From 8296437564980199342f4fd9f2c85312570ba060 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Tue, 27 Dec 2016 15:28:25 +0100

Subject: [PATCH] seccomp: rework seccomp code, to improve compat with some

 archs

This substantially reworks the seccomp code, to ensure better

compatibility with some architectures, including i386.

So far we relied on libseccomp's internal handling of the multiple

syscall ABIs supported on Linux. This is problematic however, as it does

not define clear semantics if an ABI is not able to support specific

seccomp rules we install.

This rework hence changes a couple of things:

- We no longer use seccomp_rule_add(), but only

  seccomp_rule_add_exact(), and fail the installation of a filter if the

  architecture doesn't support it.

- We no longer rely on adding multiple syscall architectures to a single filter,

  but instead install a separate filter for each syscall architecture

  supported. This way, we can install a strict filter for x86-64, while

  permitting a less strict filter for i386.

- All high-level filter additions are now moved from execute.c to

  seccomp-util.c, so that we can test them independently of the service

  execution logic.

- Tests have been added for all types of our seccomp filters.

- SystemCallFilters= and SystemCallArchitectures= are now implemented in

  independent filters and installation logic, as they semantically are

  very much independent of each other.

Fixes: #4575

(cherry picked from commit 469830d1426a91e0897c321fdc8ee428f0a750c1)

---

 src/core/execute.c          | 466 ++++++++----------------------

 src/core/main.c             |  34 +--

 src/nspawn/nspawn-seccomp.c | 117 ++++----

 src/shared/seccomp-util.c   | 670 +++++++++++++++++++++++++++++++++++---------

 src/shared/seccomp-util.h   |  25 +-

 src/test/test-execute.c     |   1 +

 src/test/test-seccomp.c     | 272 +++++++++++++++++-

 7 files changed, 1016 insertions(+), 569 deletions(-)

diff --git a/src/core/execute.c b/src/core/execute.c

index 59ce0774c4..2dfd43a8f2 100644

--- a/src/core/execute.c

+++ b/src/core/execute.c

@@ -1184,6 +1184,41 @@ static void rename_process_from_path(const char *path) {

         rename_process(process_name);

 }

+static bool context_has_address_families(const ExecContext *c) {

+        assert(c);

+

+        return c->address_families_whitelist ||

+                !set_isempty(c->address_families);

+}

+

+static bool context_has_syscall_filters(const ExecContext *c) {

+        assert(c);

+

+        return c->syscall_whitelist ||

+                !set_isempty(c->syscall_filter);

+}

+

+static bool context_has_no_new_privileges(const ExecContext *c) {

+        assert(c);

+

+        if (c->no_new_privileges)

+                return true;

+

+        if (have_effective_cap(CAP_SYS_ADMIN)) /* if we are privileged, we don't need NNP */

+                return false;

+

+        /* We need NNP if we have any form of seccomp and are unprivileged */

+        return context_has_address_families(c) ||

+                c->memory_deny_write_execute ||

+                c->restrict_realtime ||

+                exec_context_restrict_namespaces_set(c) ||

+                c->protect_kernel_tunables ||

+                c->protect_kernel_modules ||

+                c->private_devices ||

+                context_has_syscall_filters(c) ||

+                !set_isempty(c->syscall_archs);

+}

+

 #ifdef HAVE_SECCOMP

 static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {

@@ -1197,344 +1232,131 @@ static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {

         return true;

 }

-static int apply_seccomp(const Unit* u, const ExecContext *c) {

-        uint32_t negative_action, action;

-        scmp_filter_ctx seccomp;

-        Iterator i;

-        void *id;

-        int r;

+static int apply_syscall_filter(const Unit* u, const ExecContext *c) {

+        uint32_t negative_action, default_action, action;

+        assert(u);

         assert(c);

-        if (skip_seccomp_unavailable(u, "syscall filtering"))

+        if (!context_has_syscall_filters(c))

+                return 0;

+

+        if (skip_seccomp_unavailable(u, "SystemCallFilter="))

                 return 0;

         negative_action = c->syscall_errno == 0 ? SCMP_ACT_KILL : SCMP_ACT_ERRNO(c->syscall_errno);

-        seccomp = seccomp_init(c->syscall_whitelist ? negative_action : SCMP_ACT_ALLOW);

-        if (!seccomp)

-                return -ENOMEM;

-

-        if (c->syscall_archs) {

-

-                SET_FOREACH(id, c->syscall_archs, i) {

-                        r = seccomp_arch_add(seccomp, PTR_TO_UINT32(id) - 1);

