diff options
| -rw-r--r-- | src/bus-proxyd/bus-policy.c | 156 | ||||
| -rw-r--r-- | src/bus-proxyd/bus-policy.h | 2 |
2 files changed, 158 insertions, 0 deletions
diff --git a/src/bus-proxyd/bus-policy.c b/src/bus-proxyd/bus-policy.c index e870fbc948..151d679f6b 100644 --- a/src/bus-proxyd/bus-policy.c +++ b/src/bus-proxyd/bus-policy.c @@ -24,6 +24,7 @@ #include "strv.h" #include "conf-files.h" #include "bus-internal.h" +#include "bus-message.h" #include "bus-policy.h" static void policy_item_free(PolicyItem *i) { @@ -591,6 +592,161 @@ static int file_load(Policy *p, const char *path) { } } +static bool is_matching_name_request(sd_bus_message *m, const char *name, bool prefix) { + + char *n = NULL; + int r; + + if (!sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "RequestName")) + return false; + + r = sd_bus_message_read(m, "s", &n); + if (r < 0) + return false; + + r = sd_bus_message_rewind(m, true); + if (r < 0) + return false; + + if (prefix) + return startswith(name, n); + else + return streq_ptr(name, n); +} + +static bool is_matching_call(PolicyItem *i, sd_bus_message *m, const char *name) { + + if (i->message_type && (i->message_type != m->header->type)) + return false; + + if (i->path && (!m->path || !streq(i->path, m->path))) + return false; + + if (i->member && (!m->member || !streq(i->member, m->member))) + return false; + + if (i->interface && (!m->interface || !streq(i->interface, m->interface))) + return false; + + if (i->name && (!name || !streq(i->name, name))) + return false; + + return true; +} + +enum { + ALLOW, + DUNNO, + DENY, +}; + +static int is_permissive(PolicyItem *i) { + + return (i->type == POLICY_ITEM_ALLOW) ? ALLOW : DENY; +} + +static int check_policy_item(PolicyItem *i, sd_bus_message *m, const struct ucred *ucred) { + + switch (i->class) { + case POLICY_ITEM_SEND: + if ((m->bus->is_kernel && is_matching_call(i, m, m->destination)) || + (!m->bus->is_kernel && is_matching_call(i, m, m->sender))) + return is_permissive(i); + break; + + case POLICY_ITEM_RECV: + if ((m->bus->is_kernel && is_matching_call(i, m, m->sender)) || + (!m->bus->is_kernel && is_matching_call(i, m, m->destination))) + return is_permissive(i); + break; + + case POLICY_ITEM_OWN: + if (is_matching_name_request(m, i->name, false)) + return is_permissive(i); + break; + + case POLICY_ITEM_OWN_PREFIX: + if (is_matching_name_request(m, i->name, true)) + return is_permissive(i); + break; + + case POLICY_ITEM_USER: + if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "Hello") && + (streq_ptr(i->name, "*") || (i->uid_valid && i->uid == ucred->uid))) + return is_permissive(i); + break; + + case POLICY_ITEM_GROUP: + if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "Hello") && + (streq_ptr(i->name, "*") || (i->gid_valid && i->gid == ucred->gid))) + return is_permissive(i); + break; + + case POLICY_ITEM_IGNORE: + default: + break; + } + + return DUNNO; +} + +static int check_policy_items(PolicyItem *items, sd_bus_message *m, const struct ucred *ucred) { + + PolicyItem *i; + int r, ret = DUNNO; + + /* Check all policies in a set - a broader one might be followed by a more specific one, + * and the order of rules in policy definitions matters */ + LIST_FOREACH(items, i, items) { + r = check_policy_item(i, m, ucred); + if (r != DUNNO) + ret = r; + } + + return ret; +} + +bool policy_check(Policy *p, sd_bus_message *m, const struct ucred *ucred) { + + PolicyItem *items; + int r; + + /* + * The policy check is implemented by the following logic: + * + * 1. Check mandatory items. If the message matches any of these, it is decisive. + * 2. See if the passed ucred match against the user/group hashmaps. A matching entry is also decisive. + * 3. Consult the defaults if non of the above matched with a more specific rule. + * 4. If the message isn't caught be the defaults either, reject it. + */ + + r = check_policy_items(p->mandatory_items, m, ucred); + if (r != DUNNO) + return r == ALLOW; + + if (ucred->pid > 0) { + items = hashmap_get(p->user_items, UINT32_TO_PTR(ucred->uid)); + if (items) { + r = check_policy_items(items, m, ucred); + if (r != DUNNO) + return r == ALLOW; + } + + items = hashmap_get(p->group_items, UINT32_TO_PTR(ucred->gid)); + if (items) { + r = check_policy_items(items, m, ucred); + if (r != DUNNO) + return r == ALLOW; + } + } + + r = check_policy_items(p->default_items, m, ucred); + if (r != DUNNO) + return r == ALLOW; + + return false; +} + int policy_load(Policy *p, char **files) { char **i; int r; diff --git a/src/bus-proxyd/bus-policy.h b/src/bus-proxyd/bus-policy.h index a6ff5c37f6..2222716e7a 100644 --- a/src/bus-proxyd/bus-policy.h +++ b/src/bus-proxyd/bus-policy.h @@ -76,6 +76,8 @@ typedef struct Policy { int policy_load(Policy *p, char **files); void policy_free(Policy *p); +bool policy_check(Policy *p, sd_bus_message *m, const struct ucred *c); + void policy_dump(Policy *p); const char* policy_item_type_to_string(PolicyItemType t) _const_; |