[RFC PATCH 13/27] keys: Provide a keyctl to query a request_key authentication key

David Howells
2019-02-15T16:09:47Z

Provide a keyctl to query a request_key authentication key for situations
where this information isn't passed on the command line (such as where the
authentication key is placed in a queue instead of /sbin/request-key being
invoked):

struct keyctl_query_request_key_auth {
char operation[32];
uid_t fsuid;
gid_t fsgid;
key_serial_t target_key;
key_serial_t thread_keyring;
key_serial_t process_keyring;
key_serial_t session_keyring;
__u64 spare[1];
};

keyctl(KEYCTL_QUERY_REQUEST_KEY_AUTH,
key_serial_t key,
struct keyctl_query_request_key_auth *data);

Signed-off-by: David Howells <dhowells@redhat.com>
---

include/uapi/linux/keyctl.h | 12 ++++++++++++
security/keys/compat.c | 2 ++
security/keys/container.c | 42 ++++++++++++++++++++++++++++++++++++++++++
security/keys/internal.h | 2 ++
security/keys/keyctl.c | 4 ++++
5 files changed, 62 insertions(+)

diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h
index 85e8fef89bba..bb075ad1827d 100644
--- a/include/uapi/linux/keyctl.h
+++ b/include/uapi/linux/keyctl.h
@@ -69,6 +69,7 @@
#define KEYCTL_RESTRICT_KEYRING 29 /* Restrict keys allowed to link to a keyring */
#define KEYCTL_WATCH_KEY 30 /* Watch a key or ring of keys for changes */
#define KEYCTL_CONTAINER_INTERCEPT 31 /* Intercept upcalls inside a container */
+#define KEYCTL_QUERY_REQUEST_KEY_AUTH 32 /* Query a request_key_auth key */

/* keyctl structures */
struct keyctl_dh_params {
@@ -114,4 +115,15 @@ struct keyctl_pkey_params {
__u32 __spare[7];
};

+struct keyctl_query_request_key_auth {
+ char operation[32]; /* Operation name, typically "create" */
+ uid_t fsuid; /* UID of requester */
+ gid_t fsgid; /* GID of requester */
+ __u32 target_key; /* The key being instantiated */
+ __u32 thread_keyring; /* The requester's thread keyring */
+ __u32 process_keyring; /* The requester's process keyring */
+ __u32 session_keyring; /* The requester's session keyring */
+ __u64 spare[1];
+};
+
#endif /* _LINUX_KEYCTL_H */
diff --git a/security/keys/compat.c b/security/keys/compat.c
index 6420881e5ce7..30055fc2b629 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -164,6 +164,8 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option,
#ifdef CONFIG_CONTAINERS
case KEYCTL_CONTAINER_INTERCEPT:
return keyctl_container_intercept(arg2, compat_ptr(arg3), arg4, arg5);
+ case KEYCTL_QUERY_REQUEST_KEY_AUTH:
+ return keyctl_query_request_key_auth(arg2, compat_ptr(arg3));
#endif

default:
diff --git a/security/keys/container.c b/security/keys/container.c
index c61c43658f3b..115998e867cd 100644
--- a/security/keys/container.c
+++ b/security/keys/container.c
@@ -225,3 +225,45 @@ int queue_request_key(struct key *authkey)
kleave(" = %d", ret);
return ret;
}
+
+/*
+ * Query information about a request_key_auth key.
+ */
+long keyctl_query_request_key_auth(key_serial_t auth_id,
+ struct keyctl_query_request_key_auth __user *_data)
+{
+ struct keyctl_query_request_key_auth data;
+ struct request_key_auth *rka;
+ struct key *session;
+ key_ref_t authkey_ref;
+
+ if (auth_id <= 0 || !_data)
+ return -EINVAL;
+
+ authkey_ref = lookup_user_key(auth_id, 0, KEY_NEED_SEARCH);
+ if (IS_ERR(authkey_ref))
+ return PTR_ERR(authkey_ref);
+ rka = get_request_key_auth(key_ref_to_ptr(authkey_ref));
+
+ memset(&data, 0, sizeof(data));
+ strlcpy(data.operation, rka->op, sizeof(data.operation));
+ data.fsuid = from_kuid(current_user_ns(), rka->cred->fsuid);
+ data.fsgid = from_kgid(current_user_ns(), rka->cred->fsgid);
+ data.target_key = rka->target_key->serial;
+ data.thread_keyring = key_serial(rka->cred->thread_keyring);
+ data.process_keyring = key_serial(rka->cred->thread_keyring);
+
+ rcu_read_lock();
+ session = rcu_dereference(rka->cred->session_keyring);
+ if (!session)
+ session = rka->cred->user->session_keyring;
+ data.session_keyring = key_serial(session);
+ rcu_read_unlock();
+
+ key_ref_put(authkey_ref);
+
+ if (copy_to_user(_data, &data, sizeof(data)))
+ return -EFAULT;
+
+ return 0;
+}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index e98fca465146..9f2a6ce67d15 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -362,6 +362,8 @@ static inline long keyctl_watch_key(key_serial_t key_id, int watch_fd, int watch

#ifdef CONFIG_CONTAINERS
extern long keyctl_container_intercept(int, const char __user *, unsigned int, key_serial_t);
+extern long keyctl_query_request_key_auth(key_serial_t,
+ struct keyctl_query_request_key_auth __user *);
#endif

/*
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 38ff33431f33..a19efc60944d 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1863,6 +1863,10 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
(const char __user *)arg3,
(unsigned int)arg4,
(key_serial_t)arg5);
+ case KEYCTL_QUERY_REQUEST_KEY_AUTH:
+ return keyctl_query_request_key_auth(
+ (key_serial_t)arg2,
+ (struct keyctl_query_request_key_auth __user *)arg3);
#endif