chiark / gitweb /
nspawn: reset supplementary and main group id before entering nspawn
[elogind.git] / src / nspawn / nspawn.c
index b494045b8853212a188f9d5ba25ca25aa93ccd75..59171abff3cdb6c2e14ffbf50d9fb372baed362e 100644 (file)
@@ -284,9 +284,9 @@ static int mount_all(const char *dest) {
 
         unsigned k;
         int r = 0;
-        char _cleanup_free_ *where = NULL;
 
         for (k = 0; k < ELEMENTSOF(mount_table); k++) {
+                char _cleanup_free_ *where = NULL;
                 int t;
 
                 if (asprintf(&where, "%s/%s", dest, mount_table[k].where) < 0) {
@@ -332,28 +332,61 @@ static int mount_all(const char *dest) {
 }
 
 static int setup_timezone(const char *dest) {
-        char *where;
+        _cleanup_free_ char *where = NULL, *p = NULL, *q = NULL, *check = NULL, *what = NULL;
+        char *z, *y;
+        int r;
 
         assert(dest);
 
         /* Fix the timezone, if possible */
+        r = readlink_malloc("/etc/localtime", &p);
+        if (r < 0) {
+                log_warning("/etc/localtime is not a symlink, not updating container timezone.");
+                return 0;
+        }
+
+        z = path_startswith(p, "../usr/share/zoneinfo/");
+        if (!z)
+                z = path_startswith(p, "/usr/share/zoneinfo/");
+        if (!z) {
+                log_warning("/etc/localtime does not point into /usr/share/zoneinfo/, not updating container timezone.");
+                return 0;
+        }
+
         where = strappend(dest, "/etc/localtime");
         if (!where)
                 return log_oom();
 
-        if (mount("/etc/localtime", where, "bind", MS_BIND, NULL) >= 0)
-                mount("/etc/localtime", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
+        r = readlink_malloc(where, &q);
+        if (r >= 0) {
+                y = path_startswith(q, "../usr/share/zoneinfo/");
+                if (!y)
+                        y = path_startswith(q, "/usr/share/zoneinfo/");
 
-        free(where);
 
-        where = strappend(dest, "/etc/timezone");
-        if (!where)
+                /* Already pointing to the right place? Then do nothing .. */
+                if (y && streq(y, z))
+                        return 0;
+        }
+
+        check = strjoin(dest, "/usr/share/zoneinfo/", z, NULL);
+        if (!check)
                 return log_oom();
 
-        if (mount("/etc/timezone", where, "bind", MS_BIND, NULL) >= 0)
-                mount("/etc/timezone", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
+        if (access(check, F_OK) < 0) {
+                log_warning("Timezone %s does not exist in container, not updating container timezone.", z);
+                return 0;
+        }
 
-        free(where);
+        what = strappend("../usr/share/zoneinfo/", z);
+        if (!what)
+                return log_oom();
+
+        unlink(where);
+        if (symlink(what, where) < 0) {
+                log_error("Failed to correct timezone of container: %m");
+                return 0;
+        }
 
         return 0;
 }
@@ -371,6 +404,8 @@ static int setup_resolv_conf(const char *dest) {
         if (!where)
                 return log_oom();
 
+        /* We don't really care for the results of this really. If it
+         * fails, it fails, but meh... */
         if (mount("/etc/resolv.conf", where, "bind", MS_BIND, NULL) >= 0)
                 mount("/etc/resolv.conf", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
 
@@ -633,58 +668,58 @@ static int setup_hostname(void) {
 
 static int setup_journal(const char *directory) {
         sd_id128_t machine_id;
-        char *p = NULL, *b = NULL, *l, *q = NULL, *d = NULL;
+        char _cleanup_free_ *p = NULL, *b = NULL, *q = NULL, *d = NULL;
+        char *id;
         int r;
 
         if (arg_link_journal == LINK_NO)
                 return 0;
 
         p = strappend(directory, "/etc/machine-id");
-        if (!p) {
-                r = log_oom();
-                goto finish;
-        }
+        if (!p)
+                return log_oom();
 
         r = read_one_line_file(p, &b);
-        if (r == -ENOENT && arg_link_journal == LINK_AUTO) {
-                r = 0;
-                goto finish;
-        } else if (r < 0) {
-                log_error("Failed to read machine ID: %s", strerror(-r));
+        if (r == -ENOENT && arg_link_journal == LINK_AUTO)
+                return 0;
+        else if (r < 0) {
+                log_error("Failed to read machine ID from %s: %s", p, strerror(-r));
                 return r;
         }
 
-        l = strstrip(b);
-        if (isempty(l) && arg_link_journal == LINK_AUTO) {
-                r = 0;
-                goto finish;
-        }
+        id = strstrip(b);
+        if (isempty(id) && arg_link_journal == LINK_AUTO)
+                return 0;
 
-        /* Verify validaty */
-        r = sd_id128_from_string(l, &machine_id);
+        /* Verify validity */
+        r = sd_id128_from_string(id, &machine_id);
         if (r < 0) {
-                log_error("Failed to parse machine ID: %s", strerror(-r));
-                goto finish;
+                log_error("Failed to parse machine ID from %s: %s", p, strerror(-r));
+                return r;
         }
 
         free(p);
-        p = strappend("/var/log/journal/", l);
-        q = strjoin(directory, "/var/log/journal/", l, NULL);
-        if (!p || !q) {
-                r = log_oom();
-                goto finish;
+        p = strappend("/var/log/journal/", id);
+        q = strjoin(directory, "/var/log/journal/", id, NULL);
+        if (!p || !q)
+                return log_oom();
+
+        if (path_is_mount_point(p, false) > 0) {
+                if (arg_link_journal != LINK_AUTO) {
+                        log_error("%s: already a mount point, refusing to use for journal", p);
+                        return -EEXIST;
+                }
+
+                return 0;
         }
 
