[libvirt] [PATCH 2/2] Rework lxc apparmor profile
Serge Hallyn
serge.hallyn at ubuntu.com
Fri Jul 11 16:08:29 UTC 2014
Quoting Cédric Bosdonnat (cbosdonnat at suse.com):
> Rework the apparmor lxc profile abstraction to mimic ubuntu's container-default.
> This profile allows quite a lot, but strives to restrict access to
> dangerous resources.
>
> Removing the explicit authorizations to bash, systemd and cron files,
> forces them to keep the lxc profile for all applications inside the
> container. PUx permissions where leading to running systemd (and others
> tasks) unconfined.
>
> Put the generic files, network and capabilities restrictions directly
> in the TEMPLATE.lxc: this way, users can restrict them on a per
> container basis.
> ---
> examples/apparmor/Makefile.am | 6 +-
> examples/apparmor/TEMPLATE.lxc | 15 ++++
> examples/apparmor/{TEMPLATE => TEMPLATE.qemu} | 2 +-
> examples/apparmor/libvirt-lxc | 119 +++++++++++++++++++++++---
> src/security/security_apparmor.c | 20 +++--
> src/security/virt-aa-helper.c | 29 +------
> 6 files changed, 148 insertions(+), 43 deletions(-)
> create mode 100644 examples/apparmor/TEMPLATE.lxc
> rename examples/apparmor/{TEMPLATE => TEMPLATE.qemu} (75%)
>
> diff --git a/examples/apparmor/Makefile.am b/examples/apparmor/Makefile.am
> index a741e94..7a20e16 100644
> --- a/examples/apparmor/Makefile.am
> +++ b/examples/apparmor/Makefile.am
> @@ -15,7 +15,8 @@
> ## <http://www.gnu.org/licenses/>.
>
> EXTRA_DIST= \
> - TEMPLATE \
> + TEMPLATE.qemu \
> + TEMPLATE.lxc \
> libvirt-qemu \
> libvirt-lxc \
> usr.lib.libvirt.virt-aa-helper \
> @@ -36,6 +37,7 @@ abstractions_DATA = \
>
> templatesdir = $(apparmordir)/libvirt
> templates_DATA = \
> - TEMPLATE \
> + TEMPLATE.qemu \
> + TEMPLATE.lxc \
> $(NULL)
> endif WITH_APPARMOR_PROFILES
> diff --git a/examples/apparmor/TEMPLATE.lxc b/examples/apparmor/TEMPLATE.lxc
> new file mode 100644
> index 0000000..7b64885
> --- /dev/null
> +++ b/examples/apparmor/TEMPLATE.lxc
> @@ -0,0 +1,15 @@
> +#
> +# This profile is for the domain whose UUID matches this file.
> +#
> +
> +#include <tunables/global>
> +
> +profile LIBVIRT_TEMPLATE {
> + #include <abstractions/libvirt-lxc>
> +
> + # Globally allows everything to run under this profile
> + # These can be narrowed depending on the container's use.
