This is a forward-port of commit 91fa032da4 ("ci: add basic checks for
CHANGELOG.md"), plus whatever changes were made in release-1.1 branch
(up to v1.1.3).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
On s390x, syscalls above 255 are multiplexed using the (now otherwise
unused) setup(2) syscall (syscall number 0). If the kernel supports the
syscall then it will correctly translate the syscall number such that
seccomp will correctly detect it -- however, for unknown syscalls the
syscall number remains unchanged. This can be verified by running the
following program under strace:
int main(void)
{
scmp_filter_ctx ctx = seccomp_init(SCMP_ACT_TRAP);
seccomp_load(ctx);
return syscall(439, AT_FDCWD, "asdf", X_OK, 0);
}
Which will then die with the following signal (on pre-5.8 kernels):
--- SIGSYS {si_signo=SIGSYS, si_code=SYS_SECCOMP,
si_call_addr=0x3ffb3006c22, si_syscall=__NR_setup,
si_arch=AUDIT_ARCH_S390X} ---
(Note that the si_syscall is __NR_setup, not __NR_faccessat2.)
As a result, the -ENOSYS handling we had previously did not work
completely correctly on s390x because any syscall not supported by the
kernel would be treated as syscall number 0 rather than the actual
syscall number.
Always returning -ENOSYS will not cause any issues because in all of the
cases where this multiplexing occurs, seccomp will see the remapped
syscall number -- and no userspace program will call setup(2)
intentionally (the syscall has not existed in Linux for decades and was
originally a hack used early in Linux init prior to spawning pid1 -- so
you will get -ENOSYS from the kernel anyway).
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
After adding some debug info to cloned_binary.c I found out that
is_self_cloned() is not working right when runc binary is on tmpfs,
resulting in one extra re-exec of runc.
With some added debug:
$ mkdir bin
$ sudo mount -t tmpfs tmp bin
$ sudo cp runc bin
$ sudo ./bin/runc --debug exec xxx true
DEBU[0000] nsexec[763590]: => is_self_cloned
DEBU[0000] nsexec[763590]: got seals 1 (want 15)
DEBU[0000] nsexec[763590]: <= is_self_cloned, is_cloned = 0
DEBU[0000] nsexec[763590]: try_bindfd: 5
DEBU[0000] nsexec[763590]: re-exec itself...
DEBU[0000] nsexec[763590]: => is_self_cloned
DEBU[0000] nsexec[763590]: got seals 1 (want 15)
DEBU[0000] nsexec[763590]: <= is_self_cloned, is_cloned = 0
DEBU[0000] nsexec[763590]: try_bindfd: -1
DEBU[0000] nsexec[763590]: fallback to make_execfd: 5
DEBU[0000] nsexec[763590]: re-exec itself...
DEBU[0000] nsexec[763590]: => is_self_cloned
DEBU[0000] nsexec[763590]: got seals 15 (want 15)
DEBU[0000] nsexec[763590]: <= is_self_cloned, is_cloned = 1
From the above, it is seen that
- `is_self_cloned` returns 0,
- `try_bindfd` is called and succeeds,
- runc re-execs itself,
- the second call to `is_self_cloned` returns 0 again (because GET_SEALS returns 1),
- runc falls back to `make_execfd`, and re-execs again,
- finally, the third `is_self_cloned` returns 1.
I guess that the code relied on the following (quoting fcntl(2)):
> Currently, file seals can be applied only to a file descriptor
> returned by memfd_create(2) (if the MFD_ALLOW_SEALING was employed).
> On other filesystems, all fcntl() operations that operate on seals
> will return EINVAL.
It looks like in case of a file on tmpfs it returns 1 (F_SEAL_SEAL).
With the fix:
DEBU[0000] nsexec[768367]: => is_self_cloned
DEBU[0000] nsexec[768367]: got seals 1 (want 15)
DEBU[0000] nsexec[768367]: no CLONED_BINARY_ENV
DEBU[0000] nsexec[768367]: <= is_self_cloned, is_cloned = 0
DEBU[0000] nsexec[768367]: try_bindfd: 5
DEBU[0000] nsexec[768367]: re-exec itself...
DEBU[0000] nsexec[768367]: => is_self_cloned
DEBU[0000] nsexec[768367]: got seals 1 (want 15)
DEBU[0000] nsexec[768367]: fstatfs says ro = 1
DEBU[0000] nsexec[768367]: fstat says nlink = 1
DEBU[0000] nsexec[768367]: <= is_self_cloned, is_cloned = 1
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This was introduced in an initial commit, back in the day when criu was
a highly experimental thing. Today it's not; most users who need it have
it packaged by their distro vendor.
The usual way to run a binary is to look it up in directories listed in
$PATH. This is flexible enough and allows for multiple scenarios (custom
binaries, extra binaries, etc.). This is the way criu should be run.
Make --criu a hidden option (thus removing it from help). Remove the
option from man pages, integration tests, etc. Remove all traces of
CriuPath from data structures.
Add a warning that --criu is ignored and will be removed.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This will make releases much simpler. I've back-filled the changelog
with everything since runc 1.0.0 (there's not much point going further
back than that).
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Kir Kolyshkin