-                        if (r == -EEXIST)

-                                continue;

-                        if (r < 0)

-                                goto finish;

-                }

-

+        if (c->syscall_whitelist) {

+                default_action = negative_action;

+                action = SCMP_ACT_ALLOW;

         } else {

-                r = seccomp_add_secondary_archs(seccomp);

-                if (r < 0)

-                        goto finish;

+                default_action = SCMP_ACT_ALLOW;

+                action = negative_action;

         }

-        action = c->syscall_whitelist ? SCMP_ACT_ALLOW : negative_action;

-        SET_FOREACH(id, c->syscall_filter, i) {

-                r = seccomp_rule_add(seccomp, action, PTR_TO_INT(id) - 1, 0);

-                if (r < 0)

-                        goto finish;

-        }

+        return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_filter, action);

+}

+

+static int apply_syscall_archs(const Unit *u, const ExecContext *c) {

+        assert(u);

+        assert(c);

-        r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);

-        if (r < 0)

-                goto finish;

+        if (set_isempty(c->syscall_archs))

+                return 0;

-        r = seccomp_load(seccomp);

+        if (skip_seccomp_unavailable(u, "SystemCallArchitectures="))

+                return 0;

-finish:

-        seccomp_release(seccomp);

-        return r;

+        return seccomp_restrict_archs(c->syscall_archs);

 }

 static int apply_address_families(const Unit* u, const ExecContext *c) {

-        scmp_filter_ctx seccomp;

-        Iterator i;

-        int r;

-

+        assert(u);

         assert(c);

+        if (!context_has_address_families(c))

+                return 0;

+

         if (skip_seccomp_unavailable(u, "RestrictAddressFamilies="))

                 return 0;

-        r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);

-        if (r < 0)

-                return r;

-

-        if (c->address_families_whitelist) {

-                int af, first = 0, last = 0;

-                void *afp;

-

-                /* If this is a whitelist, we first block the address

-                 * families that are out of range and then everything

-                 * that is not in the set. First, we find the lowest

-                 * and highest address family in the set. */

-

-                SET_FOREACH(afp, c->address_families, i) {

-                        af = PTR_TO_INT(afp);

-

-                        if (af <= 0 || af >= af_max())

-                                continue;

-

-                        if (first == 0 || af < first)

-                                first = af;

-

-                        if (last == 0 || af > last)

-                                last = af;

-                }

-

-                assert((first == 0) == (last == 0));

-

-                if (first == 0) {

-

-                        /* No entries in the valid range, block everything */

-                        r = seccomp_rule_add(

-                                        seccomp,

-                                        SCMP_ACT_ERRNO(EPROTONOSUPPORT),

-                                        SCMP_SYS(socket),

-                                        0);

-                        if (r < 0)

-                                goto finish;

-

-                } else {

-

-                        /* Block everything below the first entry */

-                        r = seccomp_rule_add(

-                                        seccomp,

-                                        SCMP_ACT_ERRNO(EPROTONOSUPPORT),

-                                        SCMP_SYS(socket),

-                                        1,

-                                        SCMP_A0(SCMP_CMP_LT, first));

-                        if (r < 0)

-                                goto finish;

-

-                        /* Block everything above the last entry */

-                        r = seccomp_rule_add(

-                                        seccomp,

-                                        SCMP_ACT_ERRNO(EPROTONOSUPPORT),

-                                        SCMP_SYS(socket),

-                                        1,

-                                        SCMP_A0(SCMP_CMP_GT, last));

-                        if (r < 0)

-                                goto finish;

-

-                        /* Block everything between the first and last

-                         * entry */

-                        for (af = 1; af < af_max(); af++) {

-

-                                if (set_contains(c->address_families, INT_TO_PTR(af)))

-                                        continue;

-

-                                r = seccomp_rule_add(

-                                                seccomp,

-                                                SCMP_ACT_ERRNO(EPROTONOSUPPORT),

-                                                SCMP_SYS(socket),

-                                                1,

-                                                SCMP_A0(SCMP_CMP_EQ, af));

-                                if (r < 0)

-                                        goto finish;

-                        }

-                }

-

-        } else {

-                void *af;

-

-                /* If this is a blacklist, then generate one rule for

-                 * each address family that are then combined in OR

-                 * checks. */

-

-                SET_FOREACH(af, c->address_families, i) {

-

-                        r = seccomp_rule_add(

-                                        seccomp,

-                                        SCMP_ACT_ERRNO(EPROTONOSUPPORT),

-                                        SCMP_SYS(socket),

-                                        1,

-                                        SCMP_A0(SCMP_CMP_EQ, PTR_TO_INT(af)));

