Merge pull request #3685 from kinvolk/alessandro/inaccessible-paths

namespace: unify limit behavior on non-directory paths

10 files changed, 107 insertions, 57 deletions

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 90b7a885a8..63dff3dd5c 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -532,3 +532,21 @@ int repeat_unmount(const char *path, int flags) {
                 done = true;
         }
 }
+
+const char* mode_to_inaccessible_node(mode_t mode) {
+        switch(mode & S_IFMT) {
+                case S_IFREG:
+                        return "/run/systemd/inaccessible/reg";
+                case S_IFDIR:
+                        return "/run/systemd/inaccessible/dir";
+                case S_IFCHR:
+                        return "/run/systemd/inaccessible/chr";
+                case S_IFBLK:
+                        return "/run/systemd/inaccessible/blk";
+                case S_IFIFO:
+                        return "/run/systemd/inaccessible/fifo";
+                case S_IFSOCK:
+                        return "/run/systemd/inaccessible/sock";
+        }
+        return NULL;
+}
diff --git a/src/basic/mount-util.h b/src/basic/mount-util.h
index bdb525d6b0..f46989ebb3 100644
--- a/src/basic/mount-util.h
+++ b/src/basic/mount-util.h
@@ -49,4 +49,6 @@ union file_handle_union {
         char padding[sizeof(struct file_handle) + MAX_HANDLE_SZ];
 };
 
+const char* mode_to_inaccessible_node(mode_t mode);
+
 #define FILE_HANDLE_INIT { .handle.handle_bytes = MAX_HANDLE_SZ }
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index 644b9561b5..b2ef3db491 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -695,9 +695,12 @@ const sd_bus_vtable bus_exec_vtable[] = {
         SD_BUS_PROPERTY("Group", "s", NULL, offsetof(ExecContext, group), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("SupplementaryGroups", "as", NULL, offsetof(ExecContext, supplementary_groups), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("PAMName", "s", NULL, offsetof(ExecContext, pam_name), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("ReadWriteDirectories", "as", NULL, offsetof(ExecContext, read_write_dirs), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("ReadOnlyDirectories", "as", NULL, offsetof(ExecContext, read_only_dirs), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("InaccessibleDirectories", "as", NULL, offsetof(ExecContext, inaccessible_dirs), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("ReadWriteDirectories", "as", NULL, offsetof(ExecContext, read_write_paths), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("ReadOnlyDirectories", "as", NULL, offsetof(ExecContext, read_only_paths), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("InaccessibleDirectories", "as", NULL, offsetof(ExecContext, inaccessible_paths), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("ReadWritePaths", "as", NULL, offsetof(ExecContext, read_write_paths), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("ReadOnlyPaths", "as", NULL, offsetof(ExecContext, read_only_paths), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("InaccessiblePaths", "as", NULL, offsetof(ExecContext, inaccessible_paths), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("MountFlags", "t", bus_property_get_ulong, offsetof(ExecContext, mount_flags), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("PrivateTmp", "b", bus_property_get_bool, offsetof(ExecContext, private_tmp), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("PrivateNetwork", "b", bus_property_get_bool, offsetof(ExecContext, private_network), SD_BUS_VTABLE_PROPERTY_CONST),
@@ -1323,8 +1326,8 @@ int bus_exec_context_set_transient_property(
 
                 return 1;
 
-        } else if (STR_IN_SET(name, "ReadWriteDirectories", "ReadOnlyDirectories", "InaccessibleDirectories")) {
-
+        } else if (STR_IN_SET(name, "ReadWriteDirectories", "ReadOnlyDirectories", "InaccessibleDirectories",
+                              "ReadWritePaths", "ReadOnlyPaths", "InaccessiblePaths")) {
                 _cleanup_strv_free_ char **l = NULL;
                 char ***dirs;
                 char **p;
@@ -1346,12 +1349,12 @@ int bus_exec_context_set_transient_property(
                 if (mode != UNIT_CHECK) {
                         _cleanup_free_ char *joined = NULL;
 