> + file,
> + capability,
> + network,
> +}
> diff --git a/examples/apparmor/TEMPLATE b/examples/apparmor/TEMPLATE.qemu
> similarity index 75%
> rename from examples/apparmor/TEMPLATE
> rename to examples/apparmor/TEMPLATE.qemu
> index 187dec5..008a221 100644
> --- a/examples/apparmor/TEMPLATE
> +++ b/examples/apparmor/TEMPLATE.qemu
> @@ -5,5 +5,5 @@
> #include <tunables/global>
>
> profile LIBVIRT_TEMPLATE {
> - #include <abstractions/libvirt-driver>
> + #include <abstractions/libvirt-qemu>
> }
> diff --git a/examples/apparmor/libvirt-lxc b/examples/apparmor/libvirt-lxc
> index d404328..4bfb503 100644
> --- a/examples/apparmor/libvirt-lxc
> +++ b/examples/apparmor/libvirt-lxc
> @@ -2,16 +2,115 @@
>
> #include <abstractions/base>
>
> - # Needed for lxc-enter-namespace
> - capability sys_admin,
> - capability sys_chroot,
> + umount,
>
> - # Added for lxc-enter-namespace --cmd /bin/bash
> - /bin/bash PUx,
> + # ignore DENIED message on / remount
> + deny mount options=(ro, remount) -> /,
>
> - /usr/sbin/cron PUx,
> - /usr/lib/systemd/systemd PUx,
> + # allow tmpfs mounts everywhere
> + mount fstype=tmpfs,
>
> - /usr/lib/libsystemd-*.so.* mr,
> - /usr/lib/libudev-*.so.* mr,
> - /etc/ld.so.cache mr,
> + # allow mqueue mounts everywhere
> + mount fstype=mqueue,
> +
> + # allow fuse mounts everywhere
> + mount fstype=fuse.*,
> +
> + # deny writes in /proc/sys/fs but allow binfmt_misc to be mounted
> + mount fstype=binfmt_misc -> /proc/sys/fs/binfmt_misc/,
> + deny @{PROC}/sys/fs/** wklx,
> +
> + # allow efivars to be mounted, writing to it will be blocked though
> + mount fstype=efivarfs -> /sys/firmware/efi/efivars/,
> +
> + # block some other dangerous paths
> + deny @{PROC}/sysrq-trigger rwklx,
> + deny @{PROC}/mem rwklx,
> + deny @{PROC}/kmem rwklx,
> +
> + # deny writes in /sys except for /sys/fs/cgroup, also allow
> + # fusectl, securityfs and debugfs to be mounted there (read-only)
> + mount fstype=fusectl -> /sys/fs/fuse/connections/,
> + mount fstype=securityfs -> /sys/kernel/security/,
> + mount fstype=debugfs -> /sys/kernel/debug/,
> + mount fstype=proc -> /proc/,
> + mount fstype=sysfs -> /sys/,
> + deny /sys/firmware/efi/efivars/** rwklx,
> + deny /sys/kernel/security/** rwklx,
> +
> + # generated by: lxc-generate-aa-rules.py container-rules.base
> + deny /proc/sys/[^kn]*{,/**} wklx,
> + deny /proc/sys/k[^e]*{,/**} wklx,
> + deny /proc/sys/ke[^r]*{,/**} wklx,
> + deny /proc/sys/ker[^n]*{,/**} wklx,
> + deny /proc/sys/kern[^e]*{,/**} wklx,
> + deny /proc/sys/kerne[^l]*{,/**} wklx,
> + deny /proc/sys/kernel/[^smhd]*{,/**} wklx,
> + deny /proc/sys/kernel/d[^o]*{,/**} wklx,
> + deny /proc/sys/kernel/do[^m]*{,/**} wklx,
> + deny /proc/sys/kernel/dom[^a]*{,/**} wklx,
> + deny /proc/sys/kernel/doma[^i]*{,/**} wklx,
> + deny /proc/sys/kernel/domai[^n]*{,/**} wklx,
> + deny /proc/sys/kernel/domain[^n]*{,/**} wklx,
> + deny /proc/sys/kernel/domainn[^a]*{,/**} wklx,
> + deny /proc/sys/kernel/domainna[^m]*{,/**} wklx,
> + deny /proc/sys/kernel/domainnam[^e]*{,/**} wklx,
> + deny /proc/sys/kernel/domainname?*{,/**} wklx,
> + deny /proc/sys/kernel/h[^o]*{,/**} wklx,
> + deny /proc/sys/kernel/ho[^s]*{,/**} wklx,
> + deny /proc/sys/kernel/hos[^t]*{,/**} wklx,
