Re: [libvirt] [PATCH] tests: Add getuid() to virnetdevbandwidthmock

On Mon, Jul 08, 2019 at 06:03:10PM +0200, Andrea Bolognani wrote: > When only geteuid() is mocked, the test crashes on Debian 10. > > Fatal: failed to reset uid: No such file or directory > > Program received signal SIGABRT, Aborted. > __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50 > 50 ../sysdeps/unix/sysv/linux/raise.c: No such file or directory. > (gdb) t a a bt > > Thread 1 (Thread 0x7ffff3b3e080 (LWP 12003)): > #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50 > #1 0x00007ffff7798535 in __GI_abort () at abort.c:79 > #2 0x00007ffff485ca20 in _gcry_logv (level=level@entry=40, fmt=fmt@entry=0x7ffff4929126 "failed to reset uid: %s\n", arg_ptr=arg_ptr@entry=0x7fffffffe4a0) at ../../src/misc.c:142 > #3 0x00007ffff485cd61 in _gcry_log_fatal (fmt=fmt@entry=0x7ffff4929126 "failed to reset uid: %s\n") at ../../src/misc.c:218 > #4 0x00007ffff48639d1 in lock_pool_pages (n=<optimized out>, p=<optimized out>) at ../../src/secmem.c:340 > #5 _gcry_secmem_init_internal (n=<optimized out>) at ../../src/secmem.c:563 > #6 0x00007ffff4863d78 in _gcry_secmem_init (n=4096) at ../../src/secmem.c:581 > #7 0x00007ffff485e4e6 in _gcry_vcontrol (cmd=<optimized out>, arg_ptr=arg_ptr@entry=0x7fffffffe5e0) at ../../src/global.c:506 > #8 0x00007ffff485a789 in gcry_control (cmd=cmd@entry=GCRYCTL_INIT_SECMEM) at ../../src/visibility.c:79 > #9 0x00007ffff71af10f in ssh_crypto_init () at ./src/libgcrypt.c:621 > #10 0x00007ffff7193796 in _ssh_init (constructor=constructor@entry=1) at ./src/init.c:79 > #11 0x00007ffff71834de in libssh_constructor () at ./src/init.c:116 Ewww, so its crashing in a ELF library constructor for libssh, which is in turn calling into libgcrypt. Obviously nothing todo with the test cases we're actually running. I guess we're confusing the code into thinking it has some wierd privilege by having geteuid() return 0, while getuid() returns the normal UID. Mocking getuid() is ok, but I fear its just a targetting one specific problem we happen to be hitting today. So I think we probably ought to make geteuid() delegate the real getuid() function instead. Have a global flag we can set & unset just before & after executing the real test code. That way libraries will see correct UID info in general.