chiark / gitweb /
cryptsetup: warn if /etc/crypttab is world-readable
[elogind.git] / src / cryptsetup / cryptsetup-generator.c
index 6e7b7070e22586f8b6b10c00ea86045c123e33c6..7eae1c8c6721f07353a9603fab575c98c37a8ad0 100644 (file)
 #include "mkdir.h"
 #include "virt.h"
 #include "strv.h"
+#include "fileio.h"
 
 static const char *arg_dest = "/tmp";
 static bool arg_enabled = true;
 static bool arg_read_crypttab = true;
-static char **arg_proc_cmdline_disks = NULL;
 
 static bool has_option(const char *haystack, const char *needle) {
         const char *f = haystack;
@@ -70,9 +70,8 @@ static int create_disk(
                 const char *password,
                 const char *options) {
 
-        char *p = NULL, *n = NULL, *d = NULL, *u = NULL, *from = NULL, *to = NULL, *e = NULL;
-        int r;
-        FILE *f = NULL;
+        _cleanup_free_ char *p = NULL, *n = NULL, *d = NULL, *u = NULL, *from = NULL, *to = NULL, *e = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
         bool noauto, nofail;
 
         assert(name);
@@ -82,59 +81,65 @@ static int create_disk(
         nofail = has_option(options, "nofail");
 
         n = unit_name_from_path_instance("systemd-cryptsetup", name, ".service");
-        if (!n) {
-                r = log_oom();
-                goto fail;
-        }
+        if (!n)
+                return log_oom();
 
         p = strjoin(arg_dest, "/", n, NULL);
-        if (!p) {
-                r = log_oom();
-                goto fail;
-        }
+        if (!p)
+                return log_oom();
 
         u = fstab_node_to_udev_node(device);
-        if (!u) {
-                r = log_oom();
-                goto fail;
-        }
+        if (!u)
+                return log_oom();
 
         d = unit_name_from_path(u, ".device");
-        if (!d) {
-                r = log_oom();
-                goto fail;
-        }
+        if (!d)
+                return log_oom();
 
         f = fopen(p, "wxe");
         if (!f) {
-                r = -errno;
                 log_error("Failed to create unit file %s: %m", p);
-                goto fail;
+                return -errno;
         }
 
-        fprintf(f,
+        fputs(
                 "# Automatically generated by systemd-cryptsetup-generator\n\n"
                 "[Unit]\n"
-                "Description=Cryptography Setup for %%I\n"
+                "Description=Cryptography Setup for %I\n"
                 "Documentation=man:systemd-cryptsetup@.service(8) man:crypttab(5)\n"
                 "SourcePath=/etc/crypttab\n"
                 "Conflicts=umount.target\n"
                 "DefaultDependencies=no\n"
-                "BindsTo=%s dev-mapper-%%i.device\n"
-                "After=systemd-readahead-collect.service systemd-readahead-replay.service %s\n"
-                "Before=umount.target\n",
-                d, d);
+                "BindsTo=dev-mapper-%i.device\n"
+                "After=systemd-readahead-collect.service systemd-readahead-replay.service\n",
+                f);
 
         if (!nofail)
                 fprintf(f,
                         "Before=cryptsetup.target\n");
 
-        if (password && (streq(password, "/dev/urandom") ||
-                         streq(password, "/dev/random") ||
-                         streq(password, "/dev/hw_random")))
-                fputs("After=systemd-random-seed-load.service\n", f);
+        if (password) {
+                if (streq(password, "/dev/urandom") ||
+                    streq(password, "/dev/random") ||
+                    streq(password, "/dev/hw_random"))
+                        fputs("After=systemd-random-seed-load.service\n", f);
+                else if (!streq(password, "-") &&
+                         !streq(password, "none"))
+                        fprintf(f,
+                                "RequiresMountsFor=%s\n",
+                                password);
+        }
+
+        if (is_device_path(u))
+                fprintf(f,
+                        "BindsTo=%s\n"
+                        "After=%s\n"
+                        "Before=umount.target\n",
+                        d, d);
         else
-                fputs("Before=local-fs.target\n", f);
+                fprintf(f,
+                        "RequiresMountsFor=%s\n",
+                        u);
 
         fprintf(f,
                 "\n[Service]\n"
@@ -159,86 +164,78 @@ static int create_disk(
         fflush(f);
 
         if (ferror(f)) {
-                r = -errno;
                 log_error("Failed to write file %s: %m", p);
-                goto fail;
+                return -errno;
         }
 