> + deny /proc/sys/kernel/host[^n]*{,/**} wklx,
> + deny /proc/sys/kernel/hostn[^a]*{,/**} wklx,
> + deny /proc/sys/kernel/hostna[^m]*{,/**} wklx,
> + deny /proc/sys/kernel/hostnam[^e]*{,/**} wklx,
> + deny /proc/sys/kernel/hostname?*{,/**} wklx,
> + deny /proc/sys/kernel/m[^s]*{,/**} wklx,
> + deny /proc/sys/kernel/ms[^g]*{,/**} wklx,
> + deny /proc/sys/kernel/msg*/** wklx,
> + deny /proc/sys/kernel/s[^he]*{,/**} wklx,
> + deny /proc/sys/kernel/se[^m]*{,/**} wklx,
> + deny /proc/sys/kernel/sem*/** wklx,
> + deny /proc/sys/kernel/sh[^m]*{,/**} wklx,
> + deny /proc/sys/kernel/shm*/** wklx,
> + deny /proc/sys/kernel?*{,/**} wklx,
> + deny /proc/sys/n[^e]*{,/**} wklx,
> + deny /proc/sys/ne[^t]*{,/**} wklx,
> + deny /proc/sys/net?*{,/**} wklx,
> + deny /sys/[^fdc]*{,/**} wklx,
> + deny /sys/c[^l]*{,/**} wklx,
> + deny /sys/cl[^a]*{,/**} wklx,
> + deny /sys/cla[^s]*{,/**} wklx,
> + deny /sys/clas[^s]*{,/**} wklx,
> + deny /sys/class/[^n]*{,/**} wklx,
> + deny /sys/class/n[^e]*{,/**} wklx,
> + deny /sys/class/ne[^t]*{,/**} wklx,
> + deny /sys/class/net?*{,/**} wklx,
> + deny /sys/class?*{,/**} wklx,
> + deny /sys/d[^e]*{,/**} wklx,
> + deny /sys/de[^v]*{,/**} wklx,
> + deny /sys/dev[^i]*{,/**} wklx,
> + deny /sys/devi[^c]*{,/**} wklx,
> + deny /sys/devic[^e]*{,/**} wklx,
> + deny /sys/device[^s]*{,/**} wklx,
> + deny /sys/devices/[^v]*{,/**} wklx,
> + deny /sys/devices/v[^i]*{,/**} wklx,
> + deny /sys/devices/vi[^r]*{,/**} wklx,
> + deny /sys/devices/vir[^t]*{,/**} wklx,
> + deny /sys/devices/virt[^u]*{,/**} wklx,
> + deny /sys/devices/virtu[^a]*{,/**} wklx,
> + deny /sys/devices/virtua[^l]*{,/**} wklx,
> + deny /sys/devices/virtual/[^n]*{,/**} wklx,
> + deny /sys/devices/virtual/n[^e]*{,/**} wklx,
> + deny /sys/devices/virtual/ne[^t]*{,/**} wklx,
> + deny /sys/devices/virtual/net?*{,/**} wklx,
> + deny /sys/devices/virtual?*{,/**} wklx,
> + deny /sys/devices?*{,/**} wklx,
> + deny /sys/f[^s]*{,/**} wklx,
> + deny /sys/fs/[^c]*{,/**} wklx,
> + deny /sys/fs/c[^g]*{,/**} wklx,
> + deny /sys/fs/cg[^r]*{,/**} wklx,
> + deny /sys/fs/cgr[^o]*{,/**} wklx,
> + deny /sys/fs/cgro[^u]*{,/**} wklx,
> + deny /sys/fs/cgrou[^p]*{,/**} wklx,
> + deny /sys/fs/cgroup?*{,/**} wklx,
> + deny /sys/fs?*{,/**} wklx,
> diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c
> index 1e2a38b..778d233 100644
> --- a/src/security/security_apparmor.c
> +++ b/src/security/security_apparmor.c
> @@ -351,26 +351,36 @@ AppArmorSetSecuritySCSILabel(virSCSIDevicePtr dev ATTRIBUTE_UNUSED,
> static int
> AppArmorSecurityManagerProbe(const char *virtDriver ATTRIBUTE_UNUSED)
> {
> - char *template = NULL;
> + char *template_qemu = NULL;
> + char *template_lxc = NULL;
> int rc = SECURITY_DRIVER_DISABLE;
>
> if (use_apparmor() < 0)
> return rc;
>
> /* see if template file exists */
> - if (virAsprintf(&template, "%s/TEMPLATE",
> + if (virAsprintf(&template_qemu, "%s/TEMPLATE.qemu",
> APPARMOR_DIR "/libvirt") == -1)
> return rc;
>
> - if (!virFileExists(template)) {
> + if (virAsprintf(&template_lxc, "%s/TEMPLATE.lxc",
> + APPARMOR_DIR "/libvirt") == -1)
Hi,
something looks weird here. Is this (two lines above and 5 lines below)
intended, or are there missing lines?
