X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fbus-proxyd%2Fbus-proxyd.c;h=50ffd0ac1620e76a4a7b8b1b9b68c77e1de8cc69;hb=78f9b196ab9671ceb625cd2abf90629ed201c24f;hp=4df2fb10afd5adc5425b3e4c7f072ff98e06891b;hpb=64e96a194d9fb8e9e69769bf88f067fadf9acce7;p=elogind.git diff --git a/src/bus-proxyd/bus-proxyd.c b/src/bus-proxyd/bus-proxyd.c index 4df2fb10a..50ffd0ac1 100644 --- a/src/bus-proxyd/bus-proxyd.c +++ b/src/bus-proxyd/bus-proxyd.c @@ -51,8 +51,6 @@ static char *arg_command_line_buffer = NULL; static bool arg_drop_privileges = false; static char **arg_configuration = NULL; -static Hashmap *names_hash = NULL; - static int help(void) { printf("%s [OPTIONS...]\n\n" @@ -442,95 +440,7 @@ static int get_creds_by_message(sd_bus *bus, sd_bus_message *m, uint64_t mask, s return get_creds_by_name(bus, name, mask, _creds, error); } -static int process_policy(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred) { - int r; - char **name; - char **names_strv; - bool granted = false; - Iterator i; - - assert(a); - assert(b); - assert(m); - - if (!policy) - return 0; - - if (b->is_kernel) { - - /* The message came from the kernel, and is sent to our legacy client. */ - r = sd_bus_creds_get_well_known_names(&m->creds, &names_strv); - if (r < 0) - return r; - - STRV_FOREACH(name, names_strv) { - if (policy_check_send(policy, ucred, m->header->type, *name, m->path, m->interface, m->member)) { - r = free_and_strdup(&m->destination_ptr, *name); - if (r < 0) - break; - - granted = true; - break; - } - } - - if (r < 0) - return r; - - if (!granted) - return -EPERM; - - granted = false; - - HASHMAP_FOREACH(name, names_hash, i) { - if (policy_check_recv(policy, ucred, m->header->type, *name, m->path, m->interface, m->member)) - return 0; - } - - return -EPERM; - } else { - sd_bus_creds *bus_creds; - - /* The message came from the legacy client, and is sent to kdbus. */ - r = sd_bus_get_name_creds(a, m->destination, SD_BUS_CREDS_WELL_KNOWN_NAMES, &bus_creds); - if (r < 0) - return r; - - STRV_FOREACH(name, names_strv) { - if (policy_check_send(policy, ucred, m->header->type, *name, m->path, m->interface, m->member)) { - r = free_and_strdup(&m->destination_ptr, *name); - if (r < 0) - break; - - r = bus_kernel_parse_unique_name(m->sender, &m->verify_destination_id); - if (r < 0) - break; - - granted = true; - break; - } - } - - if (r < 0) - return r; - - if (!granted) - return -EPERM; - - granted = false; - - HASHMAP_FOREACH(name, names_hash, i) { - if (policy_check_recv(policy, ucred, m->header->type, *name, m->path, m->interface, m->member)) - return 0; - } - - return -EPERM; - } - - return 0; -} - -static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred) { +static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred, Set *owned_names) { int r; assert(a); @@ -883,7 +793,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *polic return synthetic_reply_method_errno(m, r, NULL); } - hashmap_remove(names_hash, name); + set_remove(owned_names, (char*) name); return synthetic_reply_method_return(m, "u", BUS_NAME_RELEASED); @@ -909,7 +819,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *polic if (r < 0) return synthetic_reply_method_errno(m, r, NULL); - if (policy && !policy_check_own(policy, ucred, name)) + if (policy && !policy_check_own(policy, ucred->uid, ucred->gid, name)) return synthetic_reply_method_errno(m, -EPERM, NULL); if ((flags & ~(BUS_NAME_ALLOW_REPLACEMENT|BUS_NAME_REPLACE_EXISTING|BUS_NAME_DO_NOT_QUEUE)) != 0) @@ -923,21 +833,24 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *polic if (!