hyperv: make overlay pages for SynIC

[qemu.git] / qemu-seccomp.c

diff --git a/qemu-seccomp.c b/qemu-seccomp.c
index 148e4c6f24ddf169ca3f73a846e55fad3afe806b..1baa5c69ed0129b2719dd5b7f0cbd78613643b2d 100644 (file)
--- a/qemu-seccomp.c
+++ b/qemu-seccomp.c
@@ -20,6 +20,7 @@
 #include <sys/prctl.h>
 #include <seccomp.h>
 #include "sysemu/seccomp.h"
+#include <linux/seccomp.h>
 
 /* For some architectures (notably ARM) cacheflush is not supported until
  * libseccomp 2.2.3, but configure enforces that we are using a more recent
@@ -34,6 +35,12 @@
 struct QemuSeccompSyscall {
     int32_t num;
     uint8_t set;
+    uint8_t narg;
+    const struct scmp_arg_cmp *arg_cmp;
+};
+
+const struct scmp_arg_cmp sched_setscheduler_arg[] = {
+    SCMP_A1(SCMP_CMP_NE, SCHED_IDLE)
 };
 
 static const struct QemuSeccompSyscall blacklist[] = {
@@ -92,7 +99,8 @@ static const struct QemuSeccompSyscall blacklist[] = {
     { SCMP_SYS(setpriority),            QEMU_SECCOMP_SET_RESOURCECTL },
     { SCMP_SYS(sched_setparam),         QEMU_SECCOMP_SET_RESOURCECTL },
     { SCMP_SYS(sched_getparam),         QEMU_SECCOMP_SET_RESOURCECTL },
-    { SCMP_SYS(sched_setscheduler),     QEMU_SECCOMP_SET_RESOURCECTL },
+    { SCMP_SYS(sched_setscheduler),     QEMU_SECCOMP_SET_RESOURCECTL,
+      ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
     { SCMP_SYS(sched_getscheduler),     QEMU_SECCOMP_SET_RESOURCECTL },
     { SCMP_SYS(sched_setaffinity),      QEMU_SECCOMP_SET_RESOURCECTL },
     { SCMP_SYS(sched_getaffinity),      QEMU_SECCOMP_SET_RESOURCECTL },
@@ -100,12 +108,40 @@ static const struct QemuSeccompSyscall blacklist[] = {
     { SCMP_SYS(sched_get_priority_min), QEMU_SECCOMP_SET_RESOURCECTL },
 };
 
+static inline __attribute__((unused)) int
+qemu_seccomp(unsigned int operation, unsigned int flags, void *args)
+{
+#ifdef __NR_seccomp
+    return syscall(__NR_seccomp, operation, flags, args);
+#else
+    errno = ENOSYS;
+    return -1;
+#endif
+}
+
+static uint32_t qemu_seccomp_get_kill_action(void)
+{
+#if defined(SECCOMP_GET_ACTION_AVAIL) && defined(SCMP_ACT_KILL_PROCESS) && \
+    defined(SECCOMP_RET_KILL_PROCESS)
+    {
+        uint32_t action = SECCOMP_RET_KILL_PROCESS;
+
+        if (qemu_seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &action) == 0) {
+            return SCMP_ACT_KILL_PROCESS;
+        }
+    }
+#endif
+
+    return SCMP_ACT_TRAP;
+}
+
 
 static int seccomp_start(uint32_t seccomp_opts)
 {
     int rc = 0;
     unsigned int i = 0;
     scmp_filter_ctx ctx;
+    uint32_t action = qemu_seccomp_get_kill_action();
 
     ctx = seccomp_init(SCMP_ACT_ALLOW);
     if (ctx == NULL) {
@@ -113,12 +149,18 @@ static int seccomp_start(uint32_t seccomp_opts)
         goto seccomp_return;
     }
 
+    rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_TSYNC, 1);
+    if (rc != 0) {
+        goto seccomp_return;
+    }
+
     for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
         if (!(seccomp_opts & blacklist[i].set)) {
             continue;
         }
 
-        rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
+        rc = seccomp_rule_add_array(ctx, action, blacklist[i].num,
+                                    blacklist[i].narg, blacklist[i].arg_cmp);
         if (rc < 0) {
             goto seccomp_return;
         }
@@ -240,7 +282,24 @@ static QemuOptsList qemu_sandbox_opts = {
 
 static void seccomp_register(void)
 {
-    qemu_add_opts(&qemu_sandbox_opts);
+    bool add = false;
+
+    /* FIXME: use seccomp_api_get() >= 2 check when released */
+
+#if defined(SECCOMP_FILTER_FLAG_TSYNC)
+    int check;
+
+    /* check host TSYNC capability, it returns errno == ENOSYS if unavailable */
+    check = qemu_seccomp(SECCOMP_SET_MODE_FILTER,
+                         SECCOMP_FILTER_FLAG_TSYNC, NULL);
+    if (check < 0 && errno == EFAULT) {
+        add = true;
+    }
+#endif
+
+    if (add) {
+        qemu_add_opts(&qemu_sandbox_opts);
+    }
 }
 opts_init(seccomp_register);
 #endif