-        if (asprintf(&from, "../%s", n) < 0) {
-                r = log_oom();
-                goto fail;
-        }
+        if (asprintf(&from, "../%s", n) < 0)
+                return log_oom();
 
         if (!noauto) {
 
                 to = strjoin(arg_dest, "/", d, ".wants/", n, NULL);
-                if (!to) {
-                        r = log_oom();
-                        goto fail;
-                }
+                if (!to)
+                        return log_oom();
 
                 mkdir_parents_label(to, 0755);
                 if (symlink(from, to) < 0) {
-                        log_error("Failed to create symlink '%s' to '%s': %m", from, to);
-                        r = -errno;
-                        goto fail;
+                        log_error("Failed to create symlink %s: %m", to);
+                        return -errno;
                 }
 
                 free(to);
-
                 if (!nofail)
                         to = strjoin(arg_dest, "/cryptsetup.target.requires/", n, NULL);
                 else
                         to = strjoin(arg_dest, "/cryptsetup.target.wants/", n, NULL);
-                if (!to) {
-                        r = log_oom();
-                        goto fail;
-                }
+                if (!to)
+                        return log_oom();
 
                 mkdir_parents_label(to, 0755);
                 if (symlink(from, to) < 0) {
-                        log_error("Failed to create symlink '%s' to '%s': %m", from, to);
-                        r = -errno;
-                        goto fail;
+                        log_error("Failed to create symlink %s: %m", to);
+                        return -errno;
                 }
-
-                free(to);
-                to = NULL;
         }
 
         e = unit_name_escape(name);
+        if (!e)
+                return log_oom();
+
+        free(to);
         to = strjoin(arg_dest, "/dev-mapper-", e, ".device.requires/", n, NULL);
-        if (!to) {
-                r = log_oom();
-                goto fail;
-        }
+        if (!to)
+                return log_oom();
 
         mkdir_parents_label(to, 0755);
         if (symlink(from, to) < 0) {
-                log_error("Failed to create symlink '%s' to '%s': %m", from, to);
-                r = -errno;
-                goto fail;
+                log_error("Failed to create symlink %s: %m", to);
+                return -errno;
         }
 
-        r = 0;
-
-fail:
-        free(p);
-        free(n);
-        free(d);
-        free(e);
-
-        free(from);
-        free(to);
-
-        if (f)
-                fclose(f);
+        if (!noauto && !nofail) {
+                int r;
+                free(p);
+                p = strjoin(arg_dest, "/dev-mapper-", e, ".device.d/50-job-timeout-sec-0.conf", NULL);
+                if (!p)
+                        return log_oom();
+
+                mkdir_parents_label(p, 0755);
+
+                r = write_string_file(p,
+                                "# Automatically generated by systemd-cryptsetup-generator\n\n"
+                                "[Unit]\n"
+                                "JobTimeoutSec=0\n"); /* the binary handles timeouts anyway */
+                if (r)
+                        return r;
+        }
 
-        return r;
+        return 0;
 }
 
-static int parse_proc_cmdline(void) {
-        char *line, *w, *state;
+static int parse_proc_cmdline(char ***arg_proc_cmdline_disks, char **arg_proc_cmdline_keyfile) {
+        _cleanup_free_ char *line = NULL;
+        char *w = NULL, *state = NULL;
         int r;
         size_t l;
 
@@ -252,13 +249,11 @@ static int parse_proc_cmdline(void) {
         }
 
         FOREACH_WORD_QUOTED(w, l, line, state) {
-                char *word;
+                _cleanup_free_ char *word = NULL;
 
                 word = strndup(w, l);
-                if (!word) {
-                        r = log_oom();
-                        goto finish;
-                }
+                if (!word)
+                        return log_oom();
 
                 if (startswith(word, "luks=")) {
                         r = parse_boolean(word + 5);
@@ -295,28 +290,29 @@ static int parse_proc_cmdline(void) {
                         }
 
