wob crashes when an empty string is echoed to fifo about wob

[francma]

I just tested it and wob exits due to invalid input - which is intended behavior. Are you sure that it crashes and not exists?

What is written to stderr? Something like this?

ERROR main.c:851: Received invalid input

[l3s2d]

I ran echo "" > $XDG_RUNTIME_DIR/wob.sock, and this is the journald output I'm seeing:

Found module linux-vdso.so.1 with build-id: e03e20cb310dd7f3aa2cff60ad39737026d9ebe6
Found module ld-linux-x86-64.so.2 with build-id: 040cc3dd10461562f177df39e3be2f3704258c3c
Found module libpthread.so.0 with build-id: 07c8f95b4f3251d08550217ad8a1f31066229996
Found module libffi.so.8 with build-id: f90d8b734f6de9b25faedb8cbfab7054dafc0a42
Found module libc.so.6 with build-id: 4b406737057708c0e4c642345a703c47a61c73dc
Found module libseccomp.so.2 with build-id: 54179323d84e1b713b7547ba0b3f8310e65eec93
Found module librt.so.1 with build-id: 75484da2d6f1515189eefa076e0a40328834cd16
Found module libwayland-client.so.0 with build-id: 0a237f2fd096bada4ca381eec5d64474c4078be4
Found module wob with build-id: 8b650646d60663e7687768042e18e0e67c5c9a78
Stack trace of thread 109914:
#0  0x00007f2baf27699b llseek@GLIBC_2.2.5 (libc.so.6 + 0xef99b)
#1  0x00007f2baf206b3e _IO_file_sync@@GLIBC_2.2.5 (libc.so.6 + 0x7fb3e)
#2  0x00007f2baf20a105 _IO_default_setbuf (libc.so.6 + 0x83105)
#3  0x00007f2baf206c3d _IO_file_setbuf@@GLIBC_2.2.5 (libc.so.6 + 0x7fc3d)
#4  0x00007f2baf20ab3c _IO_cleanup (libc.so.6 + 0x83b3c)
#5  0x00007f2baf1c65a2 __run_exit_handlers (libc.so.6 + 0x3f5a2)
#6  0x00007f2baf1c664e exit (libc.so.6 + 0x3f64e)
#7  0x00007f2baf1aeb2c __libc_start_main (libc.so.6 + 0x27b2c)
#8  0x000055b49a749c4e n/a (wob + 0x4c4e)

[francma]

Could you please post output of:

WOB_DISABLE_PLEDGE=1 strace wob

There is a problem with seccomp sandbox (syscall whitelist) and this will tell me which syscall needs to be allowed. From stackttace it looks like lseek, but better to be sure.

[l3s2d]

It seems like this only happens when running as a systemd service. Otherwise wob exits with the message you posted above. Setting that envvar does make it so wob doesn't crash (still exits), but the strace output with the envvar set and unset is identical:

restart_syscall(<... resuming interrupted read ...>) = 1
read(0, "\n", 56)                       = 1
write(2, "1640734637.522840 ERROR main.c:8"..., 36) = 36
write(2, "Received invalid input", 22)  = 22
write(2, "\n", 1)                       = 1
close(5)                                = 0
close(4)                                = 0
exit_group(1)                           = ?

I used strace -p to attach to the process started by systemd, I'm not sure how else to strace the systemd service.

[francma]

Could you please try it again with latest master (wob-git)? Hopefully fixed in this commit 1b0ad80.

[l3s2d]

I have confirmed that wob-git does not crash. Thank you for fixing this!