[libvirt] [PATCH v4 09/11] security: Label the external swtpm with SELinux labels

Marc Hartmayer mhartmay at linux.ibm.com
Tue May 15 15:38:39 UTC 2018


On Thu, May 10, 2018 at 11:57 PM +0200, Stefan Berger <stefanb at linux.vnet.ibm.com> wrote:
> In this patch we label the swtpm process with SELinux labels. We give it the
> same label as the QEMU process has. We label its state directory and files
> as well. We restore the old security labels once the swtpm has terminated.
>
> The file and process labels now look as follows:
>
> Directory: /var/lib/libvirt/swtpm
>
> [root at localhost swtpm]# ls -lZ
> total 4
> rwx------. 2 tss  tss  system_u:object_r:svirt_image_t:s0:c254,c932 4096 Apr  5 16:46 testvm
>
> [root at localhost testvm]# ls -lZ
> total 8
> -rw-r--r--. 1 tss tss system_u:object_r:svirt_image_t:s0:c254,c932 3648 Apr  5 16:46 tpm-00.permall
>
> The log in /var/log/swtpm/libvirt/qemu is labeled as follows:
>
> -rw-r--r--. 1 tss tss system_u:object_r:svirt_image_t:s0:c254,c932 2237 Apr  5 16:46 vtpm.log
>
> [root at localhost 485d0004-a48f-436a-8457-8a3b73e28567]# ps auxZ | grep swtpm | grep ctrl | grep -v grep
> system_u:system_r:svirt_t:s0:c254,c932 tss 25664 0.0  0.0 28172  3892 ?        Ss   16:57   0:00 /usr/bin/swtpm socket --daemon --ctrl type=unixio,path=/var/run/libvirt/qemu/swtpm/testvm-swtpm.sock,mode=0660 --tpmstate dir=/var/lib/libvirt/swtpm/testvm/tpm1.2 --log file=/var/log/swtpm/libvirt/qemu/testvm-swtpm.log
>
> [root at localhost 485d0004-a48f-436a-8457-8a3b73e28567]# ps auxZ | grep qemu | grep tpm | grep -v grep
> system_u:system_r:svirt_t:s0:c254,c932 qemu 25669 99.0  0.0 3096704 48500 ?    Sl   16:57   3:28 /bin/qemu-system-x86_64 [..]
>
> Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>
> ---
>  src/libvirt_private.syms        |   2 +
>  src/qemu/qemu_tpm.c             |  24 +++++-
>  src/security/security_driver.h  |   7 ++
>  src/security/security_manager.c |  36 +++++++++
>  src/security/security_manager.h |   6 ++
>  src/security/security_selinux.c | 164 ++++++++++++++++++++++++++++++++++++++++
>  src/security/security_stack.c   |  40 ++++++++++
>  7 files changed, 278 insertions(+), 1 deletion(-)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 75b8932..2ce67e7 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1319,6 +1319,7 @@ virSecurityManagerRestoreImageLabel;
>  virSecurityManagerRestoreInputLabel;
>  virSecurityManagerRestoreMemoryLabel;
>  virSecurityManagerRestoreSavedStateLabel;
> +virSecurityManagerRestoreTPMLabels;
>  virSecurityManagerSetAllLabel;
>  virSecurityManagerSetChardevLabel;
>  virSecurityManagerSetChildProcessLabel;
> @@ -1333,6 +1334,7 @@ virSecurityManagerSetProcessLabel;
>  virSecurityManagerSetSavedStateLabel;
>  virSecurityManagerSetSocketLabel;
>  virSecurityManagerSetTapFDLabel;
> +virSecurityManagerSetTPMLabels;
>  virSecurityManagerStackAddNested;
>  virSecurityManagerTransactionAbort;
>  virSecurityManagerTransactionCommit;
> diff --git a/src/qemu/qemu_tpm.c b/src/qemu/qemu_tpm.c
> index 024d24d..62f0146 100644
> --- a/src/qemu/qemu_tpm.c
> +++ b/src/qemu/qemu_tpm.c
> @@ -684,7 +684,26 @@ qemuExtTPMStartEmulator(virQEMUDriverPtr driver,
>
>      virCommandSetErrorBuffer(cmd, &errbuf);
>
> -    if (virCommandRun(cmd, &exitstatus) < 0 || exitstatus != 0) {
> +    if (virSecurityManagerSetTPMLabels(driver->securityManager,
> +                                       def) < 0)
> +        goto cleanup;
> +
> +    if (virSecurityManagerSetChildProcessLabel(driver->securityManager,
> +                                               def, cmd) < 0)
> +        goto cleanup;
> +
> +    if (virSecurityManagerPreFork(driver->securityManager) < 0)
> +        goto cleanup;
> +
> +    /* make sure we run this with the appropriate user */
> +    virCommandSetUID(cmd, cfg->swtpm_user);
> +    virCommandSetGID(cmd, cfg->swtpm_group);
> +
> +    ret = virCommandRun(cmd, &exitstatus);
> +
> +    virSecurityManagerPostFork(driver->securityManager);
> +
> +    if (ret < 0 || exitstatus != 0) {
>          VIR_ERROR(_("Could not start 'swtpm'. exitstatus: %d "
>                      "stderr: %s"), exitstatus, errbuf);
>          virReportError(VIR_ERR_INTERNAL_ERROR,

Don't we have to set ret to -1 here (for the case where ret == 0 &&
exitstatus != 0)?

[…snip]

Beste Grüße / Kind regards
   Marc Hartmayer

IBM Deutschland Research & Development GmbH
Vorsitzende des Aufsichtsrats: Martina Koederitz
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294





More information about the libvir-list mailing list