-                        if (streq(name, "ReadWriteDirectories"))
-                                dirs = &c->read_write_dirs;
-                        else if (streq(name, "ReadOnlyDirectories"))
-                                dirs = &c->read_only_dirs;
-                        else /* "InaccessibleDirectories" */
-                                dirs = &c->inaccessible_dirs;
+                        if (STR_IN_SET(name, "ReadWriteDirectories", "ReadWritePaths"))
+                                dirs = &c->read_write_paths;
+                        else if (STR_IN_SET(name, "ReadOnlyDirectories", "ReadOnlyPaths"))
+                                dirs = &c->read_only_paths;
+                        else /* "InaccessiblePaths" */
+                                dirs = &c->inaccessible_paths;
 
                         if (strv_length(l) == 0) {
                                 *dirs = strv_free(*dirs);
diff --git a/src/core/execute.c b/src/core/execute.c
index f4f5723c35..05dc1aaec1 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1507,9 +1507,9 @@ static bool exec_needs_mount_namespace(
         assert(context);
         assert(params);
 
-        if (!strv_isempty(context->read_write_dirs) ||
-            !strv_isempty(context->read_only_dirs) ||
-            !strv_isempty(context->inaccessible_dirs))
+        if (!strv_isempty(context->read_write_paths) ||
+            !strv_isempty(context->read_only_paths) ||
+            !strv_isempty(context->inaccessible_paths))
                 return true;
 
         if (context->mount_flags != 0)
@@ -1933,9 +1933,9 @@ static int exec_child(
 
                 r = setup_namespace(
                                 params->apply_chroot ? context->root_directory : NULL,
-                                context->read_write_dirs,
-                                context->read_only_dirs,
-                                context->inaccessible_dirs,
+                                context->read_write_paths,
+                                context->read_only_paths,
+                                context->inaccessible_paths,
                                 tmp,
                                 var,
                                 context->private_devices,
@@ -2324,9 +2324,9 @@ void exec_context_done(ExecContext *c) {
 
         c->pam_name = mfree(c->pam_name);
 
-        c->read_only_dirs = strv_free(c->read_only_dirs);
-        c->read_write_dirs = strv_free(c->read_write_dirs);
-        c->inaccessible_dirs = strv_free(c->inaccessible_dirs);
+        c->read_only_paths = strv_free(c->read_only_paths);
+        c->read_write_paths = strv_free(c->read_write_paths);
+        c->inaccessible_paths = strv_free(c->inaccessible_paths);
 
         if (c->cpuset)
                 CPU_FREE(c->cpuset);
@@ -2732,21 +2732,21 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
         if (c->pam_name)
                 fprintf(f, "%sPAMName: %s\n", prefix, c->pam_name);
 
-        if (strv_length(c->read_write_dirs) > 0) {
-                fprintf(f, "%sReadWriteDirs:", prefix);
-                strv_fprintf(f, c->read_write_dirs);
+        if (strv_length(c->read_write_paths) > 0) {
+                fprintf(f, "%sReadWritePaths:", prefix);
+                strv_fprintf(f, c->read_write_paths);
                 fputs("\n", f);
         }
 
-        if (strv_length(c->read_only_dirs) > 0) {
-                fprintf(f, "%sReadOnlyDirs:", prefix);
-                strv_fprintf(f, c->read_only_dirs);
+        if (strv_length(c->read_only_paths) > 0) {
+                fprintf(f, "%sReadOnlyPaths:", prefix);
+                strv_fprintf(f, c->read_only_paths);
                 fputs("\n", f);
         }
 
-        if (strv_length(c->inaccessible_dirs) > 0) {
-                fprintf(f, "%sInaccessibleDirs:", prefix);
-                strv_fprintf(f, c->inaccessible_dirs);
+        if (strv_length(c->inaccessible_paths) > 0) {
+                fprintf(f, "%sInaccessiblePaths:", prefix);
+                strv_fprintf(f, c->inaccessible_paths);
                 fputs("\n", f);
         }
 
diff --git a/src/core/execute.h b/src/core/execute.h
index cacf66cf51..73b8a119b0 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -152,7 +152,7 @@ struct ExecContext {
         bool smack_process_label_ignore;
         char *smack_process_label;
 
