]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - src/shared/dissect-image.c
dissect-image: Improve error messages
[thirdparty/systemd.git] / src / shared / dissect-image.c
index 6b0e5fe24847b701eba7dbdd001a011d9f065c71..a0832c98281faffdbd3dbbc9ac24141b86d6f0b4 100644 (file)
@@ -60,6 +60,7 @@
 #include "openssl-util.h"
 #include "os-util.h"
 #include "path-util.h"
+#include "proc-cmdline.h"
 #include "process-util.h"
 #include "raw-clone.h"
 #include "resize-fs.h"
@@ -267,16 +268,8 @@ int probe_filesystem_full(
         (void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
 
         if (fstype) {
-                char *t;
-
                 log_debug("Probed fstype '%s' on partition %s.", fstype, path);
-
-                t = strdup(fstype);
-                if (!t)
-                        return -ENOMEM;
-
-                *ret_fstype = t;
-                return 1;
+                return strdup_to_full(ret_fstype, fstype);
         }
 
 not_found:
@@ -799,7 +792,7 @@ static int dissect_image(
                         if (suuid) {
                                 /* blkid will return FAT's serial number as UUID, hence it is quite possible
                                  * that parsing this will fail. We'll ignore the ID, since it's just too
-                                 * short to be useful as tru identifier. */
+                                 * short to be useful as true identifier. */
                                 r = sd_id128_from_string(suuid, &uuid);
                                 if (r < 0)
                                         log_debug_errno(r, "Failed to parse file system UUID '%s', ignoring: %m", suuid);
@@ -2144,7 +2137,7 @@ int dissected_image_mount(
 
         if (userns_fd < 0 && need_user_mapping(uid_shift, uid_range) && FLAGS_SET(flags, DISSECT_IMAGE_MOUNT_IDMAPPED)) {
 
-                my_userns_fd = make_userns(uid_shift, uid_range, UID_INVALID, REMOUNT_IDMAPPING_HOST_ROOT);
+                my_userns_fd = make_userns(uid_shift, uid_range, UID_INVALID, UID_INVALID, REMOUNT_IDMAPPING_HOST_ROOT);
                 if (my_userns_fd < 0)
                         return my_userns_fd;
 
@@ -2285,19 +2278,19 @@ int dissected_image_mount_and_warn(
 
         r = dissected_image_mount(m, where, uid_shift, uid_range, userns_fd, flags);
         if (r == -ENXIO)
-                return log_error_errno(r, "Not root file system found in image.");
+                return log_error_errno(r, "Failed to mount image: No root file system found in image.");
         if (r == -EMEDIUMTYPE)
-                return log_error_errno(r, "No suitable os-release/extension-release file in image found.");
+                return log_error_errno(r, "Failed to mount image: No suitable os-release/extension-release file in image found.");
         if (r == -EUNATCH)
-                return log_error_errno(r, "Encrypted file system discovered, but decryption not requested.");
+                return log_error_errno(r, "Failed to mount image: Encrypted file system discovered, but decryption not requested.");
         if (r == -EUCLEAN)
-                return log_error_errno(r, "File system check on image failed.");
+                return log_error_errno(r, "Failed to mount image: File system check on image failed.");
         if (r == -EBUSY)
-                return log_error_errno(r, "File system already mounted elsewhere.");
+                return log_error_errno(r, "Failed to mount image: File system already mounted elsewhere.");
         if (r == -EAFNOSUPPORT)
-                return log_error_errno(r, "File system type not supported or not known.");
+                return log_error_errno(r, "Failed to mount image: File system type not supported or not known.");
         if (r == -EIDRM)
-                return log_error_errno(r, "File system is too uncommon, refused.");
+                return log_error_errno(r, "Failed to mount image: File system is too uncommon, refused.");
         if (r < 0)
                 return log_error_errno(r, "Failed to mount image: %m");
 
