Fairly severe, but can be disabled at bootup via
grsec_sysfs_restrict=0. For the NixOS module we ensure that it is
disabled, for systemd compatibility.
Previously, we would only set a default value, on the theory that
`boot.kernelPackages` could be used to sanely configure a custom grsec
kernel. Regrettably, this is not the case and users who expect e.g.,
`boot.kernelPackages = pkgs.linuxPackages_latest` to work will end up
with a non-grsec kernel (this problem has come up twice on the bug
tracker recently).
With this patch, `security.grsecurity.enable = true` implies
`boot.kernelPackages = linuxPackages_grsec_nixos` and any customization
must be done via package override or by eschewing the module.
Using a custom package set with the NixOS module is no longer
something I wish to support. It's still *possible* but not
advertised. Secondly, the requiredKernelConfig didn't really
do anything (setting kernelPackages to a non-grsec kernel would
just silently let the user boot into a non-grsec setup ...).
Previously, the list of CA certificates was generated with a perl script
which is included in curl. As this script is not very flexible, this commit
refactors the expression to use the python script that Debian uses to
generate their CA certificates from Mozilla's trust store in NSS.
Additionally, an option was added to the cacerts derivation and the
`security.pki` module to blacklist specific CAs.
It looks like the cpu type part of modalias might have changed, my
systems (4.4.20 and 4.7.2) show something like the following:
```
cpu:type:x86,ven0000fam0006mod003F:feature:,0000,0001,0002,0003,0004,0005,0006,0007,0008,0009,000B,000C,000D,000E,000F,0010,0011,0013,0017,0018,0019,001A,001C,002B,0034,003B,003D,0068,006F,0070,0072,0074,0075,0076,007D,0080,0081,0089,008C,008D,0091,0093,0094,0095,0096,0097,0098,0099,009A,009B,009C,009D,009E,009F,00C0,00C5,0120,0123,0125,0127,0128,0129,012A,0140
```
Update the rngd modalias rule to match this so udev properly has
systemd start rngd.
This reverts commit 1010271c63.
This reverts commit e85e51d41f.
The first commit causes multiple regressions. The second commit tries to
fix the regressions, but does not catch all of them. There are multiple
failing tests, one of which is blocking a package update. That is not
acceptable for a cosmetic patch.
Regression introduced by 1010271c63.
This caused the line after using the loginuid module to be concatenated
with the next line without a newline.
In turn this has caused a lot of the NixOS VM tests to either run very
slowly (because of constantly hitting PAM errors) or simply fail.
I have tested this only with one of the failing NixOS tests.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
The generated files in /etc/pam.d/ typically have a lot of empty lines
in them, due to how the generated Nix strings are joined together;
optional elements that are excluded still produce a newline. This patch
changes how the files are generated to create more compact,
human-friendly output files.
The change is basically this, repeated:
- ''
- ${optionalString use_ldap
- "account sufficient ${pam_ldap}/lib/security/pam_ldap.so"}
- ''
+ optionalString use_ldap ''
+ account sufficient ${pam_ldap}/lib/security/pam_ldap.so
+ ''
Before this commit updating /var/setuid-wrappers/ folder introduced
a small window where NixOS activation scripts could be terminated
and resulted into empty /var/setuid-wrappers/ folder.
That's very unfortunate because one might lose sudo binary.
Instead we use two atomic operations mv and ln (as described in
https://axialcorps.com/2013/07/03/atomically-replacing-files-and-directories/)
to achieve atomicity.
Since /var/setuid-wrappers is not a directory anymore, tmpfs mountpoints
were removed in installation scripts and in boot process.
Tested:
- upgrade /var/setuid-wrappers/ from folder to a symlink
- make sure /run/setuid-wrappers-dirs/ legacy symlink is really deleted
A new internal config option `fileSystems.<name>.early` is added to indicate
that the filesystem needs to be loaded very early (i.e. in initrd). They are
transformed to a shell script in `system.build.earlyMountScript` with calls to
an undefined `specialMount` function, which is expected to be caller-specific.
This option is used by stage-1, stage-2 and activation script to set up and
remount those filesystems. Options for them are updated according to systemd
defaults.
While useless, some builds may dabble with setuid bits (e.g.,
util-linux), which breaks under grsec. In the interest of user
friendliness, we once again compromise by disabling an otherwise useful
feature ...
Closes https://github.com/NixOS/nixpkgs/issues/17501
Closes#17460
Changed the wrapper derivation to produce a second output containing the sandbox.
Add a launch wrapper to try and locate the sandbox (either in /var/setuid-wrappers or in /nix/store).
This launch wrapper also sheds libredirect.so from LD_PRELOAD as Chromium does not tolerate it.
Does not trigger a Chromium rebuild.
cc @cleverca22 @joachifm @jasom
Enabling EFI runtime services provides a venue for injecting code into
the kernel.
When grsecurity is enabled, we close this by default by disabling access
to EFI runtime services. The upshot of this is that
/sys/firmware/efi/efivars will be unavailable by default (and attempts
to mount it will fail).
