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cherry-pick a bugfix #18

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merged 1 commit into from Mar 31, 2018
Merged

cherry-pick a bugfix #18

merged 1 commit into from Mar 31, 2018

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vcunat
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@vcunat vcunat commented Mar 30, 2018

It hasn't been picked upstream to systemd-stable yet, but it seems simple enough. I tried several nixos tests atop current 18.03. /cc @fpletz NixOS/nixpkgs#37744

If a device exposes more than 16 mouse buttons, we run into the BTN_JOYSTICK
range, also labelling it as joystick. And since 774ff9b this results in only
ID_INPUT_JOYSTICK but no ID_INPUT_MOUSE.

Fixes systemd#8460

(cherry picked from commit 0cd6767)
See also NixOS/nixpkgs#37744
@shlevy shlevy merged commit 82ca096 into NixOS:nixos-v238 Mar 31, 2018
@vcunat vcunat deleted the nixos-v238 branch March 31, 2018 13:24
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vcunat commented Mar 31, 2018

Hmm, I didn't push it to nixpkgs yet, due to another systemd-related regression NixOS/nixpkgs@6b9771e4

fpletz pushed a commit that referenced this pull request Aug 3, 2018
Fuzzing with AddressSanitizer reports an error here:
==11==ERROR: AddressSanitizer: global-buffer-overflow on address 0x7fe53f5497d8 at pc 0x7fe53ef055c9 bp 0x7ffd344e9380 sp 0x7ffd344e9378
READ of size 4 at 0x7fe53f5497d8 thread T0
SCARINESS: 27 (4-byte-read-global-buffer-overflow-far-from-bounds)
    #0 0x7fe53ef055c8 in bus_error_name_to_errno /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-error.c:118:24
    #1 0x7fe53ef0577b in bus_error_setfv /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-error.c:274:17
    #2 0x7fe53ef0595a in sd_bus_error_setf /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-error.c:284:21
    #3 0x561059 in manager_load_unit_prepare /work/build/../../src/systemd/src/core/manager.c
    #4 0x560680 in manager_load_unit /work/build/../../src/systemd/src/core/manager.c:1773:13
    #5 0x5d49a6 in unit_add_dependency_by_name /work/build/../../src/systemd/src/core/unit.c:2882:13
    #6 0x538996 in config_parse_unit_deps /work/build/../../src/systemd/src/core/load-fragment.c:152:21
    #7 0x6db771 in next_assignment /work/build/../../src/systemd/src/shared/conf-parser.c:155:32
    #8 0x6d697e in parse_line /work/build/../../src/systemd/src/shared/conf-parser.c:273:16
    #9 0x6d5c48 in config_parse /work/build/../../src/systemd/src/shared/conf-parser.c:390:21
    #10 0x535678 in LLVMFuzzerTestOneInput /work/build/../../src/systemd/src/fuzz/fuzz-unit-file.c:41:16
    #11 0x73bd60 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/libfuzzer/FuzzerLoop.cpp:517:13
    #12 0x73a39f in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) /src/libfuzzer/FuzzerLoop.cpp:442:3
    #13 0x73d9bc in fuzzer::Fuzzer::MutateAndTestOne() /src/libfuzzer/FuzzerLoop.cpp:650:19
    #14 0x73fa05 in fuzzer::Fuzzer::Loop(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, fuzzer::fuzzer_allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&) /src/libfuzzer/FuzzerLoop.cpp:773:5
    #15 0x71f75d in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/libfuzzer/FuzzerDriver.cpp:754:6
    #16 0x71285c in main /src/libfuzzer/FuzzerMain.cpp:20:10
    #17 0x7fe53da0482f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #18 0x430e68 in _start (/out/fuzz-unit-file+0x430e68)

0x7fe53f5497d8 is located 8 bytes to the right of global variable 'bus_common_errors' defined in '../../src/systemd/src/libsystemd/sd-bus/bus-common-errors.c:28:51' (0x7fe53f549300) of size 1232
SUMMARY: AddressSanitizer: global-buffer-overflow /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-error.c:118:24 in bus_error_name_to_errno
Shadow bytes around the buggy address:
  0x0ffd27ea12a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ffd27ea12b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ffd27ea12c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ffd27ea12d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ffd27ea12e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0ffd27ea12f0: 00 00 00 00 00 00 00 00 00 00 f9[f9]f9 f9 f9 f9
  0x0ffd27ea1300: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  0x0ffd27ea1310: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  0x0ffd27ea1320: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ffd27ea1330: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ffd27ea1340: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==11==ABORTING

but I think it's a false positive because of our low-level magic in how this
area is constructed.
Mic92 pushed a commit that referenced this pull request Feb 22, 2019
This function returns 0 on success and a negative value on failure. On success,
it writes the parsed action to the address passed in its third argument.

`bus_set_transient_emergency_action` does this:

 r = parse_emergency_action(s, system, &v);
 if (v < 0)
     // handle failure

However, `v` is not updated if the function fails, and this should be checking
`r` instead of `v`.

