninit-value in memchr+0xce/0x110 lib/string.c:961
    memchr+0xce/0x110 lib/string.c:961
    string_is_valid net/tipc/netlink_compat.c:176 [inline]
    tipc_nl_compat_bearer_enable+0x2c4/0x910 net/tipc/netlink_compat.c:401
    __tipc_nl_compat_doit net/tipc/netlink_compat.c:321 [inline]
    tipc_nl_compat_doit+0x3aa/0xaf0 net/tipc/netlink_compat.c:354
    tipc_nl_compat_handle net/tipc/netlink_compat.c:1162 [inline]
    tipc_nl_compat_recv+0x1ae7/0x2750 net/tipc/netlink_compat.c:1265
    genl_family_rcv_msg net/netlink/genetlink.c:601 [inline]
    genl_rcv_msg+0x185f/0x1a60 net/netlink/genetlink.c:626
    netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477
    genl_rcv+0x63/0x80 net/netlink/genetlink.c:637
    netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
    netlink_unicast+0xf3e/0x1020 net/netlink/af_netlink.c:1336
    netlink_sendmsg+0x127f/0x1300 net/netlink/af_netlink.c:1917
    sock_sendmsg_nosec net/socket.c:622 [inline]
    sock_sendmsg net/socket.c:632 [inline]

    Uninit was created at:
    __alloc_skb+0x309/0xa20 net/core/skbuff.c:208
    alloc_skb include/linux/skbuff.h:1012 [inline]
    netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
    netlink_sendmsg+0xb82/0x1300 net/netlink/af_netlink.c:1892
    sock_sendmsg_nosec net/socket.c:622 [inline]
    sock_sendmsg net/socket.c:632 [inline]

    It was triggered when the bearer name size < TIPC_MAX_BEARER_NAME,
    it would check with a wrong len/TLV_GET_DATA_LEN(msg->req), which
    also includes priority and disc_domain length.

    This patch is to fix it by checking it with a right length:
    'TLV_GET_DATA_LEN(msg->req) - offsetof(struct tipc_bearer_config, name)'.

    Reported-by: syzbot+8b707430713eb46e1e45@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/tipc/netlink_compat.c | 7 ++++++-
    1 file changed, 6 insertions(+), 1 deletion(-)

    --- a/net/tipc/netlink_compat.c
    +++ b/net/tipc/netlink_compat.c
    @@ -388,7 +388,12 @@ static int tipc_nl_compat_bearer_enable(
    if (!bearer)
    return -EMSGSIZE;

    - len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME);
    + len = TLV_GET_DATA_LEN(msg->req);
    + len -= offsetof(struct tipc_bearer_config, name);
    + if (len <= 0)
    + return -EINVAL;
    +
    + len = min_t(int, len, TIPC_MAX_BEARER_NAME);
    if (!string_is_valid(b->name, len))
    return -EINVAL;


    \
     
     \ /
      Last update: 2019-05-15 13:06    [W:4.098 / U:0.132 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site