[libvirt] [PATCH v2 2/2] selinux: add security selinux function to label tapfd
Guannan Ren
gren at redhat.com
Mon Oct 15 09:03:49 UTC 2012
BZ:https://bugzilla.redhat.com/show_bug.cgi?id=851981
When using macvtap, a character device gets first created by
kernel with name /dev/tapN, its selinux context is:
system_u:object_r:device_t:s0
Shortly, when udev gets notification when new file is created
in /dev, it will then jump in and relabel this file back to the
expected default context:
system_u:object_r:tun_tap_device_t:s0
There is a time gap happened.
Sometimes, it will have migration failed, AVC error message:
type=AVC msg=audit(1349858424.233:42507): avc: denied { read write } for
pid=19926 comm="qemu-kvm" path="/dev/tap33" dev=devtmpfs ino=131524
scontext=unconfined_u:system_r:svirt_t:s0:c598,c908
tcontext=system_u:object_r:device_t:s0 tclass=chr_file
This patch will label the tapfd device before qemu process starts:
system_u:object_r:tun_tap_device_t:MCS(MCS from seclabel->label)
---
src/libvirt_private.syms | 1 +
src/qemu/qemu_command.c | 4 ++
src/security/security_apparmor.c | 10 ++++
src/security/security_dac.c | 9 +++
src/security/security_driver.h | 4 ++
src/security/security_manager.c | 11 ++++
src/security/security_manager.h | 3 +
src/security/security_nop.c | 3 +-
src/security/security_selinux.c | 118 +++++++++++++++++++++++++++++++--------
src/security/security_stack.c | 18 ++++++
10 files changed, 156 insertions(+), 25 deletions(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 6ea1308..1703f6d 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1056,6 +1056,7 @@ virSecurityManagerSetHostdevLabel;
virSecurityManagerSetProcessLabel;
virSecurityManagerSetSavedStateLabel;
virSecurityManagerSetSocketLabel;
+virSecurityManagerSetTapFDLabel;
virSecurityManagerStackAddNested;
virSecurityManagerVerify;
virSecurityManagerGetMountOptions;
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index d590df6..239592c 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -5412,6 +5412,10 @@ qemuBuildCommandLine(virConnectPtr conn,
if (tapfd < 0)
goto error;
+ if (virSecurityManagerSetTapFDLabel(driver->securityManager,
+ def, tapfd) < 0)
+ goto error;
+
last_good_net = i;
virCommandTransferFD(cmd, tapfd);
diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c
index d3f9d9e..1315fe1 100644
--- a/src/security/security_apparmor.c
+++ b/src/security/security_apparmor.c
@@ -872,6 +872,15 @@ AppArmorSetImageFDLabel(virSecurityManagerPtr mgr,
return reload_profile(mgr, def, fd_path, true);
}
+/* TODO need code here */
+static int
+AppArmorSetTapFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
+ virDomainDefPtr def ATTRIBUTE_UNUSED,
+ int fd ATTRIBUTE_UNUSED)
+{
+ return 0;
+}
+
virSecurityDriver virAppArmorSecurityDriver = {
.privateDataLen = 0,
.name = SECURITY_APPARMOR_NAME,
@@ -908,4 +917,5 @@ virSecurityDriver virAppArmorSecurityDriver = {
.domainRestoreSavedStateLabel = AppArmorRestoreSavedStateLabel,
.domainSetSecurityImageFDLabel = AppArmorSetImageFDLabel,
+ .domainSetSecurityTapFDLabel = AppArmorSetTapFDLabel,
};
diff --git a/src/security/security_dac.c b/src/security/security_dac.c
index f126aa5..9dbf95d 100644
--- a/src/security/security_dac.c
+++ b/src/security/security_dac.c
@@ -1029,6 +1029,14 @@ virSecurityDACSetImageFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
return 0;
}
+static int
+virSecurityDACSetTapFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
+ virDomainDefPtr def ATTRIBUTE_UNUSED,
+ int fd ATTRIBUTE_UNUSED)
+{
+ return 0;
+}
+
static char *virSecurityDACGetMountOptions(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
virDomainDefPtr vm ATTRIBUTE_UNUSED) {
return NULL;
@@ -1070,6 +1078,7 @@ virSecurityDriver virSecurityDriverDAC = {
.domainRestoreSavedStateLabel = virSecurityDACRestoreSavedStateLabel,
.domainSetSecurityImageFDLabel = virSecurityDACSetImageFDLabel,
+ .domainSetSecurityTapFDLabel = virSecurityDACSetTapFDLabel,
.domainGetSecurityMountOptions = virSecurityDACGetMountOptions,
};
diff --git a/src/security/security_driver.h b/src/security/security_driver.h
index 8f52ec5..d49b401 100644
--- a/src/security/security_driver.h
+++ b/src/security/security_driver.h
