root/net/ceph/auth_x.c
// SPDX-License-Identifier: GPL-2.0

#include <linux/ceph/ceph_debug.h>

#include <linux/err.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>

#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>
#include <linux/ceph/ceph_features.h>
#include <linux/ceph/libceph.h>
#include <linux/ceph/messenger.h>

#include "crypto.h"
#include "auth_x.h"
#include "auth_x_protocol.h"

static const u32 ticket_key_usages[] = {
        CEPHX_KEY_USAGE_TICKET_SESSION_KEY,
        CEPHX_KEY_USAGE_TICKET_BLOB,
        CEPHX_KEY_USAGE_AUTH_CONNECTION_SECRET
};

static const u32 authorizer_key_usages[] = {
        CEPHX_KEY_USAGE_AUTHORIZE,
        CEPHX_KEY_USAGE_AUTHORIZE_CHALLENGE,
        CEPHX_KEY_USAGE_AUTHORIZE_REPLY
};

static const u32 client_key_usages[] = {
        CEPHX_KEY_USAGE_TICKET_SESSION_KEY
};

static void ceph_x_validate_tickets(struct ceph_auth_client *ac, int *pneed);

static int ceph_x_is_authenticated(struct ceph_auth_client *ac)
{
        struct ceph_x_info *xi = ac->private;
        int missing;
        int need;  /* missing + need renewal */

        ceph_x_validate_tickets(ac, &need);
        missing = ac->want_keys & ~xi->have_keys;
        WARN_ON((need & missing) != missing);
        dout("%s want 0x%x have 0x%x missing 0x%x -> %d\n", __func__,
             ac->want_keys, xi->have_keys, missing, !missing);
        return !missing;
}

static int ceph_x_should_authenticate(struct ceph_auth_client *ac)
{
        struct ceph_x_info *xi = ac->private;
        int need;

        ceph_x_validate_tickets(ac, &need);
        dout("%s want 0x%x have 0x%x need 0x%x -> %d\n", __func__,
             ac->want_keys, xi->have_keys, need, !!need);
        return !!need;
}

static int __ceph_x_encrypt_offset(const struct ceph_crypto_key *key)
{
        return ceph_crypt_data_offset(key) +
               sizeof(struct ceph_x_encrypt_header);
}

static int ceph_x_encrypt_offset(const struct ceph_crypto_key *key)
{
        return sizeof(u32) + __ceph_x_encrypt_offset(key);
}

/*
 * AES: ciphertext_len | hdr | data... | padding
 * AES256KRB5: ciphertext_len | confounder | hdr | data... | hmac
 */
static int ceph_x_encrypt_buflen(const struct ceph_crypto_key *key,
                                 int data_len)
{
        int encrypt_len = sizeof(struct ceph_x_encrypt_header) + data_len;
        return sizeof(u32) + ceph_crypt_buflen(key, encrypt_len);
}

static int ceph_x_encrypt(const struct ceph_crypto_key *key, int usage_slot,
                          void *buf, int buf_len, int plaintext_len)
{
        struct ceph_x_encrypt_header *hdr;
        int ciphertext_len;
        int ret;

        hdr = buf + sizeof(u32) + ceph_crypt_data_offset(key);
        hdr->struct_v = 1;
        hdr->magic = cpu_to_le64(CEPHX_ENC_MAGIC);

        ret = ceph_crypt(key, usage_slot, true, buf + sizeof(u32),
                         buf_len - sizeof(u32), plaintext_len + sizeof(*hdr),
                         &ciphertext_len);
        if (ret)
                return ret;

        ceph_encode_32(&buf, ciphertext_len);
        return sizeof(u32) + ciphertext_len;
}

static int __ceph_x_decrypt(const struct ceph_crypto_key *key, int usage_slot,
                            void *p, int ciphertext_len)
{
        struct ceph_x_encrypt_header *hdr;
        int plaintext_len;
        int ret;

        ret = ceph_crypt(key, usage_slot, false, p, ciphertext_len,
                         ciphertext_len, &plaintext_len);
        if (ret)
                return ret;

        if (plaintext_len < sizeof(*hdr)) {
                pr_err("%s plaintext too small %d\n", __func__, plaintext_len);
                return -EINVAL;
        }

        hdr = p + ceph_crypt_data_offset(key);
        if (le64_to_cpu(hdr->magic) != CEPHX_ENC_MAGIC) {
                pr_err("%s bad magic\n", __func__);
                return -EINVAL;
        }

        return plaintext_len - sizeof(*hdr);
}

static int ceph_x_decrypt(const struct ceph_crypto_key *key, int usage_slot,
                          void **p, void *end)
{
        int ciphertext_len;
        int ret;

        ceph_decode_32_safe(p, end, ciphertext_len, e_inval);
        ceph_decode_need(p, end, ciphertext_len, e_inval);

        ret = __ceph_x_decrypt(key, usage_slot, *p, ciphertext_len);
        if (ret < 0)
                return ret;

        *p += ciphertext_len;
        return ret;

e_inval:
        return -EINVAL;
}

/*
 * get existing (or insert new) ticket handler
 */
static struct ceph_x_ticket_handler *
get_ticket_handler(struct ceph_auth_client *ac, int service)
{
        struct ceph_x_ticket_handler *th;
        struct ceph_x_info *xi = ac->private;
        struct rb_node *parent = NULL, **p = &xi->ticket_handlers.rb_node;

        while (*p) {
                parent = *p;
                th = rb_entry(parent, struct ceph_x_ticket_handler, node);
                if (service < th->service)
                        p = &(*p)->rb_left;
                else if (service > th->service)
                        p = &(*p)->rb_right;
                else
                        return th;
        }

