102 lines
3.4 KiB
C
102 lines
3.4 KiB
C
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/*
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* Copyright © 2017 Broadcom
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is 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 (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* 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
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <poll.h>
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#include <xcb/xcb.h>
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#include <xcb/bigreq.h>
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#include <xcb/xinput.h>
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int main(int argc, char **argv)
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{
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xcb_connection_t *c = xcb_connect(NULL, NULL);
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int fd = xcb_get_file_descriptor(c);
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struct {
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uint8_t extension;
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uint8_t opcode;
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uint16_t length;
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uint32_t length_bigreq;
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uint32_t win;
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int num_masks;
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uint16_t pad;
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} xise_req = {
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.extension = 0,
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.opcode = XCB_INPUT_XI_SELECT_EVENTS,
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/* The server triggers BadValue on a zero num_mask */
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.num_masks = 0,
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.win = 0,
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/* This is the value that triggers the bug. */
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.length_bigreq = 0,
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};
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xcb_query_extension_cookie_t cookie;
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xcb_query_extension_reply_t *rep;
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cookie = xcb_query_extension(c, 15, "XInputExtension");
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rep = xcb_query_extension_reply(c, cookie, NULL);
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xise_req.extension = rep->major_opcode;
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free(xcb_big_requests_enable_reply(c, xcb_big_requests_enable(c), NULL));
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/* Manually write out the bad request. XCB can't help us here.*/
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write(fd, &xise_req, sizeof(xise_req));
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/* Block until the server has processed our mess and throws an
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* error. If we get disconnected, then the server has noticed what we're
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* up to. If we get an error back from the server, it looked at our fake
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* request - which shouldn't happen.
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*/
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struct pollfd pfd = {
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.fd = fd,
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.events = POLLIN,
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};
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poll(&pfd, 1, -1);
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if (pfd.revents & POLLHUP) {
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/* We got killed by the server for being naughty. Yay! */
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return 0;
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}
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/* We didn't get disconnected, that's bad. If we get a BadValue from our
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* request, we at least know that the bug triggered.
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*
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* If we get anything else back, something else has gone wrong.
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*/
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xcb_generic_error_t error;
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int r = read(fd, &error, sizeof(error));
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if (r == sizeof(error) &&
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error.error_code == 2 /* BadValue */ &&
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error.major_code == xise_req.extension &&
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error.minor_code == XCB_INPUT_XI_SELECT_EVENTS)
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return 1; /* Our request was processed, which shouldn't happen */
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/* Something else bad happened. We got something back but it's not the
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* error we expected. If this happens, it needs to be investigated. */
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return 2;
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}
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