(flags & BUS_NAME_DO_NOT_QUEUE)) param |= SD_BUS_NAME_QUEUE; + r = set_put_strdup(owned_names, name); + if (r < 0) + return synthetic_reply_method_errno(m, r, NULL); + r = sd_bus_request_name(a, name, param); if (r < 0) { - if (r == -EEXIST) - return synthetic_reply_method_return(m, "u", BUS_NAME_EXISTS); if (r == -EALREADY) return synthetic_reply_method_return(m, "u", BUS_NAME_ALREADY_OWNER); + + set_remove(owned_names, (char*) name); + + if (r == -EEXIST) + return synthetic_reply_method_return(m, "u", BUS_NAME_EXISTS); return synthetic_reply_method_errno(m, r, NULL); } in_queue = (r == 0); - r = hashmap_put(names_hash, name, NULL); - if (r < 0) - return synthetic_reply_method_errno(m, r, NULL); - if (in_queue) return synthetic_reply_method_return(m, "u", BUS_NAME_IN_QUEUE); @@ -1049,7 +962,166 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *polic } } -static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred, bool *got_hello) { +static int process_policy(sd_bus *from, sd_bus *to, sd_bus_message *m, Policy *policy, const struct ucred *our_ucred, Set *owned_names) { + int r; + + assert(from); + assert(to); + assert(m); + + if (!policy) + return 0; + + if (from->is_kernel) { + uid_t sender_uid = (uid_t) -1; + gid_t sender_gid = (gid_t) -1; + char **sender_names = NULL; + bool granted = false; + + /* Driver messages are always OK */ + if (streq_ptr(m->sender, "org.freedesktop.DBus")) + return 0; + + /* The message came from the kernel, and is sent to our legacy client. */ + r = sd_bus_creds_get_well_known_names(&m->creds, &sender_names); + if (r < 0) + return r; + + (void) sd_bus_creds_get_uid(&m->creds, &sender_uid); + (void) sd_bus_creds_get_gid(&m->creds, &sender_gid); + + /* First check whether the sender can send the message to our name */ + if (set_isempty(owned_names)) { + if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, NULL, m->path, m->interface, m->member)) + granted = true; + } else { + Iterator i; + char *n; + + SET_FOREACH(n, owned_names, i) + if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, n, m->path, m->interface, m->member)) { + granted = true; + break; + } + } + + if (granted) { + /* Then check whether us, the recipient can recieve from the sender's name */ + if (strv_isempty(sender_names)) { + if (policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, m->path, m->interface, m->member)) + return 0; + } else { + char **n; + + STRV_FOREACH(n, sender_names) { + if (policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, *n, m->path, m->interface, m->member)) + return 0; + } + } + } + + /* Return an error back to the caller */ + if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) + return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_ACCESS_DENIED, "Access prohibited by XML receiver policy."); + + /* Return 1, indicating that the message shall not be processed any further */ + return 1; + } + + if (to->is_kernel) { + _cleanup_bus_creds_unref_ sd_bus_creds *destination_creds = NULL; + uid_t destination_uid = (uid_t) -1; + gid_t destination_gid = (gid_t) -1; + const char *destination_unique = NULL; + char **destination_names = NULL; + bool granted = false; + + /* Driver messages are always OK */ + if (streq_ptr(m->destination, "org.freedesktop.DBus")) + return 0; + + /* The message came from the legacy client, and is sent to kdbus. */ + if (m->destination) { + r = sd_bus_get_name_creds(to, m->destination, + SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME| + SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|SD_BUS_CREDS_PID, &destination_creds); + if (r < 0) + return r; + + r = sd_bus_creds_get_well_known_names(destination_creds, &destination_names); + if (r < 0) + return r; + + r = sd_bus_creds_get_unique_name(destination_creds, &destination_unique); + if (r < 0) + return r; + + (void) sd_bus_creds_get_uid(destination_creds, &destination_uid); + (void) sd_bus_creds_get_gid(destination_creds, &destination_gid); + } + + /* First check if we, the sender can send to this name */ + if (strv_isempty(destination_names)) { + if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, m->path, m->interface, m->member)) + granted = true; + } else { + char **n; + + STRV_FOREACH(n, destination_names) { + if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, *n, m->path, m->interface, m->member)) { + + /* If we made a receiver decision, + then remember which name's policy + we used, and to which unique ID it + mapped when we made the + decision. Then, let's pass this to + the kernel when sending the + message, so that it refuses the + operation should the name and + unique ID not map to each other + anymore. */ + + r = free_and_strdup(&m->destination_ptr, *n); + if (r < 0) + return r; + + r = bus_kernel_parse_unique_name(destination_unique, &m->verify_destination_id); + if (r < 0) + break; + + granted = true; + break; + } + } + } + + /* Then check if the recipient can receive from our name */ + if (granted) { + if (set_isempty(owned_names)) { + if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, NULL, m->path, m->interface, m->member)) + return 0; + } else { + Iterator i; + char *n; + + SET_FOREACH(n, owned_names, i) + if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, n, m->path, m->interface, m->member)) + return 0; + } + } + + /* Return an error back to the caller */ + if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) + return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_ACCESS_DENIED, "Access prohibited by XML sender policy."); + + /* Return 1, indicating that the message shall not be processed any further */ + return 1; + } + + return 0; +} + +static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, bool *got_hello) { _cleanup_bus_message_unref_ sd_bus_message *n = NULL; bool is_hello; int r; @@ -1081,11 +1153,6 @@ static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy return -EIO; } - if (policy && !policy_check_hello(policy, ucred)) { - log_error("Policy denied HELLO"); - return -EPERM; - } - *got_hello = true; if (!a->is_kernel) @@ -1192,7 +1259,6 @@ static int patch_sender(sd_bus *a, sd_bus_message *m) { int main(int argc, char *argv[]) { - _cleanup_bus_creds_unref_ sd_bus_creds *bus_creds = NULL; _cleanup_bus_close_unref_ sd_bus *a = NULL, *b = NULL; sd_id128_t server_id; int r, in_fd, out_fd; @@ -1200,7 +1266,8 @@ int main(int argc, char *argv[]) { bool is_unix; struct ucred ucred = {}; _cleanup_free_ char *peersec = NULL; - Policy policy = {}; + Policy policy_buffer = {}, *policy = NULL; + _cleanup_set_free_free_ Set *owned_names = NULL; log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); log_parse_environment(); @@ -1210,14 +1277,6 @@ int main(int argc, char *argv[]) { if (r <= 0) goto finish; - r = policy_load(&policy, arg_configuration); - if (r < 0) { - log_error("Failed to load policy: %s", strerror(-r)); - goto finish; - } - - /* policy_dump(&policy); */ - r = sd_listen_fds(0); if (r == 0) { in_fd = STDIN_FILENO; @@ -1255,8 +1314,8 @@ int main(int argc, char *argv[]) { goto finish; } - names_hash = hashmap_new(&string_hash_ops); - if (!names_hash) { + owned_names = set_new(&string_hash_ops); + if (!owned_names) { log_oom(); goto finish; } @@ -1285,6 +1344,12 @@ int main(int argc, char *argv[]) { goto finish; } + r = sd_bus_negotiate_creds(a, true, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|SD_BUS_CREDS_SELINUX_CONTEXT); + if (r < 0) { + log_error("Failed to set credential negotiation: %s", strerror(-r)); + goto finish; + } + if (ucred.pid > 0) { a->fake_pids.pid = ucred.pid; a->fake_pids_valid = true; @@ -1319,10 +1384,41 @@ int main(int argc, char *argv[]) { goto finish; } - r = sd_bus_get_owner_creds(a, SD_BUS_CREDS_UID, &bus_creds); - if (r < 0) { - log_error("Failed to get bus creds: %s", strerror(-r)); - goto finish; + if (a->is_kernel) { + _cleanup_bus_creds_unref_ sd_bus_creds *bus_creds = NULL; + uid_t bus_uid; + + r = sd_bus_get_owner_creds(a, SD_BUS_CREDS_UID, &bus_creds); + if (r < 0) { + log_error("Failed to get bus creds: %s", strerror(-r)); + goto finish; + } + + r = sd_bus_creds_get_uid(bus_creds, &bus_uid); + if (r < 0) { + log_error("Failed to get bus owner UID: %s", strerror(-r)); + goto finish; + } + + if (bus_uid == 0) { + /* We only enforce the old XML policy on + * kernel busses owned by root users. */ + + r = policy_load(&policy_buffer, arg_configuration); + if (r < 0) { + log_error("Failed to load policy: %s", strerror(-r)); + goto finish; + } + + if (!policy_check_hello(&policy_buffer, ucred.uid, ucred.gid)) { + log_error("Policy denied connection"); + r = -EPERM; + goto