@@ -95,6 +95,9 @@ typedef int (*virSecurityDomainSecurityVerify) (virSecurityManagerPtr mgr,
typedef int (*virSecurityDomainSetImageFDLabel) (virSecurityManagerPtr mgr,
virDomainDefPtr def,
int fd);
+typedef int (*virSecurityDomainSetTapFDLabel) (virSecurityManagerPtr mgr,
+ virDomainDefPtr def,
+ int fd);
typedef char *(*virSecurityDomainGetMountOptions) (virSecurityManagerPtr mgr,
virDomainDefPtr def);
@@ -134,6 +137,7 @@ struct _virSecurityDriver {
virSecurityDomainRestoreSavedStateLabel domainRestoreSavedStateLabel;
virSecurityDomainSetImageFDLabel domainSetSecurityImageFDLabel;
+ virSecurityDomainSetTapFDLabel domainSetSecurityTapFDLabel;
virSecurityDomainGetMountOptions domainGetSecurityMountOptions;
};
diff --git a/src/security/security_manager.c b/src/security/security_manager.c
index 40c8b7e..d446607 100644
--- a/src/security/security_manager.c
+++ b/src/security/security_manager.c
@@ -469,6 +469,17 @@ int virSecurityManagerSetImageFDLabel(virSecurityManagerPtr mgr,
return -1;
}
+int virSecurityManagerSetTapFDLabel(virSecurityManagerPtr mgr,
+ virDomainDefPtr vm,
+ int fd)
+{
+ if (mgr->drv->domainSetSecurityTapFDLabel)
+ return mgr->drv->domainSetSecurityTapFDLabel(mgr, vm, fd);
+
+ virReportError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
+ return -1;
+}
+
char *virSecurityManagerGetMountOptions(virSecurityManagerPtr mgr,
virDomainDefPtr vm)
{
diff --git a/src/security/security_manager.h b/src/security/security_manager.h
index b3bc191..1fdaf8e 100644
--- a/src/security/security_manager.h
+++ b/src/security/security_manager.h
@@ -105,6 +105,9 @@ int virSecurityManagerVerify(virSecurityManagerPtr mgr,
int virSecurityManagerSetImageFDLabel(virSecurityManagerPtr mgr,
virDomainDefPtr def,
int fd);
+int virSecurityManagerSetTapFDLabel(virSecurityManagerPtr mgr,
+ virDomainDefPtr vm,
+ int fd);
char *virSecurityManagerGetMountOptions(virSecurityManagerPtr mgr,
virDomainDefPtr vm);
virSecurityManagerPtr*
diff --git a/src/security/security_nop.c b/src/security/security_nop.c
index b56971c..86f644b 100644
--- a/src/security/security_nop.c
+++ b/src/security/security_nop.c
@@ -204,7 +204,8 @@ virSecurityDriver virSecurityDriverNop = {
.domainSetSavedStateLabel = virSecurityDomainSetSavedStateLabelNop,
.domainRestoreSavedStateLabel = virSecurityDomainRestoreSavedStateLabelNop,
- .domainSetSecurityImageFDLabel = virSecurityDomainSetFDLabelNop,
+ .domainSetSecurityImageFDLabel = virSecurityDomainSetFDLabelNop,
+ .domainSetSecurityTapFDLabel = virSecurityDomainSetFDLabelNop,
.domainGetSecurityMountOptions = virSecurityDomainGetMountOptionsNop,
};
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 10135ed..0a2a9fe 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -237,6 +237,46 @@ cleanup:
return mcs;
}
+static char *
+virSecuritySELinuxContextAddRange(security_context_t src,
+ security_context_t dst)
+{
+ char *str = NULL;
+ char *ret = NULL;
+ context_t srccon = NULL;
+ context_t dstcon = NULL;
+
+ if (!src || !dst)
+ return ret;
+
+ if (!(srccon = context_new(src)) || !(dstcon = context_new(dst))) {
+ virReportSystemError(errno, "%s",
+ _("unable to allocate security context"));
+ goto cleanup;
+ }
+
+ if (context_range_set(dstcon, context_range_get(srccon)) == -1) {
+ virReportSystemError(errno,
+ _("unable to set security context range '%s'"), dst);
+ goto cleanup;
+ }
+
+ if (!(str = context_str(dstcon))) {
+ virReportSystemError(errno, "%s",
+ _("Unable to format SELinux context"));
+ goto cleanup;
+ }
+
+ if (!(ret = strdup(str))) {
+ virReportOOMError();
+ goto cleanup;
+ }
+
+cleanup:
+ if (srccon) context_free(srccon);
+ if (dstcon) context_free(dstcon);
+ return ret;
+}
static char *
virSecuritySELinuxGenNewContext(const char *basecontext,
@@ -1597,6 +1637,7 @@ virSecuritySELinuxSetSecurityDaemonSocketLabel(virSecurityManagerPtr mgr,
context_t execcon = NULL;
context_t proccon = NULL;
security_context_t scon = NULL;
+ char *str = NULL;
int rc = -1;
secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME);
@@ -1615,13 +1656,6 @@ virSecuritySELinuxSetSecurityDaemonSocketLabel(virSecurityManagerPtr mgr,
goto done;
}
- if ( !(execcon = context_new(secdef->label)) ) {
- virReportSystemError(errno,