-                        if (r < 0)

-                                goto finish;

-                }

-        }

-

-        r = seccomp_load(seccomp);

-

-finish:

-        seccomp_release(seccomp);

-        return r;

+        return seccomp_restrict_address_families(c->address_families, c->address_families_whitelist);

 }

 static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c) {

-        scmp_filter_ctx seccomp;

-        int r;

-

+        assert(u);

         assert(c);

+        if (!c->memory_deny_write_execute)

+                return 0;

+

         if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute="))

                 return 0;

-        r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);

-        if (r < 0)

-                return r;

-

-        r = seccomp_rule_add(

-                        seccomp,

-                        SCMP_ACT_ERRNO(EPERM),

-                        SCMP_SYS(mmap),

-                        1,

-                        SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC|PROT_WRITE, PROT_EXEC|PROT_WRITE));

-        if (r < 0)

-                goto finish;

-

-        r = seccomp_rule_add(

-                        seccomp,

-                        SCMP_ACT_ERRNO(EPERM),

-                        SCMP_SYS(mprotect),

-                        1,

-                        SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC, PROT_EXEC));

-        if (r < 0)

-                goto finish;

-

-        r = seccomp_rule_add(

-                        seccomp,

-                        SCMP_ACT_ERRNO(EPERM),

-                        SCMP_SYS(shmat),

-                        1,

-                        SCMP_A2(SCMP_CMP_MASKED_EQ, SHM_EXEC, SHM_EXEC));

-        if (r < 0)

-                goto finish;

-

-        r = seccomp_load(seccomp);

-

-finish:

-        seccomp_release(seccomp);

-        return r;

+        return seccomp_memory_deny_write_execute();

 }

 static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {

-        static const int permitted_policies[] = {

-                SCHED_OTHER,

-                SCHED_BATCH,

-                SCHED_IDLE,

-        };

-

-        scmp_filter_ctx seccomp;

-        unsigned i;

-        int r, p, max_policy = 0;

-

+        assert(u);

         assert(c);

+        if (!c->restrict_realtime)

+                return 0;

+

         if (skip_seccomp_unavailable(u, "RestrictRealtime="))

                 return 0;

-        r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);

-        if (r < 0)

-                return r;

-

-        /* Determine the highest policy constant we want to allow */

-        for (i = 0; i < ELEMENTSOF(permitted_policies); i++)

-                if (permitted_policies[i] > max_policy)

-                        max_policy = permitted_policies[i];

-

-        /* Go through all policies with lower values than that, and block them -- unless they appear in the

-         * whitelist. */

-        for (p = 0; p < max_policy; p++) {

-                bool good = false;

-

-                /* Check if this is in the whitelist. */

-                for (i = 0; i < ELEMENTSOF(permitted_policies); i++)

-                        if (permitted_policies[i] == p) {

-                                good = true;

-                                break;

-                        }

-

-                if (good)

-                        continue;

-

-                /* Deny this policy */

-                r = seccomp_rule_add(

-                                seccomp,

-                                SCMP_ACT_ERRNO(EPERM),

-                                SCMP_SYS(sched_setscheduler),

-                                1,

-                                SCMP_A1(SCMP_CMP_EQ, p));

-                if (r < 0)

-                        goto finish;

-        }

-

-        /* Blacklist all other policies, i.e. the ones with higher values. Note that all comparisons are unsigned here,

-         * hence no need no check for < 0 values. */

-        r = seccomp_rule_add(

-                        seccomp,

-                        SCMP_ACT_ERRNO(EPERM),

-                        SCMP_SYS(sched_setscheduler),

-                        1,

-                        SCMP_A1(SCMP_CMP_GT, max_policy));

-        if (r < 0)

-                goto finish;

-

-        r = seccomp_load(seccomp);

-

-finish:

-        seccomp_release(seccomp);

-        return r;

+        return seccomp_restrict_realtime();

 }

 static int apply_protect_sysctl(const Unit *u, const ExecContext *c) {

-        scmp_filter_ctx seccomp;

-        int r;

-

+        assert(u);

         assert(c);

         /* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but

          * let's protect even those systems where this is left on in the kernel. */

+        if (!c->protect_kernel_tunables)

+                return 0;

+

         if (skip_seccomp_unavailable(u, "ProtectKernelTunables="))

                 return 0;