The result of this is that if an invalid failure (or success) action is
specified, systemd ends up creating the unit anyway and then misbehaves if it
tries to run the failure action because the action value comes from
uninitialized stack data. In my case, this resulted in a failed assertion:

 Program received signal SIGABRT, Aborted.
 0x00007fe52cca0d7f in raise () from /snap/usr/lib/libc.so.6
 (gdb) bt
 #0  0x00007fe52cca0d7f in raise () from /snap/usr/lib/libc.so.6
 #1  0x00007fe52cc8b672 in abort () from /snap/usr/lib/libc.so.6
 #2  0x00007fe52d66f169 in log_assert_failed_realm (realm=LOG_REALM_SYSTEMD, text=0x56177ab8e000 "action < _EMERGENCY_ACTION_MAX", file=0x56177ab8dfb8 "../src/core/emergency-action.c", line=33, func=0x56177ab8e2b0 <__PRETTY_FUNCTION__.14207> "emergency_action") at ../src/basic/log.c:795
 #3  0x000056177aa98cf4 in emergency_action (m=0x56177c992cb0, action=2059118610, options=(unknown: 0), reboot_arg=0x0, exit_status=1, reason=0x7ffdd2df4290 "unit run-u0.service failed") at ../src/core/emergency-action.c:33
 #4  0x000056177ab2b739 in unit_notify (u=0x56177c9eb340, os=UNIT_ACTIVE, ns=UNIT_FAILED, flags=(unknown: 0)) at ../src/core/unit.c:2504
 #5  0x000056177aaf62ed in service_set_state (s=0x56177c9eb340, state=SERVICE_FAILED) at ../src/core/service.c:1104
 #6  0x000056177aaf8a29 in service_enter_dead (s=0x56177c9eb340, f=SERVICE_SUCCESS, allow_restart=true) at ../src/core/service.c:1712
 #7  0x000056177aaf9233 in service_enter_signal (s=0x56177c9eb340, state=SERVICE_FINAL_SIGKILL, f=SERVICE_SUCCESS) at ../src/core/service.c:1854
 #8  0x000056177aaf921b in service_enter_signal (s=0x56177c9eb340, state=SERVICE_FINAL_SIGTERM, f=SERVICE_SUCCESS) at ../src/core/service.c:1852
 #9  0x000056177aaf8eb3 in service_enter_stop_post (s=0x56177c9eb340, f=SERVICE_SUCCESS) at ../src/core/service.c:1788
 #10 0x000056177aaf91eb in service_enter_signal (s=0x56177c9eb340, state=SERVICE_STOP_SIGKILL, f=SERVICE_SUCCESS) at ../src/core/service.c:1850
 #11 0x000056177aaf91bc in service_enter_signal (s=0x56177c9eb340, state=SERVICE_STOP_SIGTERM, f=SERVICE_FAILURE_EXIT_CODE) at ../src/core/service.c:1848
 #12 0x000056177aaf9759 in service_enter_running (s=0x56177c9eb340, f=SERVICE_FAILURE_EXIT_CODE) at ../src/core/service.c:1941
 #13 0x000056177ab005b7 in service_sigchld_event (u=0x56177c9eb340, pid=112, code=1, status=1) at ../src/core/service.c:3296
 #14 0x000056177aad84b5 in manager_invoke_sigchld_event (m=0x56177c992cb0, u=0x56177c9eb340, si=0x7ffdd2df48f0) at ../src/core/manager.c:2444
 #15 0x000056177aad88df in manager_dispatch_sigchld (source=0x56177c994710, userdata=0x56177c992cb0) at ../src/core/manager.c:2508
 #16 0x00007fe52d72f807 in source_dispatch (s=0x56177c994710) at ../src/libsystemd/sd-event/sd-event.c:2846
 #17 0x00007fe52d730f7d in sd_event_dispatch (e=0x56177c993530) at ../src/libsystemd/sd-event/sd-event.c:3229
 #18 0x00007fe52d73142e in sd_event_run (e=0x56177c993530, timeout=18446744073709551615) at ../src/libsystemd/sd-event/sd-event.c:3286
 #19 0x000056177aad9f71 in manager_loop (m=0x56177c992cb0) at ../src/core/manager.c:2906
 #20 0x000056177aa7c876 in invoke_main_loop (m=0x56177c992cb0, ret_reexecute=0x7ffdd2df4bff, ret_retval=0x7ffdd2df4c04, ret_shutdown_verb=0x7ffdd2df4c58, ret_fds=0x7ffdd2df4c70, ret_switch_root_dir=0x7ffdd2df4c48, ret_switch_root_init=0x7ffdd2df4c50, ret_error_message=0x7ffdd2df4c60) at ../src/core/main.c:1792
 #21 0x000056177aa7f251 in main (argc=2, argv=0x7ffdd2df4e78) at ../src/core/main.c:2573

Fix this by checking the correct variable.
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