-        char **read_write_dirs, **read_only_dirs, **inaccessible_dirs;
+        char **read_write_paths, **read_only_paths, **inaccessible_paths;
         unsigned long mount_flags;
 
         uint64_t capability_bounding_set;
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index fe1006830b..6a5c16a000 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -80,9 +80,12 @@ $1.LimitMSGQUEUE,                config_parse_limit,                 RLIMIT_MSGQ
 $1.LimitNICE,                    config_parse_limit,                 RLIMIT_NICE,                   offsetof($1, exec_context.rlimit)
 $1.LimitRTPRIO,                  config_parse_limit,                 RLIMIT_RTPRIO,                 offsetof($1, exec_context.rlimit)
 $1.LimitRTTIME,                  config_parse_limit,                 RLIMIT_RTTIME,                 offsetof($1, exec_context.rlimit)
-$1.ReadWriteDirectories,         config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_write_dirs)
-$1.ReadOnlyDirectories,          config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_only_dirs)
-$1.InaccessibleDirectories,      config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.inaccessible_dirs)
+$1.ReadWriteDirectories,         config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_write_paths)
+$1.ReadOnlyDirectories,          config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_only_paths)
+$1.InaccessibleDirectories,      config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.inaccessible_paths)
+$1.ReadWritePaths,               config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_write_paths)
+$1.ReadOnlyPaths,                config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_only_paths)
+$1.InaccessiblePaths,            config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.inaccessible_paths)
 $1.PrivateTmp,                   config_parse_bool,                  0,                             offsetof($1, exec_context.private_tmp)
 $1.PrivateNetwork,               config_parse_bool,                  0,                             offsetof($1, exec_context.private_network)
 $1.PrivateDevices,               config_parse_bool,                  0,                             offsetof($1, exec_context.private_devices)
diff --git a/src/core/mount-setup.c b/src/core/mount-setup.c
index f9c9b4a91f..5d8ab0ec70 100644
--- a/src/core/mount-setup.c
+++ b/src/core/mount-setup.c
@@ -28,6 +28,7 @@
 #include "cgroup-util.h"
 #include "dev-setup.h"
 #include "efivars.h"
+#include "fs-util.h"
 #include "label.h"
 #include "log.h"
 #include "macro.h"
@@ -403,9 +404,16 @@ int mount_setup(bool loaded_policy) {
          * really needs to stay for good, otherwise software that
          * copied sd-daemon.c into their sources will misdetect
          * systemd. */
-        mkdir_label("/run/systemd", 0755);
-        mkdir_label("/run/systemd/system", 0755);
-        mkdir_label("/run/systemd/inaccessible", 0000);
+        (void) mkdir_label("/run/systemd", 0755);
+        (void) mkdir_label("/run/systemd/system", 0755);
+        (void) mkdir_label("/run/systemd/inaccessible", 0000);
+        /* Set up inaccessible items */
+        (void) mknod("/run/systemd/inaccessible/reg", S_IFREG | 0000, 0);
+        (void) mkdir_label("/run/systemd/inaccessible/dir", 0000);
+        (void) mknod("/run/systemd/inaccessible/chr", S_IFCHR | 0000, makedev(0, 0));
+        (void) mknod("/run/systemd/inaccessible/blk", S_IFBLK | 0000, makedev(0, 0));
+        (void) mkfifo("/run/systemd/inaccessible/fifo", 0000);
+        (void) mknod("/run/systemd/inaccessible/sock", S_IFSOCK | 0000, 0);
 
         return 0;
 }
diff --git a/src/core/namespace.c b/src/core/namespace.c
index 203d122810..722538caf1 100644
--- a/src/core/namespace.c
+++ b/src/core/namespace.c
@@ -278,6 +278,7 @@ static int apply_mount(
 
         const char *what;
         int r;
+        struct stat target;
 
         assert(m);
 
@@ -287,12 +288,22 @@ static int apply_mount(
 
                 /* First, get rid of everything that is below if there
                  * is anything... Then, overmount it with an
-                 * inaccessible directory. */
+                 * inaccessible path. */
                 umount_recursive(m->path, 0);
 
-                what = "/run/systemd/inaccessible";
-                break;
+                r = lstat(m->path, &target);
+                if (r != 0) {
+                        if (m->ignore && errno == ENOENT)
+                                return 0;
+                        return -errno;
+                }
 
