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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>
155 lines
4.5 KiB
C
155 lines
4.5 KiB
C
/*
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* QEMU VNC display driver: zlib encoding
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*
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* Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
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* Copyright (C) 2006 Fabrice Bellard
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* Copyright (C) 2009 Red Hat, Inc
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "vnc.h"
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#define ZALLOC_ALIGNMENT 16
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void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size)
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{
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void *p;
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size *= items;
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size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);
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p = g_malloc0(size);
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return (p);
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}
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void vnc_zlib_zfree(void *x, void *addr)
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{
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g_free(addr);
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}
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static void vnc_zlib_start(VncState *vs)
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{
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buffer_reset(&vs->zlib.zlib);
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// make the output buffer be the zlib buffer, so we can compress it later
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vs->zlib.tmp = vs->output;
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vs->output = vs->zlib.zlib;
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}
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static int vnc_zlib_stop(VncState *vs)
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{
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z_streamp zstream = &vs->zlib.stream;
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int previous_out;
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// switch back to normal output/zlib buffers
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vs->zlib.zlib = vs->output;
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vs->output = vs->zlib.tmp;
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// compress the zlib buffer
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// initialize the stream
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// XXX need one stream per session
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if (zstream->opaque != vs) {
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int err;
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VNC_DEBUG("VNC: initializing zlib stream\n");
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VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
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zstream->zalloc = vnc_zlib_zalloc;
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zstream->zfree = vnc_zlib_zfree;
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err = deflateInit2(zstream, vs->tight->compression, Z_DEFLATED,
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MAX_WBITS,
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MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
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if (err != Z_OK) {
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fprintf(stderr, "VNC: error initializing zlib\n");
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return -1;
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}
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vs->zlib.level = vs->tight->compression;
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zstream->opaque = vs;
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}
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if (vs->tight->compression != vs->zlib.level) {
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if (deflateParams(zstream, vs->tight->compression,
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Z_DEFAULT_STRATEGY) != Z_OK) {
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return -1;
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}
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vs->zlib.level = vs->tight->compression;
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}
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// reserve memory in output buffer
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buffer_reserve(&vs->output, vs->zlib.zlib.offset + 64);
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// set pointers
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zstream->next_in = vs->zlib.zlib.buffer;
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zstream->avail_in = vs->zlib.zlib.offset;
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zstream->next_out = vs->output.buffer + vs->output.offset;
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zstream->avail_out = vs->output.capacity - vs->output.offset;
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previous_out = zstream->avail_out;
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zstream->data_type = Z_BINARY;
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// start encoding
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if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
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fprintf(stderr, "VNC: error during zlib compression\n");
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return -1;
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}
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vs->output.offset = vs->output.capacity - zstream->avail_out;
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return previous_out - zstream->avail_out;
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}
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int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
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{
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int old_offset, new_offset, bytes_written;
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vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_ZLIB);
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// remember where we put in the follow-up size
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old_offset = vs->output.offset;
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vnc_write_s32(vs, 0);
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// compress the stream
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vnc_zlib_start(vs);
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vnc_raw_send_framebuffer_update(vs, x, y, w, h);
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bytes_written = vnc_zlib_stop(vs);
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if (bytes_written == -1)
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return 0;
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// hack in the size
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new_offset = vs->output.offset;
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vs->output.offset = old_offset;
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vnc_write_u32(vs, bytes_written);
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vs->output.offset = new_offset;
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return 1;
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}
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void vnc_zlib_clear(VncState *vs)
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{
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if (vs->zlib.stream.opaque) {
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deflateEnd(&vs->zlib.stream);
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}
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buffer_free(&vs->zlib.zlib);
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}
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