-        r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);

-        if (r < 0)

-                return r;

-

-        r = seccomp_rule_add(

-                        seccomp,

-                        SCMP_ACT_ERRNO(EPERM),

-                        SCMP_SYS(_sysctl),

-                        0);

-        if (r < 0)

-                goto finish;

-

-        r = seccomp_load(seccomp);

-

-finish:

-        seccomp_release(seccomp);

-        return r;

+        return seccomp_protect_sysctl();

 }

 static int apply_protect_kernel_modules(const Unit *u, const ExecContext *c) {

+        assert(u);

         assert(c);

         /* Turn off module syscalls on ProtectKernelModules=yes */

+        if (!c->protect_kernel_modules)

+                return 0;

+

         if (skip_seccomp_unavailable(u, "ProtectKernelModules="))

                 return 0;

-        return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM));

+        return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM));

 }

 static int apply_private_devices(const Unit *u, const ExecContext *c) {

+        assert(u);

         assert(c);

         /* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */

+        if (!c->private_devices)

+                return 0;

+

         if (skip_seccomp_unavailable(u, "PrivateDevices="))

                 return 0;

-        return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM));

+        return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM));

 }

 static int apply_restrict_namespaces(Unit *u, const ExecContext *c) {

+        assert(u);

         assert(c);

         if (!exec_context_restrict_namespaces_set(c))

@@ -2168,40 +1990,6 @@ static int close_remaining_fds(

         return close_all_fds(dont_close, n_dont_close);

 }

-static bool context_has_address_families(const ExecContext *c) {

-        assert(c);

-

-        return c->address_families_whitelist ||

-                !set_isempty(c->address_families);

-}

-

-static bool context_has_syscall_filters(const ExecContext *c) {

-        assert(c);

-

-        return c->syscall_whitelist ||

-                !set_isempty(c->syscall_filter) ||

-                !set_isempty(c->syscall_archs);

-}

-

-static bool context_has_no_new_privileges(const ExecContext *c) {

-        assert(c);

-

-        if (c->no_new_privileges)

-                return true;

-

-        if (have_effective_cap(CAP_SYS_ADMIN)) /* if we are privileged, we don't need NNP */

-                return false;

-

-        return context_has_address_families(c) || /* we need NNP if we have any form of seccomp and are unprivileged */

-                c->memory_deny_write_execute ||

-                c->restrict_realtime ||

-                exec_context_restrict_namespaces_set(c) ||

-                c->protect_kernel_tunables ||

-                c->protect_kernel_modules ||

-                c->private_devices ||

-                context_has_syscall_filters(c);

-}

-

 static int send_user_lookup(

                 Unit *unit,

                 int user_lookup_fd,

@@ -2753,28 +2541,22 @@ static int exec_child(

                         }

 #ifdef HAVE_SECCOMP

-                if (context_has_address_families(context)) {

-                        r = apply_address_families(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_ADDRESS_FAMILIES;

-                                return r;

-                        }

+                r = apply_address_families(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_ADDRESS_FAMILIES;

+                        return r;

                 }

-                if (context->memory_deny_write_execute) {

-                        r = apply_memory_deny_write_execute(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_SECCOMP;

-                                return r;

-                        }

+                r = apply_memory_deny_write_execute(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

                 }

-                if (context->restrict_realtime) {

-                        r = apply_restrict_realtime(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_SECCOMP;

-                                return r;

-                        }

+                r = apply_restrict_realtime(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

                 }

                 r = apply_restrict_namespaces(unit, context);

@@ -2783,38 +2565,36 @@ static int exec_child(

                         return r;

                 }

-                if (context->protect_kernel_tunables) {

-                        r = apply_protect_sysctl(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_SECCOMP;

-                                return r;

-                        }

+                r = apply_protect_sysctl(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

                 }

-                if (context->protect_kernel_modules) {

-                        r = apply_protect_kernel_modules(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_SECCOMP;

-                                return r;

-                        }

+                r = apply_protect_kernel_modules(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

                 }

-                if (context->private_devices) {

-                        r = apply_private_devices(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_SECCOMP;

-                                return r;

-                        }

+                r = apply_private_devices(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

+                }

+

+                r = apply_syscall_archs(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

                 }

                 /* This really should remain the last step before the execve(), to make sure our own code is unaffected

                  * by the filter as little as possible. */

-                if (context_has_syscall_filters(context)) {

-                        r = apply_seccomp(unit, context);