@@ -2537,7 +2530,35 @@ static char* dm_deferred_remove_clean(char *name) {
 }
 DEFINE_TRIVIAL_CLEANUP_FUNC(char *, dm_deferred_remove_clean);
 
-static int validate_signature_userspace(const VeritySettings *verity) {
+static int validate_signature_userspace(const VeritySettings *verity, DissectImageFlags flags) {
+        int r;
+
+        if (!FLAGS_SET(flags, DISSECT_IMAGE_ALLOW_USERSPACE_VERITY)) {
+                log_debug("Userspace dm-verity signature authentication disabled via flag.");
+                return 0;
+        }
+
+        r = secure_getenv_bool("SYSTEMD_ALLOW_USERSPACE_VERITY");
+        if (r < 0 && r != -ENXIO) {
+                log_debug_errno(r, "Failed to parse $SYSTEMD_ALLOW_USERSPACE_VERITY environment variable, refusing userspace dm-verity signature authentication.");
+                return 0;
+        }
+        if (!r) {
+                log_debug("Userspace dm-verity signature authentication disabled via $SYSTEMD_ALLOW_USERSPACE_VERITY environment variable.");
+                return 0;
+        }
+
+        bool b;
+        r = proc_cmdline_get_bool("systemd.allow_userspace_verity", PROC_CMDLINE_TRUE_WHEN_MISSING, &b);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to parse systemd.allow_userspace_verity= kernel command line option, refusing userspace dm-verity signature authentication.");
+                return 0;
+        }
+        if (!b) {
+                log_debug("Userspace dm-verity signature authentication disabled via systemd.allow_userspace_verity= kernel command line variable.");
+                return 0;
+        }
+
 #if HAVE_OPENSSL
         _cleanup_(sk_X509_free_allp) STACK_OF(X509) *sk = NULL;
         _cleanup_strv_free_ char **certs = NULL;
@@ -2546,7 +2567,6 @@ static int validate_signature_userspace(const VeritySettings *verity) {
         _cleanup_(BIO_freep) BIO *bio = NULL; /* 'bio' must be freed first, 's' second, hence keep this order
                                                * of declaration in place, please */
         const unsigned char *d;
-        int r;
 
         assert(verity);
         assert(verity->root_hash);
@@ -2618,7 +2638,8 @@ static int validate_signature_userspace(const VeritySettings *verity) {
 static int do_crypt_activate_verity(
                 struct crypt_device *cd,
                 const char *name,
-                const VeritySettings *verity) {
+                const VeritySettings *verity,
+                DissectImageFlags flags) {
 
         bool check_signature;
         int r, k;
@@ -2628,7 +2649,7 @@ static int do_crypt_activate_verity(
         assert(verity);
 
         if (verity->root_hash_sig) {
-                r = getenv_bool_secure("SYSTEMD_DISSECT_VERITY_SIGNATURE");
+                r = secure_getenv_bool("SYSTEMD_DISSECT_VERITY_SIGNATURE");
                 if (r < 0 && r != -ENXIO)
                         log_debug_errno(r, "Failed to parse $SYSTEMD_DISSECT_VERITY_SIGNATURE");
 
@@ -2663,7 +2684,7 @@ static int do_crypt_activate_verity(
 
                 /* Preferably propagate the original kernel error, so that the fallback logic can work,
                  * as the device-mapper is finicky around concurrent activations of the same volume */
-                k = validate_signature_userspace(verity);
+                k = validate_signature_userspace(verity, flags);
                 if (k < 0)
                         return r < 0 ? r : k;
                 if (k == 0)
@@ -2784,7 +2805,7 @@ static int verity_partition(
                         goto check; /* The device already exists. Let's check it. */
 