-        if (path_is_mount_point(p, false) > 0 ||
-            path_is_mount_point(q, false) > 0) {
+        if (path_is_mount_point(q, false) > 0) {
                 if (arg_link_journal != LINK_AUTO) {
-                        log_error("Journal already a mount point, refusing.");
-                        r = -EEXIST;
-                        goto finish;
+                        log_error("%s: already a mount point, refusing to use for journal", q);
+                        return -EEXIST;
                 }
 
-                r = 0;
-                goto finish;
+                return 0;
         }
 
         r = readlink_and_make_absolute(p, &d);
@@ -693,89 +728,74 @@ static int setup_journal(const char *directory) {
                      arg_link_journal == LINK_AUTO) &&
                     path_equal(d, q)) {
 
-                        mkdir_p(q, 0755);
-
-                        r = 0;
-                        goto finish;
+                        r = mkdir_p(q, 0755);
+                        if (r < 0)
+                                log_warning("failed to create directory %s: %m", q);
+                        return 0;
                 }
 
                 if (unlink(p) < 0) {
                         log_error("Failed to remove symlink %s: %m", p);
-                        r = -errno;
-                        goto finish;
+                        return -errno;
                 }
         } else if (r == -EINVAL) {
 
                 if (arg_link_journal == LINK_GUEST &&
                     rmdir(p) < 0) {
 
-                        if (errno == ENOTDIR)
-                                log_error("%s already exists and is neither symlink nor directory.", p);
-                        else {
+                        if (errno == ENOTDIR) {
+                                log_error("%s already exists and is neither a symlink nor a directory", p);
+                                return r;
+                        } else {
                                 log_error("Failed to remove %s: %m", p);
-                                r = -errno;
+                                return -errno;
                         }
-
-                        goto finish;
                 }
         } else if (r != -ENOENT) {
                 log_error("readlink(%s) failed: %m", p);
-                goto finish;
+                return r;
         }
 
         if (arg_link_journal == LINK_GUEST) {
 
                 if (symlink(q, p) < 0) {
                         log_error("Failed to symlink %s to %s: %m", q, p);
-                        r = -errno;
-                        goto finish;
+                        return -errno;
                 }
 
-                mkdir_p(q, 0755);
-
-                r = 0;
-                goto finish;
+                r = mkdir_p(q, 0755);
+                if (r < 0)
+                        log_warning("failed to create directory %s: %m", q);
+                return 0;
         }
 
         if (arg_link_journal == LINK_HOST) {
                 r = mkdir_p(p, 0755);
                 if (r < 0) {
                         log_error("Failed to create %s: %m", p);
-                        goto finish;
+                        return r;
                 }
 
-        } else if (access(p, F_OK) < 0) {
-                r = 0;
-                goto finish;
-        }
+        } else if (access(p, F_OK) < 0)
+                return 0;
 
         if (dir_is_empty(q) == 0) {
                 log_error("%s not empty.", q);
-                r = -ENOTEMPTY;
-                goto finish;
+                return -ENOTEMPTY;
         }
 
         r = mkdir_p(q, 0755);
         if (r < 0) {
                 log_error("Failed to create %s: %m", q);
-                goto finish;
+                return r;
         }
 
         if (mount(p, q, "bind", MS_BIND, NULL) < 0) {
                 log_error("Failed to bind mount journal from host into guest: %m");
-                r = -errno;
-                goto finish;
+                return -errno;
         }
 
-        r = 0;
-
-finish:
-        free(p);
-        free(q);
-        free(d);
-        free(b);
-        return r;
-
+        return 0;
 }
 
 static int drop_capabilities(void) {
@@ -1272,6 +1292,12 @@ int main(int argc, char *argv[]) {
 
                         if (arg_user) {
 
+                                /* Note that this resolves user names
+                                 * inside the container, and hence
+                                 * accesses the NSS modules from the
+                                 * container and not the host. This is
+                                 * a bit weird... */
+
                                 if (get_user_creds((const char**)&arg_user, &uid, &gid, &home, NULL) < 0) {
                                         log_error("get_user_creds() failed: %m");
                                         goto child_fail;
@@ -1301,6 +1327,23 @@ int main(int argc, char *argv[]) {
                                         log_error("setreuid() failed: %m");
                                         goto child_fail;
                                 }
+                        } else {
+                                /* Reset everything fully to 0, just in case */
+
+                                if (setgroups(0, NULL) < 0) {
+                                        log_error("setgroups() failed: %m");
+                                        goto child_fail;
+                                }
+
+                                if (setresgid(0, 0, 0) < 0) {
+                                        log_error("setregid() failed: %m");
+                                        goto child_fail;
+                                }
+
+                                if (setresuid(0, 0, 0) < 0) {
+                                        log_error("setreuid() failed: %m");
+                                        goto child_fail;
+                                }
                         }
 
                         if ((asprintf((char**)(envp + 3), "HOME=%s", home ? home: "/root") < 0) ||