-                        if (r < 0) {

-                                *exit_status = EXIT_SECCOMP;

-                                return r;

-                        }

+                r = apply_syscall_filter(unit, context);

+                if (r < 0) {

+                        *exit_status = EXIT_SECCOMP;

+                        return r;

                 }

 #endif

         }

diff --git a/src/core/main.c b/src/core/main.c

index 94602611a7..fc1ae123a8 100644

--- a/src/core/main.c

+++ b/src/core/main.c

@@ -1185,44 +1185,16 @@ oom:

 static int enforce_syscall_archs(Set *archs) {

 #ifdef HAVE_SECCOMP

-        scmp_filter_ctx *seccomp;

-        Iterator i;

-        void *id;

         int r;

         if (!is_seccomp_available())

                 return 0;

-        seccomp = seccomp_init(SCMP_ACT_ALLOW);

-        if (!seccomp)

-                return log_oom();

-

-        SET_FOREACH(id, arg_syscall_archs, i) {

-                r = seccomp_arch_add(seccomp, PTR_TO_UINT32(id) - 1);

-                if (r == -EEXIST)

-                        continue;

-                if (r < 0) {

-                        log_error_errno(r, "Failed to add architecture to seccomp: %m");

-                        goto finish;

-                }

-        }

-

-        r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);

-        if (r < 0) {

-                log_error_errno(r, "Failed to unset NO_NEW_PRIVS: %m");

-                goto finish;

-        }

-

-        r = seccomp_load(seccomp);

+        r = seccomp_restrict_archs(arg_syscall_archs);

         if (r < 0)

-                log_error_errno(r, "Failed to add install architecture seccomp: %m");

-

-finish:

-        seccomp_release(seccomp);

-        return r;

-#else

-        return 0;

+                return log_error_errno(r, "Failed to enforce system call architecture restrication: %m");

 #endif

+        return 0;

 }

 static int status_welcome(void) {

diff --git a/src/nspawn/nspawn-seccomp.c b/src/nspawn/nspawn-seccomp.c

index 03a397d30c..72ecc51b16 100644

--- a/src/nspawn/nspawn-seccomp.c

+++ b/src/nspawn/nspawn-seccomp.c

@@ -26,20 +26,21 @@

 #include <seccomp.h>

 #endif

+#include "alloc-util.h"

 #include "log.h"

-

-#ifdef HAVE_SECCOMP

-#include "seccomp-util.h"

-#endif

-

 #include "nspawn-seccomp.h"

+#ifdef HAVE_SECCOMP

+#include "seccomp-util.h"

+#endif

+#include "string-util.h"

 #ifdef HAVE_SECCOMP

-static int seccomp_add_default_syscall_filter(scmp_filter_ctx ctx,

-                                              uint64_t cap_list_retain) {

-        unsigned i;

-        int r;

+static int seccomp_add_default_syscall_filter(

+                scmp_filter_ctx ctx,

+                uint32_t arch,

+                uint64_t cap_list_retain) {

+

         static const struct {

                 uint64_t capability;

                 int syscall_num;

@@ -111,23 +112,29 @@ static int seccomp_add_default_syscall_filter(scmp_filter_ctx ctx,

                 { CAP_SYS_TIME,   SCMP_SYS(settimeofday)        },

                 { CAP_SYS_TIME,   SCMP_SYS(stime)               },

         };

+        unsigned i;

+        int r, c = 0;

         for (i = 0; i < ELEMENTSOF(blacklist); i++) {

                 if (blacklist[i].capability != 0 && (cap_list_retain & (1ULL << blacklist[i].capability)))

                         continue;

-                r = seccomp_rule_add(ctx, SCMP_ACT_ERRNO(EPERM), blacklist[i].syscall_num, 0);

-                if (r == -EFAULT)

-                        continue; /* unknown syscall */

-                if (r < 0)

-                        return log_error_errno(r, "Failed to block syscall: %m");

+                r = seccomp_rule_add_exact(ctx, SCMP_ACT_ERRNO(EPERM), blacklist[i].syscall_num, 0);

+                if (r < 0) {

+                        /* If the system call is not known on this architecture, then that's fine, let's ignore it */

+                        _cleanup_free_ char *n = NULL;

+

+                        n = seccomp_syscall_resolve_num_arch(arch, blacklist[i].syscall_num);

+                        log_debug_errno(r, "Failed to add rule for system call %s, ignoring: %m", strna(n));

+                } else

+                        c++;

         }

-        return 0;

+        return c;

