lkml.org 
[lkml]   [2019]   [Apr]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 020/101] sctp: initialize _pad of sockaddr_in before copying to user memory
    Date
    [ Upstream commit 09279e615c81ce55e04835970601ae286e3facbe ]

    Syzbot report a kernel-infoleak:

    BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
    Call Trace:
    _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
    copy_to_user include/linux/uaccess.h:174 [inline]
    sctp_getsockopt_peer_addrs net/sctp/socket.c:5911 [inline]
    sctp_getsockopt+0x1668e/0x17f70 net/sctp/socket.c:7562
    ...
    Uninit was stored to memory at:
    sctp_transport_init net/sctp/transport.c:61 [inline]
    sctp_transport_new+0x16d/0x9a0 net/sctp/transport.c:115
    sctp_assoc_add_peer+0x532/0x1f70 net/sctp/associola.c:637
    sctp_process_param net/sctp/sm_make_chunk.c:2548 [inline]
    sctp_process_init+0x1a1b/0x3ed0 net/sctp/sm_make_chunk.c:2361
    ...
    Bytes 8-15 of 16 are uninitialized

    It was caused by that th _pad field (the 8-15 bytes) of a v4 addr (saved in
    struct sockaddr_in) wasn't initialized, but directly copied to user memory
    in sctp_getsockopt_peer_addrs().

    So fix it by calling memset(addr->v4.sin_zero, 0, 8) to initialize _pad of
    sockaddr_in before copying it to user memory in sctp_v4_addr_to_user(), as
    sctp_v6_addr_to_user() does.

    Reported-by: syzbot+86b5c7c236a22616a72f@syzkaller.appspotmail.com
    Signed-off-by: Xin Long <lucien.xin@gmail.com>
    Tested-by: Alexander Potapenko <glider@google.com>
    Acked-by: Neil Horman <nhorman@tuxdriver.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/sctp/protocol.c | 1 +
    1 file changed, 1 insertion(+)

    diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
    index 1c9f079e8a50..d97b2b4b7a8b 100644
    --- a/net/sctp/protocol.c
    +++ b/net/sctp/protocol.c
    @@ -600,6 +600,7 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
    static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
    {
    /* No address mapping for V4 sockets */
    + memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
    return sizeof(struct sockaddr_in);
    }

    --
    2.19.1


    \
     
     \ /
      Last update: 2019-04-15 21:07    [W:2.783 / U:0.232 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site