+                what = mode_to_inaccessible_node(target.st_mode);
+                if (what == NULL) {
+                        log_debug("File type not supported. Note that symlinks are not allowed");
+                        return -ELOOP;
+                }
+                break;
         case READONLY:
         case READWRITE:
                 /* Nothing to mount here, we just later toggle the
@@ -317,12 +328,16 @@ static int apply_mount(
         assert(what);
 
         r = mount(what, m->path, NULL, MS_BIND|MS_REC, NULL);
-        if (r >= 0)
+        if (r >= 0) {
                 log_debug("Successfully mounted %s to %s", what, m->path);
-        else if (m->ignore && errno == ENOENT)
-                return 0;
-
-        return r;
+                return r;
+        }
+        else {
+                if (m->ignore && errno == ENOENT)
+                        return 0;
+                log_debug("Failed mounting %s to %s: %s", what, m->path, strerror(errno));
+                return -errno;
+        }
 }
 
 static int make_read_only(BindMount *m) {
@@ -347,9 +362,9 @@ static int make_read_only(BindMount *m) {
 
 int setup_namespace(
                 const char* root_directory,
-                char** read_write_dirs,
-                char** read_only_dirs,
-                char** inaccessible_dirs,
+                char** read_write_paths,
+                char** read_only_paths,
+                char** inaccessible_paths,
                 const char* tmp_dir,
                 const char* var_tmp_dir,
                 bool private_dev,
@@ -368,9 +383,9 @@ int setup_namespace(
                 return -errno;
 
         n = !!tmp_dir + !!var_tmp_dir +
-                strv_length(read_write_dirs) +
-                strv_length(read_only_dirs) +
-                strv_length(inaccessible_dirs) +
+                strv_length(read_write_paths) +
+                strv_length(read_only_paths) +
+                strv_length(inaccessible_paths) +
                 private_dev +
                 (protect_home != PROTECT_HOME_NO ? 3 : 0) +
                 (protect_system != PROTECT_SYSTEM_NO ? 2 : 0) +
@@ -378,15 +393,15 @@ int setup_namespace(
 
         if (n > 0) {
                 m = mounts = (BindMount *) alloca0(n * sizeof(BindMount));
-                r = append_mounts(&m, read_write_dirs, READWRITE);
+                r = append_mounts(&m, read_write_paths, READWRITE);
                 if (r < 0)
                         return r;
 
-                r = append_mounts(&m, read_only_dirs, READONLY);
+                r = append_mounts(&m, read_only_paths, READONLY);
                 if (r < 0)
                         return r;
 
-                r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE);
+                r = append_mounts(&m, inaccessible_paths, INACCESSIBLE);
                 if (r < 0)
                         return r;
 
diff --git a/src/core/namespace.h b/src/core/namespace.h
index b54b7b47d6..1aedf5f208 100644
--- a/src/core/namespace.h
+++ b/src/core/namespace.h
@@ -40,9 +40,9 @@ typedef enum ProtectSystem {
 } ProtectSystem;
 
 int setup_namespace(const char *chroot,
-                    char **read_write_dirs,
-                    char **read_only_dirs,
-                    char **inaccessible_dirs,
+                    char **read_write_paths,
+                    char **read_only_paths,
+                    char **inaccessible_paths,
                     const char *tmp_dir,
                     const char *var_tmp_dir,
                     bool private_dev,
diff --git a/src/shared/bus-unit-util.c b/src/shared/bus-unit-util.c
index 04471e2373..94ffa8af87 100644
--- a/src/shared/bus-unit-util.c
+++ b/src/shared/bus-unit-util.c
@@ -453,7 +453,8 @@ int bus_append_unit_property_assignment(sd_bus_message *m, const char *assignmen
                 }
 
                 r = sd_bus_message_append(m, "v", "i", oa);
-        } else if (STR_IN_SET(field, "ReadWriteDirectories", "ReadOnlyDirectories", "InaccessibleDirectories")) {
+        } else if (STR_IN_SET(field, "ReadWriteDirectories", "ReadOnlyDirectories", "InaccessibleDirectories",
+                              "ReadWritePaths", "ReadOnlyPaths", "InaccessiblePaths")) {
                 const char *p;
 
                 r = sd_bus_message_open_container(m, 'v', "as");