Now that ioctl(2) is allowed in capability mode and we can limit ioctls for the

given descriptors, use Capsicum sandboxing for hastd in primary and secondary
modes. Allow for DIOCGDELETE and DIOCGFLUSH ioctls on provider descriptor and
for G_GATE_CMD_MODIFY, G_GATE_CMD_START, G_GATE_CMD_DONE and G_GATE_CMD_DESTROY
on GEOM Gate descriptor.

Sponsored by:	The FreeBSD Foundation

1 files changed, 48 insertions, 16 deletions

diff --git a/sbin/hastd/subr.c b/sbin/hastd/subr.c
index ae6f984..440061e 100644
--- a/sbin/hastd/subr.c
+++ b/sbin/hastd/subr.c
@@ -31,14 +31,15 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#ifdef HAVE_CAPSICUM
-#include <sys/capability.h>
-#endif
 #include <sys/param.h>
 #include <sys/disk.h>
 #include <sys/ioctl.h>
 #include <sys/jail.h>
 #include <sys/stat.h>
+#ifdef HAVE_CAPSICUM
+#include <sys/capability.h>
+#include <geom/gate/g_gate.h>
+#endif
 
 #include <errno.h>
 #include <fcntl.h>
@@ -224,22 +225,53 @@ drop_privs(const struct hast_resource *res)
 		return (-1);
 	}
 
-	/*
-	 * Until capsicum doesn't allow ioctl(2) we cannot use it to sandbox
-	 * primary and secondary worker processes, as primary uses GGATE
-	 * ioctls and secondary uses ioctls to handle BIO_DELETE and BIO_FLUSH.
-	 * For now capsicum is only used to sandbox hastctl.
-	 */
 #ifdef HAVE_CAPSICUM
-	if (res == NULL) {
-		capsicum = (cap_enter() == 0);
-		if (!capsicum) {
-			pjdlog_common(LOG_DEBUG, 1, errno,
-			    "Unable to sandbox using capsicum");
+	capsicum = (cap_enter() == 0);
+	if (!capsicum) {
+		pjdlog_common(LOG_DEBUG, 1, errno,
+		    "Unable to sandbox using capsicum");
+	} else if (res != NULL) {
+		static const unsigned long geomcmds[] = {
+		    DIOCGDELETE,
+		    DIOCGFLUSH
+		};
+
+		PJDLOG_ASSERT(res->hr_role == HAST_ROLE_PRIMARY ||
+		    res->hr_role == HAST_ROLE_SECONDARY);
+
+		if (cap_rights_limit(res->hr_localfd,
+		    CAP_FLOCK | CAP_IOCTL | CAP_PREAD | CAP_PWRITE) == -1) {
+			pjdlog_errno(LOG_ERR,
+			    "Unable to limit capability rights on local descriptor");
+		}
+		if (cap_ioctls_limit(res->hr_localfd, geomcmds,
+		    sizeof(geomcmds) / sizeof(geomcmds[0])) == -1) {
+			pjdlog_errno(LOG_ERR,
+			    "Unable to limit allowed GEOM ioctls");
 		}
-	} else
+
+		if (res->hr_role == HAST_ROLE_PRIMARY) {
+			static const unsigned long ggatecmds[] = {
+			    G_GATE_CMD_MODIFY,
+			    G_GATE_CMD_START,
+			    G_GATE_CMD_DONE,
+			    G_GATE_CMD_DESTROY
+			};
+
+			if (cap_rights_limit(res->hr_ggatefd, CAP_IOCTL) == -1) {
+				pjdlog_errno(LOG_ERR,
+				    "Unable to limit capability rights to CAP_IOCTL on ggate descriptor");
+			}
+			if (cap_ioctls_limit(res->hr_ggatefd, ggatecmds,
+			    sizeof(ggatecmds) / sizeof(ggatecmds[0])) == -1) {
+				pjdlog_errno(LOG_ERR,
+				    "Unable to limit allowed ggate ioctls");
+			}
+		}
+	}
+#else
+	capsicum = false;
 #endif
-		capsicum = false;
 
 	/*
 	 * Better be sure that everything succeeded.