                 /* The symlink to the device node does not exist yet. Assume not activated, and let's activate it. */
-                r = do_crypt_activate_verity(cd, name, verity);
+                r = do_crypt_activate_verity(cd, name, verity, flags);
                 if (r >= 0)
                         goto try_open; /* The device is activated. Let's open it. */
                 /* libdevmapper can return EINVAL when the device is already in the activation stage.
@@ -2794,7 +2815,9 @@ static int verity_partition(
                  * https://gitlab.com/cryptsetup/cryptsetup/-/merge_requests/96 */
                 if (r == -EINVAL && FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE))
                         break;
-                if (r == -ENODEV) /* Volume is being opened but not ready, crypt_init_by_name would fail, try to open again */
+                /* Volume is being opened but not ready, crypt_init_by_name would fail, try to open again if
+                 * sharing is enabled. */
+                if (r == -ENODEV && FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE))
                         goto try_again;
                 if (!IN_SET(r,
                             -EEXIST, /* Volume has already been opened and ready to be used. */
@@ -2940,7 +2963,9 @@ int dissected_image_decrypt(
 
                 k = partition_verity_of(i);
                 if (k >= 0) {
-                        r = verity_partition(i, p, m->partitions + k, verity, flags | DISSECT_IMAGE_VERITY_SHARE, d);
+                        flags |= getenv_bool("SYSTEMD_VERITY_SHARING") != 0 ? DISSECT_IMAGE_VERITY_SHARE : 0;
+
+                        r = verity_partition(i, p, m->partitions + k, verity, flags, d);
                         if (r < 0)
                                 return r;
                 }
@@ -2985,9 +3010,16 @@ int dissected_image_decrypt_interactively(
                         return log_error_errno(SYNTHETIC_ERRNO(EKEYREJECTED),
                                                "Too many retries.");
 
-                z = strv_free(z);
+                z = strv_free_erase(z);
 
-                r = ask_password_auto("Please enter image passphrase:", NULL, "dissect", "dissect", "dissect.passphrase", USEC_INFINITY, 0, &z);
+                static const AskPasswordRequest req = {
+                        .message = "Please enter image passphrase:",
+                        .id = "dissect",
+                        .keyring = "dissect",
+                        .credential = "dissect.passphrase",
+                };
+
+                r = ask_password_auto(&req, USEC_INFINITY, /* flags= */ 0, &z);
                 if (r < 0)
                         return log_error_errno(r, "Failed to query for passphrase: %m");
 
@@ -3089,7 +3121,7 @@ int verity_settings_load(
         if (is_device_path(image))
                 return 0;
 
-        r = getenv_bool_secure("SYSTEMD_DISSECT_VERITY_SIDECAR");
+        r = secure_getenv_bool("SYSTEMD_DISSECT_VERITY_SIDECAR");
         if (r < 0 && r != -ENXIO)
                 log_debug_errno(r, "Failed to parse $SYSTEMD_DISSECT_VERITY_SIDECAR, ignoring: %m");
         if (r == 0)
@@ -3166,7 +3198,7 @@ int verity_settings_load(
                 }
 
                 if (text) {
-                        r = unhexmem(text, strlen(text), &root_hash, &root_hash_size);
+                        r = unhexmem(text, &root_hash, &root_hash_size);
                         if (r < 0)
                                 return r;
                         if (root_hash_size < sizeof(sd_id128_t))
@@ -3274,7 +3306,7 @@ int dissected_image_load_verity_sig_partition(
         if (verity->root_hash && verity->root_hash_sig) /* Already loaded? */
                 return 0;
 
-        r = getenv_bool_secure("SYSTEMD_DISSECT_VERITY_EMBEDDED");
+        r = secure_getenv_bool("SYSTEMD_DISSECT_VERITY_EMBEDDED");
         if (r < 0 && r != -ENXIO)
                 log_debug_errno(r, "Failed to parse $SYSTEMD_DISSECT_VERITY_EMBEDDED, ignoring: %m");
         if (r == 0)
@@ -3320,7 +3352,7 @@ int dissected_image_load_verity_sig_partition(
         if (!json_variant_is_string(rh))
                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "'rootHash' field of signature JSON object is not a string.");
 