This is not strictly a grsecurity related option, it could be made into
a general option, but it seems to be of particular interest to
grsecurity users (for non-grsecurity users, there are other, more
immediate kernel injection attack dangers to contend with anyway).
The new module is specifically adapted to the NixOS Grsecurity/PaX
kernel. The module declares the required kernel configurations and
so *should* be somewhat compatible with custom Grsecurity kernels.
The module exposes only a limited number of options, minimising the need
for user intervention beyond enabling the module. For experts,
Grsecurity/PaX behavior may be configured via `boot.kernelParams` and
`boot.kernel.sysctl`.
The module assumes the user knows what she's doing (esp. if she decides
to modify configuration values not directly exposed by the module).
Administration of Grsecurity's role based access control system is yet
to be implemented.
The motivation is using sudo in chroot nix builds, a somewhat
special edge case I have and pulling system path into chroot
yields to some very nasty bug like
https://github.com/NixOS/nixpkgs/issues/15581
Previously:
$ cat /var/setuid-wrappers/sudo.real
/nix/store/3sm04dzh0994r86xqxy52jjc0lqnkn65-system-path/bin/sudo
After the change:
$ cat /var/setuid-wrappers/sudo.real
/nix/store/4g9sxbzy8maxf1v217ikp69c0c3q12as-sudo-1.8.15/bin/sudo
The chroot caps restriction disallows chroot'ed processes from running
any command that requires `CAP_SYS_ADMIN`, breaking `nixos-rebuild`. See
e.g., https://github.com/NixOS/nixpkgs/issues/15293
This significantly weakens chroot protections, but to break
nixos-rebuild out of the box is too severe.
This module adds an option `security.hideProcessInformation` that, when
enabled, restricts access to process information such as command-line
arguments to the process owner. The module adds a static group "proc"
whose members are exempt from process information hiding.
Ideally, this feature would be implemented by simply adding the
appropriate mount options to `fileSystems."/proc".fsOptions`, but this
was found to not work in vmtests. To ensure that process information
hiding is enforced, we use a systemd service unit that remounts `/proc`
after `systemd-remount-fs.service` has completed.
To verify the correctness of the feature, simple tests were added to
nixos/tests/misc: the test ensures that unprivileged users cannot see
process information owned by another user, while members of "proc" CAN.
Thanks to @abbradar for feedback and suggestions.
Add a module to make options to pam_oath module configurable.
These are:
- enable - enable the OATH pam module
- window - number of OTPs to check
- digits - length of the OTP (adds support for two-factor auth)
- usersFile - filename to store OATH credentials in
- Now `pkg.outputUnspecified = true` but this attribute is missing in
every output, so we can recognize whether the user chose or not.
If (s)he didn't choose, we put `pkg.bin or pkg.out or pkg` into
`systemPackages`.
- `outputsToLink` is replaced by `extraOutputsToLink`.
We add extra outputs *regardless* of whether the user chose anything.
It's mainly meant for outputs with docs and debug symbols.
- Note that as a result, some libraries will disappear from system path.
Part of the way towards #11864. We still don't have the auditd
userland logging daemon, but journald also tracks audit logs so we
can already use this.
Run pam_unix an additional time rather than switching it from sufficient
to required. This fixes a potential security issue for
ecryptfs/pam_mount users as with pam_deny gone, if cfg.unixAuth = False
then it is possible to login without a password.
- upgrade 106 -> 108
- fix passphrase rewrapper (password changing should now work fine) as
discussed on https://bugs.launchpad.net/ecryptfs/+bug/1486470
- add lsof dependency so ecryptfs-migrate-home should work out of the
box
Enables attaching AppArmor profiles at the user/group level.
This is not intended to be used directly, but as part of a
role-based access control scheme. For now, profile attachment
is 'session optional', but should be changed to 'required' once
a more comprehensive solution is in place.
This allows for module arguments to be handled modularly, in particular
allowing the nixpkgs module to handle the nixpkgs import internally.
This creates the __internal option namespace, which should only be added
to by the module system itself.
The grsec-lock unit fails unless /proc/sys/kernel/grsecurity/grsec_lock
exists and so prevents switching into a new configuration after enabling
grsecurity.sysctl.
There is no "standard" location for the certificate bundle, so many
programs/libraries have various hard-coded default locations that
don't exist on NixOS. To make these more likely to work, provide
some symlinks.
The option had been added to the grsec build-support code,
but it hadn't been added to the grsec module.
After this commit, grsec module users will be able to change
the default value. It also serves to document that this option
exists and that NixOS will disable it by default.
from sudoers (5):
When multiple entries match for a user, they are applied in order.
Where there are multiple matches, the last match is used (which is not necessarily the most specific match).
It's more standard than $OPENSSL_X509_CERT_FILE (which I guess was a
totally unnecessary patch to OpenSSL). Since curl respects
$SSL_CERT_FILE, it's no longer needed to set $CURL_CA_BUNDLE. Git
unfortunately doesn't.
This updates the new stable kernel to 3.14, and the new testing kernel
to 3.15.