 }

 int setup_seccomp(uint64_t cap_list_retain) {

-        scmp_filter_ctx seccomp;

+        uint32_t arch;

         int r;

         if (!is_seccomp_available()) {

@@ -135,45 +142,51 @@ int setup_seccomp(uint64_t cap_list_retain) {

                 return 0;

         }

-        r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);

-        if (r < 0)

-                return log_error_errno(r, "Failed to allocate seccomp object: %m");

-

-        r = seccomp_add_default_syscall_filter(seccomp, cap_list_retain);

-        if (r < 0)

-                goto finish;

-

-        /*

-           Audit is broken in containers, much of the userspace audit

-           hookup will fail if running inside a container. We don't

-           care and just turn off creation of audit sockets.

-

-           This will make socket(AF_NETLINK, *, NETLINK_AUDIT) fail

-           with EAFNOSUPPORT which audit userspace uses as indication

-           that audit is disabled in the kernel.

-         */

-

-        r = seccomp_rule_add(

-                        seccomp,

-                        SCMP_ACT_ERRNO(EAFNOSUPPORT),

-                        SCMP_SYS(socket),

-                        2,

-                        SCMP_A0(SCMP_CMP_EQ, AF_NETLINK),

-                        SCMP_A2(SCMP_CMP_EQ, NETLINK_AUDIT));

-        if (r < 0) {

-                log_error_errno(r, "Failed to add audit seccomp rule: %m");

-                goto finish;

-        }

+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {

+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;

+                int n;

+

+                log_debug("Operating on architecture: %s", seccomp_arch_to_string(arch));

+

+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);

+                if (r < 0)

+                        return log_error_errno(r, "Failed to allocate seccomp object: %m");

+

+                n = seccomp_add_default_syscall_filter(seccomp, arch, cap_list_retain);

+                if (n < 0)

+                        return n;

+

+                /*

+                  Audit is broken in containers, much of the userspace audit hookup will fail if running inside a

+                  container. We don't care and just turn off creation of audit sockets.

+

+                  This will make socket(AF_NETLINK, *, NETLINK_AUDIT) fail with EAFNOSUPPORT which audit userspace uses

+                  as indication that audit is disabled in the kernel.

+                */

+

+                r = seccomp_rule_add_exact(

+                                seccomp,

+                                SCMP_ACT_ERRNO(EAFNOSUPPORT),

+                                SCMP_SYS(socket),

+                                2,

+                                SCMP_A0(SCMP_CMP_EQ, AF_NETLINK),

+                                SCMP_A2(SCMP_CMP_EQ, NETLINK_AUDIT));

+                if (r < 0)

+                        log_debug_errno(r, "Failed to add audit seccomp rule, ignoring: %m");

+                else

+                        n++;

+

+                if (n <= 0) /* no rule added? then skip this architecture */

+                        continue;

-        r = seccomp_load(seccomp);

-        if (r < 0) {

-                log_error_errno(r, "Failed to install seccomp audit filter: %m");

-                goto finish;

+                r = seccomp_load(seccomp);

+                if (IN_SET(r, -EPERM, -EACCES))

+                        return log_error_errno(r, "Failed to install seccomp audit filter: %m");

+                if (r < 0)

+                        log_debug_errno(r, "Failed to install filter set for architecture %s, skipping: %m", seccomp_arch_to_string(arch));

         }

-finish:

-        seccomp_release(seccomp);

-        return r;

+        return 0;

 }

 #else

diff --git a/src/shared/seccomp-util.c b/src/shared/seccomp-util.c

index 55b97e1efb..aa37e12db7 100644

--- a/src/shared/seccomp-util.c

+++ b/src/shared/seccomp-util.c

@@ -18,17 +18,52 @@

 ***/

 #include <errno.h>

+#include <linux/seccomp.h>

 #include <seccomp.h>

 #include <stddef.h>

+#include <sys/mman.h>

 #include <sys/prctl.h>

-#include <linux/seccomp.h>

+#include <sys/shm.h>

+#include "af-list.h"

 #include "alloc-util.h"

 #include "macro.h"

 #include "nsflags.h"

 #include "seccomp-util.h"

 #include "string-util.h"

 #include "util.h"

+#include "errno-list.h"

+

+const uint32_t seccomp_local_archs[] = {

+

+#if defined(__i386__) || defined(__x86_64__)

+                SCMP_ARCH_X86,

+                SCMP_ARCH_X86_64,

+                SCMP_ARCH_X32,

+

+#elif defined(__arm__) || defined(__aarch64__)