X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=qemu-seccomp.c;h=e0a1829b3ddc9732f357179b9c23ce4b48703efb;hb=79b9d4bde7db3f760851217b329c68a883184c6b;hp=4729eb107f8ff169a1011dd96264fd2d82910e46;hpb=235c82acca0491465e94be3cae2583b42d37c859;p=mirror_qemu.git

diff --git a/qemu-seccomp.c b/qemu-seccomp.c
index 4729eb107f..e0a1829b3d 100644
--- a/qemu-seccomp.c
+++ b/qemu-seccomp.c
@@ -12,11 +12,12 @@
  * Contributions after 2012-01-13 are licensed under the terms of the
  * GNU GPL, version 2 or (at your option) any later version.
  */
+
 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "qemu/config-file.h"
 #include "qemu/option.h"
 #include "qemu/module.h"
-#include "qemu/error-report.h"
 #include <sys/prctl.h>
 #include <seccomp.h>
 #include "sysemu/seccomp.h"
@@ -40,7 +41,8 @@ struct QemuSeccompSyscall {
 };
 
 const struct scmp_arg_cmp sched_setscheduler_arg[] = {
-    SCMP_A1(SCMP_CMP_NE, SCHED_IDLE)
+    /* was SCMP_A1(SCMP_CMP_NE, SCHED_IDLE), but expanded due to GCC 4.x bug */
+    { .arg = 1, .op = SCMP_CMP_NE, .datum_a = SCHED_IDLE }
 };
 
 static const struct QemuSeccompSyscall blacklist[] = {
@@ -119,58 +121,84 @@ qemu_seccomp(unsigned int operation, unsigned int flags, void *args)
 #endif
 }
 
-static uint32_t qemu_seccomp_get_kill_action(void)
+static uint32_t qemu_seccomp_get_action(int set)
 {
+    switch (set) {
+    case QEMU_SECCOMP_SET_DEFAULT:
+    case QEMU_SECCOMP_SET_OBSOLETE:
+    case QEMU_SECCOMP_SET_PRIVILEGED:
+    case QEMU_SECCOMP_SET_SPAWN: {
 #if defined(SECCOMP_GET_ACTION_AVAIL) && defined(SCMP_ACT_KILL_PROCESS) && \
     defined(SECCOMP_RET_KILL_PROCESS)
-    {
-        uint32_t action = SECCOMP_RET_KILL_PROCESS;
+        static int kill_process = -1;
+        if (kill_process == -1) {
+            uint32_t action = SECCOMP_RET_KILL_PROCESS;
 
-        if (qemu_seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &action) == 0) {
+            if (qemu_seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &action) == 0) {
+                kill_process = 1;
+            }
+            kill_process = 0;
+        }
+        if (kill_process == 1) {
             return SCMP_ACT_KILL_PROCESS;
         }
-    }
 #endif
+        return SCMP_ACT_TRAP;
+    }
+
+    case QEMU_SECCOMP_SET_RESOURCECTL:
+        return SCMP_ACT_ERRNO(EPERM);
 
-    return SCMP_ACT_TRAP;
+    default:
+        g_assert_not_reached();
+    }
 }
 
 
-static int seccomp_start(uint32_t seccomp_opts)
+static int seccomp_start(uint32_t seccomp_opts, Error **errp)
 {
-    int rc = 0;
+    int rc = -1;
     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) {
-        rc = -1;
+        error_setg(errp, "failed to initialize seccomp context");
         goto seccomp_return;
     }
 
     rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_TSYNC, 1);
     if (rc != 0) {
+        error_setg_errno(errp, -rc,
+                         "failed to set seccomp thread synchronization");
         goto seccomp_return;
     }
 
     for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
+        uint32_t action;
         if (!(seccomp_opts & blacklist[i].set)) {
             continue;
         }
 
+        action = qemu_seccomp_get_action(blacklist[i].set);
         rc = seccomp_rule_add_array(ctx, action, blacklist[i].num,
                                     blacklist[i].narg, blacklist[i].arg_cmp);
         if (rc < 0) {
+            error_setg_errno(errp, -rc,
+                             "failed to add seccomp blacklist rules");
             goto seccomp_return;
         }
     }
 
     rc = seccomp_load(ctx);
+    if (rc < 0) {
+        error_setg_errno(errp, -rc,
+                         "failed to load seccomp syscall filter in kernel");
+    }
 
   seccomp_return:
     seccomp_release(ctx);
-    return rc;
+    return rc < 0 ? -1 : 0;
 }
 
 #ifdef CONFIG_SECCOMP
@@ -190,7 +218,7 @@ int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
                  * to provide a little bit of consistency for
                  * the command line */
             } else {
-                error_report("invalid argument for obsolete");
+                error_setg(errp, "invalid argument for obsolete");
                 return -1;
             }
         }
@@ -205,14 +233,13 @@ int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
                 /* calling prctl directly because we're
                  * not sure if host has CAP_SYS_ADMIN set*/
                 if (prctl(PR_SET_NO_NEW_PRIVS, 1)) {
-                    error_report("failed to set no_new_privs "
-                                 "aborting");
+                    error_setg(errp, "failed to set no_new_privs aborting");
                     return -1;
                 }
             } else if (g_str_equal(value, "allow")) {
                 /* default value */
             } else {
-                error_report("invalid argument for elevateprivileges");
+                error_setg(errp, "invalid argument for elevateprivileges");
                 return -1;
             }
         }
@@ -224,7 +251,7 @@ int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
             } else if (g_str_equal(value, "allow")) {
                 /* default value */
             } else {
-                error_report("invalid argument for spawn");
+                error_setg(errp, "invalid argument for spawn");
                 return -1;
             }
         }
@@ -236,14 +263,12 @@ int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
             } else if (g_str_equal(value, "allow")) {
                 /* default value */
             } else {
-                error_report("invalid argument for resourcecontrol");
+                error_setg(errp, "invalid argument for resourcecontrol");
                 return -1;
             }
         }
 
-        if (seccomp_start(seccomp_opts) < 0) {
-            error_report("failed to install seccomp syscall filter "
-                         "in the kernel");
+        if (seccomp_start(seccomp_opts, errp) < 0) {
             return -1;
         }
     }
@@ -282,7 +307,24 @@ 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