The seclabel for @stdin_path in virSecuritySELinuxSetAllLabel() is not restored, because at virSecuritySELinuxRestoreAllLabel() phase it's too late and the caller (QEMU driver) simply doesn't care. Well, don't remember the label and let the perms leak. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/security/security_selinux.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c index 8aeb6e45a5..f47bfbdba9 100644 --- a/src/security/security_selinux.c +++ b/src/security/security_selinux.c @@ -3233,7 +3233,7 @@ virSecuritySELinuxSetAllLabel(virSecurityManagerPtr mgr, if (stdin_path && virSecuritySELinuxSetFilecon(mgr, stdin_path, - data->content_context, true) < 0) + data->content_context, false) < 0) return -1; return 0; -- 2.24.1

This API allows drivers to separate out handling of @stdin_path of virSecurityManagerSetAllLabel(). The thing is, the QEMU driver uses transactions for virSecurityManagerSetAllLabel() which relabels devices from inside of domain's namespace. This is what we usually want. Except when resuming domain from a file. The file is opened before any namespace is set up and the FD is passed to QEMU to read the migration stream from. Because of this, the file lives outside of the namespace and if it so happens that the file is a block device (i.e. it lives under /dev) its copy will be created in the namespace. But the FD that is passed to QEMU points to the original living in the host and not in the namespace. So relabeling the file inside the namespace helps nothing. But if we have a separate API for relabeling the restore file then the QEMU driver can continue calling virSecurityManagerSetAllLabel() with transactions enabled and call this new API without transactions. We already have an API for relabeling a single file (virSecurityManagerDomainSetPathLabel()) but in case of SELinux it uses @imagelabel (which allows RW access) and we want to use @content_context (which allows RO access). Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/libvirt_private.syms | 1 + src/security/security_driver.h | 4 ++++ src/security/security_manager.c | 29 +++++++++++++++++++++++++++++ src/security/security_manager.h | 4 ++++ src/security/security_stack.c | 21 +++++++++++++++++++++ 5 files changed, 59 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index e276f55bb1..2c63f37fc2 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1523,6 +1523,7 @@ virSecurityDriverLookup; # security/security_manager.h virSecurityManagerCheckAllLabel; virSecurityManagerClearSocketLabel; +virSecurityManagerDomainSetIncomingPathLabel; virSecurityManagerDomainSetPathLabel; virSecurityManagerGenLabel; virSecurityManagerGetBaseLabel; diff --git a/src/security/security_driver.h b/src/security/security_driver.h index 3353955813..6cbe8613c9 100644 --- a/src/security/security_driver.h +++ b/src/security/security_driver.h @@ -140,6 +140,9 @@ typedef int (*virSecurityDomainSetPathLabel) (virSecurityManagerPtr mgr, virDomainDefPtr def, const char *path, bool allowSubtree); +typedef int (*virSecurityDomainSetIncomingPathLabel) (virSecurityManagerPtr mgr, + virDomainDefPtr def, + const char *path); typedef int (*virSecurityDomainSetChardevLabel) (virSecurityManagerPtr mgr, virDomainDefPtr def, virDomainChrSourceDefPtr dev_source, @@ -211,6 +214,7 @@ struct _virSecurityDriver { virSecurityDriverGetBaseLabel getBaseLabel; virSecurityDomainSetPathLabel domainSetPathLabel; + virSecurityDomainSetIncomingPathLabel domainSetIncomingPathLabel; virSecurityDomainSetChardevLabel domainSetSecurityChardevLabel; virSecurityDomainRestoreChardevLabel domainRestoreSecurityChardevLabel; diff --git a/src/security/security_manager.c b/src/security/security_manager.c index fe032746ff..a76b953ee4 100644 --- a/src/security/security_manager.c +++ b/src/security/security_manager.c @@ -1077,6 +1077,35 @@ virSecurityManagerDomainSetPathLabel(virSecurityManagerPtr mgr, } +/** + * virSecurityManagerDomainSetIncomingPathLabel: + * @mgr: security manager object + * @vm: domain definition object + * @path: path to label + * + * This function relabels given @path so that @vm can restore for + * it. This allows the driver backend to use different label than + * virSecurityManagerDomainSetPathLabel(). + * + * Returns: 0 on success, -1 on error. + */ +int +virSecurityManagerDomainSetIncomingPathLabel(virSecurityManagerPtr mgr, + virDomainDefPtr vm, + const char *path) +{ + if (mgr->drv->domainSetIncomingPathLabel) { + int ret; + virObjectLock(mgr); + ret = mgr->drv->domainSetIncomingPathLabel(mgr, vm, path); + virObjectUnlock(mgr); + return ret; + } + + return 0; +} + + /** * virSecurityManagerSetMemoryLabel: * @mgr: security manager object diff --git a/src/security/security_manager.h b/src/security/security_manager.h index 7699bcbc6f..465d71558f 100644 --- a/src/security/security_manager.h +++ b/src/security/security_manager.h @@ -189,6 +189,10 @@ int virSecurityManagerDomainSetPathLabel(virSecurityManagerPtr mgr, const char *path, bool allowSubtree); +int virSecurityManagerDomainSetIncomingPathLabel(virSecurityManagerPtr mgr, + virDomainDefPtr vm, + const char *path); + int virSecurityManagerSetChardevLabel(virSecurityManagerPtr mgr, virDomainDefPtr def, virDomainChrSourceDefPtr dev_source, diff --git a/src/security/security_stack.c b/src/security/security_stack.c index 073876daff..7782abaf9d 100644 --- a/src/security/security_stack.c +++ b/src/security/security_stack.c @@ -825,6 +825,26 @@ virSecurityStackDomainSetPathLabel(virSecurityManagerPtr mgr, return rc; } + +static int +virSecurityStackDomainSetIncomingPathLabel(virSecurityManagerPtr mgr, + virDomainDefPtr vm, + const char *path) +{ + virSecurityStackDataPtr priv = virSecurityManagerGetPrivateData(mgr); + virSecurityStackItemPtr item = priv->itemsHead; + int rc = 0; + + for (; item; item = item->next) { + if (virSecurityManagerDomainSetIncomingPathLabel(item->securityManager, + vm, path) < 0) + rc = -1; + } + + return rc; +} + + static int virSecurityStackDomainSetChardevLabel(virSecurityManagerPtr mgr, virDomainDefPtr def, @@ -985,6 +1005,7 @@ virSecurityDriver virSecurityDriverStack = { .getBaseLabel = virSecurityStackGetBaseLabel, .domainSetPathLabel = virSecurityStackDomainSetPathLabel, + .domainSetIncomingPathLabel = virSecurityStackDomainSetIncomingPathLabel, .domainSetSecurityChardevLabel = virSecurityStackDomainSetChardevLabel, .domainRestoreSecurityChardevLabel = virSecurityStackDomainRestoreChardevLabel, -- 2.24.1

As explained in the previous commit, we need to relabel the file we are restoring the domain from. That is the FD that is passed to QEMU. If the file is not under /dev then the file inside the namespace is the very same as the one in the host. And regardless of using transactions, the file will be relabeled. But, if the file is under /dev then when using transactions only the copy inside the namespace is relabeled and the one in the host is not. But QEMU is reading from the one in the host, actually. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1772838 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu_security.c | 7 +++++++ src/security/security_selinux.c | 23 +++++++++++++++++------ 2 files changed, 24 insertions(+), 6 deletions(-) diff --git a/src/qemu/qemu_security.c b/src/qemu/qemu_security.c index 484fc34552..594a700ea3 100644 --- a/src/qemu/qemu_security.c +++ b/src/qemu/qemu_security.c @@ -39,6 +39,13 @@ qemuSecuritySetAllLabel(virQEMUDriverPtr driver, qemuDomainObjPrivatePtr priv = vm->privateData; pid_t pid = -1; + /* Explicitly run this outside of transaction. We really want to relabel + * the file in the host and not in the domain's namespace. */ + if (virSecurityManagerDomainSetIncomingPathLabel(driver->securityManager, + vm->def, + stdin_path) < 0) + goto cleanup; + if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT)) pid = vm->pid; diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c index f47bfbdba9..4d8f755c10 100644 --- a/src/security/security_selinux.c +++ b/src/security/security_selinux.c @@ -3135,7 +3135,7 @@ virSecuritySELinuxSetSecuritySmartcardCallback(virDomainDefPtr def, static int virSecuritySELinuxSetAllLabel(virSecurityManagerPtr mgr, virDomainDefPtr def, - const char *stdin_path, + const char *stdin_path G_GNUC_UNUSED, bool chardevStdioLogd, bool migrated G_GNUC_UNUSED) { @@ -3231,11 +3231,6 @@ virSecuritySELinuxSetAllLabel(virSecurityManagerPtr mgr, data->content_context, true) < 0) return -1; - if (stdin_path && - virSecuritySELinuxSetFilecon(mgr, stdin_path, - data->content_context, false) < 0) - return -1; - return 0; } @@ -3393,6 +3388,21 @@ virSecuritySELinuxDomainSetPathLabel(virSecurityManagerPtr mgr, return virSecuritySELinuxSetFilecon(mgr, path, seclabel->imagelabel, true); } +static int +virSecuritySELinuxDomainSetIncomingPathLabel(virSecurityManagerPtr mgr, + virDomainDefPtr def, + const char *path) +{ + virSecuritySELinuxDataPtr data = virSecurityManagerGetPrivateData(mgr); + virSecurityLabelDefPtr secdef; + + secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME); + + if (!path || !secdef || !secdef->relabel || data->skipAllLabel) + return 0; + + return virSecuritySELinuxSetFilecon(mgr, path, data->content_context, false); +} /* * virSecuritySELinuxSetFileLabels: @@ -3596,6 +3606,7 @@ virSecurityDriver virSecurityDriverSELinux = { .getBaseLabel = virSecuritySELinuxGetBaseLabel, .domainSetPathLabel = virSecuritySELinuxDomainSetPathLabel, + .domainSetIncomingPathLabel = virSecuritySELinuxDomainSetIncomingPathLabel, .domainSetSecurityChardevLabel = virSecuritySELinuxSetChardevLabel, .domainRestoreSecurityChardevLabel = virSecuritySELinuxRestoreChardevLabel, -- 2.24.1