                 } else if (startswith(word, "luks.uuid=")) {
-                        char **t;
-
-                        t = strv_append(arg_proc_cmdline_disks, word + 10);
-                        if (!t) {
-                                r = log_oom();
-                                goto finish;
-                        }
-                        strv_free(arg_proc_cmdline_disks);
-                        arg_proc_cmdline_disks = t;
+                        if (strv_extend(arg_proc_cmdline_disks, word + 10) < 0)
+                                return log_oom();
 
                 } else if (startswith(word, "rd.luks.uuid=")) {
 
                         if (in_initrd()) {
-                                char **t;
+                                if (strv_extend(arg_proc_cmdline_disks, word + 13) < 0)
+                                        return log_oom();
+                        }
 
-                                t = strv_append(arg_proc_cmdline_disks, word + 13);
-                                if (!t) {
-                                        r = log_oom();
-                                        goto finish;
-                                }
-                                strv_free(arg_proc_cmdline_disks);
-                                arg_proc_cmdline_disks = t;
+                } else if (startswith(word, "luks.key=")) {
+                        *arg_proc_cmdline_keyfile = strdup(word + 9);
+                        if (!*arg_proc_cmdline_keyfile)
+                                return log_oom();
+
+                } else if (startswith(word, "rd.luks.key=")) {
+
+                        if (in_initrd()) {
+                                if (*arg_proc_cmdline_keyfile)
+                                        free(*arg_proc_cmdline_keyfile);
+                                *arg_proc_cmdline_keyfile = strdup(word + 12);
+                                if (!*arg_proc_cmdline_keyfile)
+                                        return log_oom();
                         }
 
                 } else if (startswith(word, "luks.") ||
@@ -324,21 +320,20 @@ static int parse_proc_cmdline(void) {
 
                         log_warning("Unknown kernel switch %s. Ignoring.", word);
                 }
-
-                free(word);
         }
 
-        r = 0;
+        strv_uniq(*arg_proc_cmdline_disks);
 
-finish:
-        free(line);
-        return r;
+        return 0;
 }
 
 int main(int argc, char *argv[]) {
-        FILE *f = NULL;
-        int r = EXIT_SUCCESS;
+        _cleanup_strv_free_ char **arg_proc_cmdline_disks_done = NULL;
+        _cleanup_strv_free_ char **arg_proc_cmdline_disks = NULL;
+        _cleanup_free_ char *arg_proc_cmdline_keyfile = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
         unsigned n = 0;
+        int r = EXIT_SUCCESS;
         char **i;
 
         if (argc > 1 && argc != 4) {
@@ -355,91 +350,115 @@ int main(int argc, char *argv[]) {
 
         umask(0022);
 
-        if (parse_proc_cmdline() < 0)
+        if (parse_proc_cmdline(&arg_proc_cmdline_disks, &arg_proc_cmdline_keyfile) < 0)
                 return EXIT_FAILURE;
 
-        if (!arg_enabled) {
-                r = EXIT_SUCCESS;
-                goto finish;
-        }
+        if (!arg_enabled)
+                return EXIT_SUCCESS;
 
-        STRV_FOREACH(i, arg_proc_cmdline_disks) {
-                char *name, *device;
-                const char *p = *i;
+        if (arg_read_crypttab) {
+                struct stat st;
 
-                if (startswith(p, "luks-"))
-                        p += 5;
+                f = fopen("/etc/crypttab", "re");
+                if (!f) {
+                        if (errno == ENOENT)
+                                r = EXIT_SUCCESS;
+                        else {
+                                r = EXIT_FAILURE;
+                                log_error("Failed to open /etc/crypttab: %m");
+                        }
 
-                name = strappend("luks-", p);
-                device = strappend("UUID=", p);
+                        goto next;
+                }
 
-                if (!name || !device) {
-                        log_oom();
+                if (fstat(fileno(f), &st) < 0) {
+                        log_error("Failed to stat /etc/crypttab: %m");
                         r = EXIT_FAILURE;
-                        free(name);
-                        free(device);
-                        goto finish;
+                        goto next;
                 }
 