-        r = unhexmem(json_variant_string(rh), SIZE_MAX, &root_hash, &root_hash_size);
+        r = unhexmem(json_variant_string(rh), &root_hash, &root_hash_size);
         if (r < 0)
                 return log_debug_errno(r, "Failed to parse root hash field: %m");
 
@@ -3341,7 +3373,7 @@ int dissected_image_load_verity_sig_partition(
         if (!json_variant_is_string(sig))
                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "'signature' field of signature JSON object is not a string.");
 
-        r = unbase64mem(json_variant_string(sig), SIZE_MAX, &root_hash_sig, &root_hash_sig_size);
+        r = unbase64mem(json_variant_string(sig), &root_hash_sig, &root_hash_sig_size);
         if (r < 0)
                 return log_debug_errno(r, "Failed to parse signature field: %m");
 
@@ -3382,11 +3414,10 @@ int dissected_image_acquire_metadata(DissectedImage *m, DissectImageFlags extra_
         };
 
         _cleanup_strv_free_ char **machine_info = NULL, **os_release = NULL, **initrd_release = NULL, **sysext_release = NULL, **confext_release = NULL;
+        _cleanup_free_ char *hostname = NULL, *t = NULL;
         _cleanup_close_pair_ int error_pipe[2] = EBADF_PAIR;
-        _cleanup_(rmdir_and_freep) char *t = NULL;
         _cleanup_(sigkill_waitp) pid_t child = 0;
         sd_id128_t machine_id = SD_ID128_NULL;
-        _cleanup_free_ char *hostname = NULL;
         unsigned n_meta_initialized = 0;
         int fds[2 * _META_MAX], r, v;
         int has_init_system = -1;
@@ -3405,7 +3436,7 @@ int dissected_image_acquire_metadata(DissectedImage *m, DissectImageFlags extra_
                 }
         }
 
-        r = mkdtemp_malloc("/tmp/dissect-XXXXXX", &t);
+        r = get_common_dissect_directory(&t);
         if (r < 0)
                 goto finish;
 
@@ -3956,10 +3987,12 @@ int verity_dissect_and_mount(
         if (r < 0)
                 return log_debug_errno(r, "Failed to load root hash: %m");
 
-        dissect_image_flags = (verity.data_path ? DISSECT_IMAGE_NO_PARTITION_TABLE : 0) |
+        dissect_image_flags =
+                (verity.data_path ? DISSECT_IMAGE_NO_PARTITION_TABLE : 0) |
                 (relax_extension_release_check ? DISSECT_IMAGE_RELAX_EXTENSION_CHECK : 0) |
                 DISSECT_IMAGE_ADD_PARTITION_DEVICES |
-                DISSECT_IMAGE_PIN_PARTITION_DEVICES;
+                DISSECT_IMAGE_PIN_PARTITION_DEVICES |
+                DISSECT_IMAGE_ALLOW_USERSPACE_VERITY;
 
         /* Note that we don't use loop_device_make here, as the FD is most likely O_PATH which would not be
          * accepted by LOOP_CONFIGURE, so just let loop_device_make_by_path reopen it as a regular FD. */
@@ -4070,3 +4103,29 @@ int verity_dissect_and_mount(
 
         return 0;
 }
+
+int get_common_dissect_directory(char **ret) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        /* A common location we mount dissected images to. The assumption is that everyone who uses this
+         * function runs in their own private mount namespace (with mount propagation off on /run/systemd/,
+         * and thus can mount something here without affecting anyone else). */
+
+        t = strdup("/run/systemd/dissect-root");
+        if (!t)
+                return log_oom_debug();
+
+        r = mkdir_parents(t, 0755);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to create parent dirs of mount point '%s': %m", t);
+
+        r = RET_NERRNO(mkdir(t, 0000)); /* It's supposed to be overmounted, hence let's make this inaccessible */
+        if (r < 0 && r != -EEXIST)
+                return log_debug_errno(r, "Failed to create mount point '%s': %m", t);
+
+        if (ret)
+                *ret = TAKE_PTR(t);
+
+        return 0;
+}