This also removes the vserver kernel, since it's probably not nearly as
used.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
This now provides a handful of different grsecurity kernels for slightly
different 'flavors' of packages. This doesn't change the grsecurity
module to use them just yet, however.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
AppArmor only requires a few patches to the 3.2 and 3.4 kernels in order
to work properly (with the minor catch grsecurity -stable includes the
3.2 patches.) This adds them to the kernel builds by default, removes
features.apparmor (since it's always true) and makes it the default MAC
system.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Only one process can interact with the TPM module and
that process should be tcsd. The tpm_rng kernel module
should instead be loaded and /dev/hwrnd be used to
read the TPM random generator.
Also, log which random generator devices are used by
rngd on startup.
This mostly upgrades transmission, and does some very minor touchups on
AppArmor support.
In particular, there is now no need to ever specify the umask as part of
the settings, as it will be mixed in by default (which is essentially
always what you want). Also, the default configuration is now more
sensible: Downloads are put in /var/lib/transmission/Downloads, and
incomplete files are put in /var/lib/transmission/.incomplete - this
also allows easy use of file syncing probrams, like BitTorrent Sync.
Finally, this unconditionally enables the AppArmor profiles for the
daemon, if AppArmor is enabled - rather than letting the user specify
profile support, it's best to default to supporting profiles for daemons
transparently in all places.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
Previously we were setting GRKERNSEC_PROC_USER y, which was a little bit
too strict. It doesn't allow a special group (e.g. the grsecurity group
users) to access /proc information - this requires
GRKERNSEC_PROC_USERGROUP y, and the two are mutually exclusive.
This was also not in line with the default automatic grsecurity
configuration - it actually defaults to USERGROUP (although it has a
default GID of 1001 instead of ours), not USER.
This introduces a new option restrictProcWithGroup - enabled by default
- which turns on GRKERNSEC_PROC_USERGROUP instead. It also turns off
restrictProc by default and makes sure both cannot be enabled.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
This module implements a significant refactoring in grsecurity
configuration for NixOS, making it far more usable by default and much
easier to configure.
- New security.grsecurity NixOS attributes.
- All grsec kernels supported
- Allows default 'auto' grsec configuration, or custom config
- Supports custom kernel options through kernelExtraConfig
- Defaults to high-security - user must choose kernel, server/desktop
mode, and any virtualisation software. That's all.
- kptr_restrict is fixed under grsecurity (it's unwriteable)
- grsecurity patch creation is now significantly abstracted
- only need revision, version, and SHA1
- kernel version requirements are asserted for sanity
- built kernels can have the uname specify the exact grsec version
for development or bug reports. Off by default (requires
`security.grsecurity.config.verboseVersion = true;`)
- grsecurity sysctl support
- By default, disabled.
- For people who enable it, NixOS deploys a 'grsec-lock' systemd
service which runs at startup. You are expected to configure sysctl
through NixOS like you regularly would, which will occur before the
service is started. As a result, changing sysctl settings requires
a reboot.
- New default group: 'grsecurity'
- Root is a member by default
- GRKERNSEC_PROC_GID is implicitly set to the 'grsecurity' GID,
making it possible to easily add users to this group for /proc
access
- AppArmor is now automatically enabled where it wasn't before, despite
implying features.apparmor = true
The most trivial example of enabling grsecurity in your kernel is by
specifying:
security.grsecurity.enable = true;
security.grsecurity.testing = true; # testing 3.13 kernel
security.grsecurity.config.system = "desktop"; # or "server"
This specifies absolutely no virtualisation support. In general, you
probably at least want KVM host support, which is a little more work.
So:
security.grsecurity.enable = true;
security.grsecurity.stable = true; # enable stable 3.2 kernel
security.grsecurity.config = {
system = "server";
priority = "security";
virtualisationConfig = "host";
virtualisationSoftware = "kvm";
hardwareVirtualisation = true;
}
This module has primarily been tested on Hetzner EX40 & VQ7 servers
using NixOps.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
This module adds the security.duosec attributes, which you can use to
enable simple two-factor authentication for NixOS logins.
The module currently provides PAM and SSH support, although the PAM unix
system configuration isn't automatically dealt with (although the
configuration is automatically built).
Enabling it is as easy as saying:
security.duosec.ssh.enable = true;
security.duosec.ikey = "XXXXXXXX...";
security.duosec.skey = "XXXXXXXX...";
security.duosec.host = "api-XXXXXXX.duosecurity.com";
security.duosec.group = "duosec";
which will enforce two-factor authentication for SSH logins for users in
the 'duosec' group.
This requires uid/gid support in the environment.etc module.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
- It now uses JavaScript for configuration (only),
so I had to "convert" config for NetworkManager.
- I tested suspend/restart/(un)mount on KDE/Xfce,
Phreedom tested NetworkManager config conversion.
Sshd *must* use PAM because we depend on it for proper session
management. The original goal of this option (disabling password
logins) can also be implemented by removing pam_auth authentication
from sshd's PAM service.
That is, you can say
security.pam.services.sshd = { options... };
instead of
security.pam.services = [ { name = "sshd"; options... } ];
making it easier to override PAM settings from other modules.