finish; + } + + policy_dump(&policy_buffer); + policy = &policy_buffer; + } } r = sd_bus_new(&b); @@ -1349,6 +1445,12 @@ int main(int argc, char *argv[]) { goto finish; } + r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|SD_BUS_CREDS_SELINUX_CONTEXT); + if (r < 0) { + log_error("Failed to set credential negotiation: %s", strerror(-r)); + goto finish; + } + r = sd_bus_set_anonymous(b, true); if (r < 0) { log_error("Failed to set anonymous authentication: %s", strerror(-r)); @@ -1428,6 +1530,8 @@ int main(int argc, char *argv[]) { int k; if (got_hello) { + /* Read messages from bus, to pass them on to our client */ + r = sd_bus_process(a, &m); if (r < 0) { /* treat 'connection reset by peer' as clean exit condition */ @@ -1440,6 +1544,8 @@ int main(int argc, char *argv[]) { } if (m) { + bool processed = false; + /* We officially got EOF, let's quit */ if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) { r = 0; @@ -1455,16 +1561,31 @@ int main(int argc, char *argv[]) { patch_sender(a, m); - k = sd_bus_send(b, m, NULL); - if (k < 0) { - if (k == -ECONNRESET) - r = 0; - else { + if (policy) { + k = process_policy(a, b, m, policy, &ucred, owned_names); + if (k < 0) { r = k; - log_error("Failed to send message: %s", strerror(-r)); + log_error("Failed to process policy: %s", strerror(-r)); + goto finish; + } else if (k > 0) { + r = 1; + processed = true; } + } - goto finish; + if (!processed) { + k = sd_bus_send(b, m, NULL); + if (k < 0) { + if (k == -ECONNRESET) + r = 0; + else { + r = k; + log_error("Failed to send message to client: %s", strerror(-r)); + } + + goto finish; + } else + r = 1; } } @@ -1472,6 +1593,7 @@ int main(int argc, char *argv[]) { continue; } + /* Read messages from our client, to pass them on to the bus */ r = sd_bus_process(b, &m); if (r < 0) { /* treat 'connection reset by peer' as clean exit condition */ @@ -1484,15 +1606,7 @@ int main(int argc, char *argv[]) { } if (m) { - Policy *p = NULL; - uid_t uid; - - assert_se(sd_bus_creds_get_uid(bus_creds, &uid) == 0); - -/* - if (uid == 0 || uid != ucred.uid) - p = &policy; -*/ + bool processed = false; /* We officially got EOF, let's quit */ if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) { @@ -1500,53 +1614,61 @@ int main(int argc, char *argv[]) { goto finish; } - k = process_hello(a, b, m, p, &ucred, &got_hello); + k = process_hello(a, b, m, &got_hello); if (k < 0) { r = k; log_error("Failed to process HELLO: %s", strerror(-r)); goto finish; + } else if (k > 0) { + processed = true; + r = 1; } - if (k > 0) - r = k; - else { - k = process_driver(a, b, m, p, &ucred); + if (!processed) { + k = process_driver(a, b, m, policy, &ucred, owned_names); if (k < 0) { r = k; log_error("Failed to process driver calls: %s", strerror(-r)); goto finish; + } else if (k > 0) { + processed = true; + r = 1; } - if (k > 0) - r = k; - else { - bool retry; - - do { - retry = false; + if (!processed) { - k = process_policy(a, b, m, p, &ucred); - if (k < 0) { - r = k; - log_error("Failed to process policy: %s", strerror(-r)); - goto finish; + for (;;) { + if (policy) { + k = process_policy(b, a, m, policy, &ucred, owned_names); + if (k < 0) { + r = k; + log_error("Failed to process policy: %s", strerror(-r)); + goto finish; + } else if (k > 0) { + processed = true; + r = 1; + break; + } } k = sd_bus_send(a, m, NULL); if (k < 0) { - if (k == -ECONNRESET) + if (k == -EREMCHG) + /* The name database changed since the policy check, hence let's check again */ + continue; + else if (k == -ECONNRESET) r = 0; - else if (k == -EREMCHG) - retry = true; else { r = k; - log_error("Failed to send message: %s", strerror(-r)); + log_error("Failed to send message to bus: %s", strerror(-r)); } - if (!retry) - goto finish; - } - } while (retry); + goto finish; + } else + r = 1; + + break; + } } } } @@ -1620,9 +1742,8 @@ finish: "STOPPING=1\n" "STATUS=Shutting down."); - policy_free(&policy); + policy_free(&policy_buffer); strv_free(arg_configuration); - hashmap_free(names_hash); free(arg_address); return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;