glibc/sysdeps/unix/sysv/linux/tst-personality.c
Adhemerval Zanella d4963a844d linux: Fail as unsupported if personality call is filtered
Container management default seccomp filter [1] only accepts
personality(2) with PER_LINUX, (0x0), UNAME26 (0x20000),
PER_LINUX32 (0x8), UNAME26 | PER_LINUX32, and 0xffffffff (to query
current personality)

Although the documentation only state it is blocked to prevent
'enabling BSD emulation' (PER_BSD, not implemented by Linux), checking
on repository log the real reason is to block ASLR disable flag
(ADDR_NO_RANDOMIZE) and other poorly support emulations.

So handle EPERM and fail as UNSUPPORTED if we can really check for
BZ#19408.

Checked on aarch64-linux-gnu.

[1] https://github.com/moby/moby/blob/master/profiles/seccomp/default.json

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-06-05 12:51:48 -03:00

55 lines
1.7 KiB
C

/* BZ #19408 linux personality syscall wrapper test.
Copyright (C) 2015-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <sys/personality.h>
#include <support/check.h>
static int
do_test (void)
{
unsigned int test_persona = -EINVAL;
unsigned int saved_persona;
errno = 0xdefaced;
saved_persona = personality (0xffffffff);
unsigned int r = personality (test_persona);
if (r == -1)
{
/* The syscall argument might be filtered by kernel, so the
test can not check for the bug issue. */
if (errno == EPERM)
FAIL_UNSUPPORTED ("personality syscall argument are filtered");
FAIL_EXIT1 ("personality (%#x) failed: %m", test_persona);
}
TEST_COMPARE (r, saved_persona);
TEST_VERIFY (personality (0xffffffff) != -1);
TEST_VERIFY (personality (PER_LINUX) != -1);
TEST_COMPARE (personality (0xffffffff), PER_LINUX);
TEST_COMPARE (0xdefaced, errno);
personality (saved_persona);
return 0;
}
#include <support/test-driver.c>