From d4963a844dc72c4ac14da3395cf511f3d191d689 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Fri, 2 Jun 2023 10:19:48 -0300 Subject: [PATCH] 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 --- sysdeps/unix/sysv/linux/tst-personality.c | 33 ++++++++++++++--------- 1 file changed, 21 insertions(+), 12 deletions(-) diff --git a/sysdeps/unix/sysv/linux/tst-personality.c b/sysdeps/unix/sysv/linux/tst-personality.c index e730650e5b..5e59627826 100644 --- a/sysdeps/unix/sysv/linux/tst-personality.c +++ b/sysdeps/unix/sysv/linux/tst-personality.c @@ -19,27 +19,36 @@ #include #include +#include static int do_test (void) { - int rc = 0; unsigned int test_persona = -EINVAL; unsigned int saved_persona; errno = 0xdefaced; saved_persona = personality (0xffffffff); - if (personality (test_persona) != saved_persona - || personality (0xffffffff) == -1 - || personality (PER_LINUX) == -1 - || personality (0xffffffff) != PER_LINUX - || 0xdefaced != errno) - rc = 1; - - (void) personality (saved_persona); - return rc; + 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; } -#define TEST_FUNCTION do_test () -#include "../test-skeleton.c" +#include -- 2.43.5