> +
> + if (!virFileExists(template_qemu)) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("template \'%s\' does not exist"), template_qemu);
> + goto cleanup;
> + }
> + if (!virFileExists(template_lxc)) {
> virReportError(VIR_ERR_INTERNAL_ERROR,
> - _("template \'%s\' does not exist"), template);
> + _("template \'%s\' does not exist"), template_lxc);
> goto cleanup;
> }
> rc = SECURITY_DRIVER_ENABLE;
>
> cleanup:
> - VIR_FREE(template);
> + VIR_FREE(template_qemu);
> + VIR_FREE(template_lxc);
>
> return rc;
> }
> diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
> index d563b98..2a09145 100644
> --- a/src/security/virt-aa-helper.c
> +++ b/src/security/virt-aa-helper.c
> @@ -336,24 +336,20 @@ create_profile(const char *profile, const char *profile_name,
> char *pcontent = NULL;
> char *replace_name = NULL;
> char *replace_files = NULL;
> - char *replace_driver = NULL;
> const char *template_name = "\nprofile LIBVIRT_TEMPLATE";
> const char *template_end = "\n}";
> - const char *template_driver = "libvirt-driver";
> int tlen, plen;
> int fd;
> int rc = -1;
> - const char *driver_name = "qemu";
> -
> - if (virtType == VIR_DOMAIN_VIRT_LXC)
> - driver_name = "lxc";
>
> if (virFileExists(profile)) {
> vah_error(NULL, 0, _("profile exists"));
> goto end;
> }
>
> - if (virAsprintfQuiet(&template, "%s/TEMPLATE", APPARMOR_DIR "/libvirt") < 0) {
> +
> + if (virAsprintfQuiet(&template, "%s/TEMPLATE.%s", APPARMOR_DIR "/libvirt",
> + virDomainVirtTypeToString(virtType)) < 0) {
> vah_error(NULL, 0, _("template name exceeds maximum length"));
> goto end;
> }
> @@ -378,11 +374,6 @@ create_profile(const char *profile, const char *profile_name,
> goto clean_tcontent;
> }
>
> - if (strstr(tcontent, template_driver) == NULL) {
> - vah_error(NULL, 0, _("no replacement string in template"));
> - goto clean_tcontent;
> - }
> -
> /* '\nprofile <profile_name>\0' */
> if (virAsprintfQuiet(&replace_name, "\nprofile %s", profile_name) == -1) {
> vah_error(NULL, 0, _("could not allocate memory for profile name"));
> @@ -397,15 +388,7 @@ create_profile(const char *profile, const char *profile_name,
> goto clean_tcontent;
> }
>
> - /* 'libvirt-<driver_name>\0' */
> - if (virAsprintfQuiet(&replace_driver, "libvirt-%s", driver_name) == -1) {
> - vah_error(NULL, 0, _("could not allocate memory for profile driver"));
> - VIR_FREE(replace_driver);
> - goto clean_tcontent;
> - }
> -
> - plen = tlen + strlen(replace_name) - strlen(template_name) +
> - strlen(replace_driver) - strlen(template_driver) + 1;
> + plen = tlen + strlen(replace_name) - strlen(template_name) + 1;
>
> if (virtType != VIR_DOMAIN_VIRT_LXC)
> plen += strlen(replace_files) - strlen(template_end);
> @@ -422,9 +405,6 @@ create_profile(const char *profile, const char *profile_name,
> pcontent[0] = '\0';
> strcpy(pcontent, tcontent);
>
> - if (replace_string(pcontent, plen, template_driver, replace_driver) < 0)
> - goto clean_all;
> -
> if (replace_string(pcontent, plen, template_name, replace_name) < 0)
> goto clean_all;
>
> @@ -455,7 +435,6 @@ create_profile(const char *profile, const char *profile_name,
> clean_replace:
> VIR_FREE(replace_name);
> VIR_FREE(replace_files);
> - VIR_FREE(replace_driver);
> clean_tcontent:
> VIR_FREE(tcontent);
> end:
> --
> 1.8.4.5
>
> --
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