- _("unable to allocate socket security context '%s'"),
- secdef->label);
- goto done;
- }
-
if (getcon_raw(&scon) == -1) {
virReportSystemError(errno,
_("unable to get current process context '%s'"),
@@ -1629,26 +1663,13 @@ virSecuritySELinuxSetSecurityDaemonSocketLabel(virSecurityManagerPtr mgr,
goto done;
}
- if ( !(proccon = context_new(scon)) ) {
- virReportSystemError(errno,
- _("unable to set socket security context '%s'"),
- secdef->label);
- goto done;
- }
-
- if (context_range_set(proccon, context_range_get(execcon)) == -1) {
- virReportSystemError(errno,
- _("unable to set socket security context range '%s'"),
- secdef->label);
+ if (!(str = virSecuritySELinuxContextAddRange(secdef->label, scon)))
goto done;
- }
- VIR_DEBUG("Setting VM %s socket context %s",
- def->name, context_str(proccon));
- if (setsockcreatecon_raw(context_str(proccon)) == -1) {
+ VIR_DEBUG("Setting VM %s socket context %s", def->name, str);
+ if (setsockcreatecon_raw(str) == -1) {
virReportSystemError(errno,
- _("unable to set socket security context '%s'"),
- context_str(proccon));
+ _("unable to set socket security context '%s'"), str);
goto done;
}
@@ -1660,6 +1681,7 @@ done:
if (execcon) context_free(execcon);
if (proccon) context_free(proccon);
freecon(scon);
+ VIR_FREE(str);
return rc;
}
@@ -1869,6 +1891,53 @@ virSecuritySELinuxSetImageFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
return virSecuritySELinuxFSetFilecon(fd, secdef->imagelabel);
}
+static int
+virSecuritySELinuxSetTapFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
+ virDomainDefPtr def,
+ int fd)
+{
+ struct stat buf;
+ security_context_t fcon = NULL;
+ virSecurityLabelDefPtr secdef;
+ char *str = NULL;
+ int rc = -1;
+
+ secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME);
+ if (secdef == NULL)
+ return rc;
+
+ if (secdef->label == NULL)
+ return 0;
+
+ if (fstat(fd, &buf) < 0) {
+ virReportSystemError(errno, _("cannot stat tap fd %d"), fd);
+ goto cleanup;
+ }
+
+ if ((buf.st_mode & S_IFMT) != S_IFCHR) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("tap fd %d is not character device"), fd);
+ goto cleanup;
+ }
+
+ if (getContext("/dev/tap.*", buf.st_mode, &fcon) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("cannot lookup default selinux label for tap fd %d"), fd);
+ goto cleanup;
+ }
+
+ if (!(str = virSecuritySELinuxContextAddRange(secdef->label, fcon))) {
+ goto cleanup;
+ } else {
+ rc = virSecuritySELinuxFSetFilecon(fd, str);
+ }
+
+cleanup:
+ freecon(fcon);
+ VIR_FREE(str);
+ return rc;
+}
+
static char *
virSecuritySELinuxGenImageLabel(virSecurityManagerPtr mgr,
virDomainDefPtr def)
@@ -1969,6 +2038,7 @@ virSecurityDriver virSecurityDriverSELinux = {
.domainRestoreSavedStateLabel = virSecuritySELinuxRestoreSavedStateLabel,
.domainSetSecurityImageFDLabel = virSecuritySELinuxSetImageFDLabel,
+ .domainSetSecurityTapFDLabel = virSecuritySELinuxSetTapFDLabel,
.domainGetSecurityMountOptions = virSecuritySELinuxGetSecurityMountOptions,
};
diff --git a/src/security/security_stack.c b/src/security/security_stack.c
index 667448f..24de6f2 100644
--- a/src/security/security_stack.c
+++ b/src/security/security_stack.c
@@ -445,6 +445,23 @@ virSecurityStackSetImageFDLabel(virSecurityManagerPtr mgr,
return rc;
}
+static int
+virSecurityStackSetTapFDLabel(virSecurityManagerPtr mgr,
+ virDomainDefPtr vm,
+ int fd)
+{
+ virSecurityStackDataPtr priv = virSecurityManagerGetPrivateData(mgr);
+ virSecurityStackItemPtr item = priv->itemsHead;
+ int rc = 0;
+
+ for (; item; item = item->next) {
+ if (virSecurityManagerSetTapFDLabel(item->securityManager, vm, fd) < 0)
+ rc = -1;
+ }
+
+ return rc;
+}
+
static char *virSecurityStackGetMountOptions(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
virDomainDefPtr vm ATTRIBUTE_UNUSED) {
return NULL;
@@ -509,6 +526,7 @@ virSecurityDriver virSecurityDriverStack = {
.domainRestoreSavedStateLabel = virSecurityStackRestoreSavedStateLabel,
.domainSetSecurityImageFDLabel = virSecurityStackSetImageFDLabel,
+ .domainSetSecurityTapFDLabel = virSecurityStackSetTapFDLabel,
.domainGetSecurityMountOptions = virSecurityStackGetMountOptions,
};
--
1.7.11.2
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