Given the following code containing errors, provide Common Weakness Enumeration (CWE) identifiers and corresponding messages in JSON format. Each identified weakness should have a unique entry in the JSON array.
    Code: static int send_palette_rect(VncState *vs, int x, int y,
                             int w, int h, VncPalette *palette)
{
    int stream = 2;
    int level = tight_conf[vs->tight.compression].idx_zlib_level;
    int colors;
    ssize_t bytes;

#ifdef CONFIG_VNC_PNG
    if (tight_can_send_png_rect(vs, w, h)) {
        return send_png_rect(vs, x, y, w, h, palette);
    }
#endif

    colors = palette_size(palette);

    vnc_write_u8(vs, (stream | VNC_TIGHT_EXPLICIT_FILTER) << 4);
    vnc_write_u8(vs, VNC_TIGHT_FILTER_PALETTE);
    vnc_write_u8(vs, colors - 1);

    switch (vs->client_pf.bytes_per_pixel) {
    case 4:
    {
        size_t old_offset, offset;
        uint32_t header[palette_size(palette)];
        struct palette_cb_priv priv = { vs, (uint8_t *)header };

        old_offset = vs->output.offset;
        palette_iter(palette, write_palette, &priv);
        vnc_write(vs, header, sizeof(header));

        if (vs->tight.pixel24) {
            tight_pack24(vs, vs->output.buffer + old_offset, colors, &offset);
            vs->output.offset = old_offset + offset;
        }

        tight_encode_indexed_rect32(vs->tight.tight.buffer, w * h, palette);
        break;
    }
    case 2:
    {
        uint16_t header[palette_size(palette)];
        struct palette_cb_priv priv = { vs, (uint8_t *)header };

        palette_iter(palette, write_palette, &priv);
        vnc_write(vs, header, sizeof(header));
        tight_encode_indexed_rect16(vs->tight.tight.buffer, w * h, palette);
        break;
    }
    default:
        return -1; /* No palette for 8bits colors */
        break;
    }
    bytes = w * h;
    vs->tight.tight.offset = bytes;

    bytes = tight_compress_data(vs, stream, bytes,
                                level, Z_DEFAULT_STRATEGY);
    return (bytes >= 0);
} ; Sample JSON Format Confermily Expected output: "examples" => "cwe": "xxx"; "message": "xxx"
    
 'cwe': ['CWE-401'], 'message': 'vnc: fix memory leak when vnc disconnect

Currently when qemu receives a vnc connect, it creates a 'VncState' to
represent this connection. In 'vnc_worker_thread_loop' it creates a
local 'VncState'. The connection 'VcnState' and local 'VncState' exchange
data in 'vnc_async_encoding_start' and 'vnc_async_encoding_end'.
In 'zrle_compress_data' it calls 'deflateInit2' to allocate the libz library
opaque data. The 'VncState' used in 'zrle_compress_data' is the local
'VncState'. In 'vnc_zrle_clear' it calls 'deflateEnd' to free the libz
library opaque data. The 'VncState' used in 'vnc_zrle_clear' is the connection
'VncState'. In currently implementation there will be a memory leak when the
vnc disconnect. Following is the asan output backtrack:

Direct leak of 29760 byte(s) in 5 object(s) allocated from:
    0 0xffffa67ef3c3 in __interceptor_calloc (/lib64/libasan.so.4+0xd33c3)
    1 0xffffa65071cb in g_malloc0 (/lib64/libglib-2.0.so.0+0x571cb)
    2 0xffffa5e968f7 in deflateInit2_ (/lib64/libz.so.1+0x78f7)
    3 0xaaaacec58613 in zrle_compress_data ui/vnc-enc-zrle.c:87
    4 0xaaaacec58613 in zrle_send_framebuffer_update ui/vnc-enc-zrle.c:344
    5 0xaaaacec34e77 in vnc_send_framebuffer_update ui/vnc.c:919
    6 0xaaaacec5e023 in vnc_worker_thread_loop ui/vnc-jobs.c:271
    7 0xaaaacec5e5e7 in vnc_worker_thread ui/vnc-jobs.c:340
    8 0xaaaacee4d3c3 in qemu_thread_start util/qemu-thread-posix.c:502
    9 0xffffa544e8bb in start_thread (/lib64/libpthread.so.0+0x78bb)
    10 0xffffa53965cb in thread_start (/lib64/libc.so.6+0xd55cb)

This is because the opaque allocated in 'deflateInit2' is not freed in
'deflateEnd'. The reason is that the 'deflateEnd' calls 'deflateStateCheck'
and in the latter will check whether 's->strm != strm'(libz's data structure).
This check will be true so in 'deflateEnd' it just return 'Z_STREAM_ERROR' and
not free the data allocated in 'deflateInit2'.

The reason this happens is that the 'VncState' contains the whole 'VncZrle',
so when calling 'deflateInit2', the 's->strm' will be the local address.
So 's->strm != strm' will be true.

To fix this issue, we need to make 'zrle' of 'VncState' to be a pointer.
Then the connection 'VncState' and local 'VncState' exchange mechanism will
work as expection. The 'tight' of 'VncState' has the same issue, let's also turn
it to a pointer.

Reported-by: Ying Fang <fangying1@huawei.com>
Signed-off-by: Li Qiang <liq3ea@163.com>
Message-id: 20190831153922.121308-1-liq3ea@163.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>'