-                if (create_disk(name, device, NULL, NULL) < 0)
-                        r = EXIT_FAILURE;
+                if (st.st_mode & 0005)
+                        log_warning("/etc/crypttab is world-readable. This is usually not a good idea.");
 
-                free(name);
-                free(device);
-        }
+                for (;;) {
+                        char line[LINE_MAX], *l;
+                        _cleanup_free_ char *name = NULL, *device = NULL, *password = NULL, *options = NULL;
+                        int k;
 
-        if (!arg_read_crypttab)
-                return r;
+                        if (!fgets(line, sizeof(line), f))
+                                break;
 
-        f = fopen("/etc/crypttab", "re");
-        if (!f) {
+                        n++;
 
-                if (errno == ENOENT)
-                        r = EXIT_SUCCESS;
-                else {
-                        r = EXIT_FAILURE;
-                        log_error("Failed to open /etc/crypttab: %m");
-                }
+                        l = strstrip(line);
+                        if (*l == '#' || *l == 0)
+                                continue;
 
-                goto finish;
-        }
+                        k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &password, &options);
+                        if (k < 2 || k > 4) {
+                                log_error("Failed to parse /etc/crypttab:%u, ignoring.", n);
+                                r = EXIT_FAILURE;
+                                continue;
+                        }
 
-        for (;;) {
-                char line[LINE_MAX], *l;
-                char *name = NULL, *device = NULL, *password = NULL, *options = NULL;
-                int k;
+                        if (arg_proc_cmdline_disks) {
+                                /*
+                                  If luks UUIDs are specified on the kernel command line, use them as a filter
+                                  for /etc/crypttab and only generate units for those.
+                                */
+                                STRV_FOREACH(i, arg_proc_cmdline_disks) {
+                                        _cleanup_free_ char *proc_device = NULL, *proc_name = NULL;
+                                        const char *p = *i;
 
-                if (!fgets(line, sizeof(line), f))
-                        break;
+                                        if (startswith(p, "luks-"))
+                                                p += 5;
 
-                n++;
+                                        proc_name = strappend("luks-", p);
+                                        proc_device = strappend("UUID=", p);
 
-                l = strstrip(line);
-                if (*l == '#' || *l == 0)
-                        continue;
+                                        if (!proc_name || !proc_device)
+                                                return log_oom();
 
-                k = sscanf(l, "%ms %ms %ms %ms", &name, &device, &password, &options);
-                if (k < 2 || k > 4) {
-                        log_error("Failed to parse /etc/crypttab:%u, ignoring.", n);
-                        r = EXIT_FAILURE;
-                        goto next;
+                                        if (streq(proc_device, device) || streq(proc_name, name)) {
+                                                if (create_disk(name, device, password, options) < 0)
+                                                        r = EXIT_FAILURE;
+
+                                                if (strv_extend(&arg_proc_cmdline_disks_done, p) < 0)
+                                                        return log_oom();
+                                        }
+                                }
+                        } else {
+                                if (create_disk(name, device, password, options) < 0)
+                                        r = EXIT_FAILURE;
+                        }
                 }
+        }
 
-                if (create_disk(name, device, password, options) < 0)
-                        r = EXIT_FAILURE;
+next:
+        STRV_FOREACH(i, arg_proc_cmdline_disks) {
+                /*
+                  Generate units for those UUIDs, which were specified
+                  on the kernel command line and not yet written.
+                */
 
-        next:
-                free(name);
-                free(device);
-                free(password);
-                free(options);
-        }
+                _cleanup_free_ char *name = NULL, *device = NULL;
+                const char *p = *i;
 
-finish:
-        if (f)
-                fclose(f);
+                if (startswith(p, "luks-"))
+                        p += 5;
+
+                if (strv_contains(arg_proc_cmdline_disks_done, p))
+                        continue;
 
-        strv_free(arg_proc_cmdline_disks);
+                name = strappend("luks-", p);
+                device = strappend("UUID=", p);
+
+                if (!name || !device)
+                        return log_oom();
+
+                if (create_disk(name, device, arg_proc_cmdline_keyfile, "timeout=0") < 0)
+                        r = EXIT_FAILURE;
+        }
 
         return r;
 }