        /* add it */
        th = kzalloc_obj(*th, GFP_NOFS);
        if (!th)
                return ERR_PTR(-ENOMEM);
        th->service = service;
        rb_link_node(&th->node, parent, p);
        rb_insert_color(&th->node, &xi->ticket_handlers);
        return th;
}

static void remove_ticket_handler(struct ceph_auth_client *ac,
                                  struct ceph_x_ticket_handler *th)
{
        struct ceph_x_info *xi = ac->private;

        dout("remove_ticket_handler %p %d\n", th, th->service);
        rb_erase(&th->node, &xi->ticket_handlers);
        ceph_crypto_key_destroy(&th->session_key);
        if (th->ticket_blob)
                ceph_buffer_put(th->ticket_blob);
        kfree(th);
}

static int process_one_ticket(struct ceph_auth_client *ac,
                              struct ceph_crypto_key *secret,
                              void **p, void *end)
{
        struct ceph_x_info *xi = ac->private;
        int type;
        u8 tkt_struct_v, blob_struct_v;
        struct ceph_x_ticket_handler *th;
        void *dp, *dend;
        int dlen;
        char is_enc;
        struct timespec64 validity;
        void *tp, *tpend;
        void **ptp;
        struct ceph_crypto_key new_session_key = { 0 };
        struct ceph_buffer *new_ticket_blob;
        time64_t new_expires, new_renew_after;
        u64 new_secret_id;
        int ret;

        ceph_decode_need(p, end, sizeof(u32) + 1, bad);

        type = ceph_decode_32(p);
        dout(" ticket type %d %s\n", type, ceph_entity_type_name(type));

        tkt_struct_v = ceph_decode_8(p);
        if (tkt_struct_v != 1)
                goto bad;

        th = get_ticket_handler(ac, type);
        if (IS_ERR(th)) {
                ret = PTR_ERR(th);
                goto out;
        }

        /* blob for me */
        dp = *p + ceph_x_encrypt_offset(secret);
        ret = ceph_x_decrypt(secret,
                             0 /* CEPHX_KEY_USAGE_TICKET_SESSION_KEY */,
                             p, end);
        if (ret < 0)
                goto out;
        dout(" decrypted %d bytes\n", ret);
        dend = dp + ret;

        ceph_decode_8_safe(&dp, dend, tkt_struct_v, bad);
        if (tkt_struct_v != 1)
                goto bad;

        ret = ceph_crypto_key_decode(&new_session_key, &dp, dend);
        if (ret)
                goto out;

        ret = ceph_crypto_key_prepare(&new_session_key, ticket_key_usages,
                                      ARRAY_SIZE(ticket_key_usages));
        if (ret)
                goto out;

        ceph_decode_need(&dp, dend, sizeof(struct ceph_timespec), bad);
        ceph_decode_timespec64(&validity, dp);
        dp += sizeof(struct ceph_timespec);
        new_expires = ktime_get_real_seconds() + validity.tv_sec;
        new_renew_after = new_expires - (validity.tv_sec / 4);
        dout(" expires=%llu renew_after=%llu\n", new_expires,
             new_renew_after);

        /* ticket blob for service */
        ceph_decode_8_safe(p, end, is_enc, bad);
        if (is_enc) {
                /* encrypted */
                tp = *p + ceph_x_encrypt_offset(&th->session_key);
                ret = ceph_x_decrypt(&th->session_key,
                                     1 /* CEPHX_KEY_USAGE_TICKET_BLOB */,
                                     p, end);
                if (ret < 0)
                        goto out;
                dout(" encrypted ticket, decrypted %d bytes\n", ret);
                ptp = &tp;
                tpend = tp + ret;
        } else {
                /* unencrypted */
                ptp = p;
                tpend = end;
        }
        ceph_decode_32_safe(ptp, tpend, dlen, bad);
        dout(" ticket blob is %d bytes\n", dlen);
        ceph_decode_need(ptp, tpend, 1 + sizeof(u64), bad);
        blob_struct_v = ceph_decode_8(ptp);
        if (blob_struct_v != 1)
                goto bad;

        new_secret_id = ceph_decode_64(ptp);
        ret = ceph_decode_buffer(&new_ticket_blob, ptp, tpend);
        if (ret)
                goto out;

        /* all is well, update our ticket */
        ceph_crypto_key_destroy(&th->session_key);
        if (th->ticket_blob)
                ceph_buffer_put(th->ticket_blob);
        th->session_key = new_session_key;
        th->ticket_blob = new_ticket_blob;
        th->secret_id = new_secret_id;
        th->expires = new_expires;
        th->renew_after = new_renew_after;
        th->have_key = true;
        dout(" got ticket service %d (%s) secret_id %lld len %d\n",
             type, ceph_entity_type_name(type), th->secret_id,
             (int)th->ticket_blob->vec.iov_len);
        xi->have_keys |= th->service;
        return 0;

bad:
        ret = -EINVAL;
out:
        ceph_crypto_key_destroy(&new_session_key);
        return ret;
}

static int ceph_x_proc_ticket_reply(struct ceph_auth_client *ac,
                                    struct ceph_crypto_key *secret,
                                    void **p, void *end)
{
        u8 reply_struct_v;
        u32 num;
        int ret;

        ceph_decode_8_safe(p, end, reply_struct_v, bad);
        if (reply_struct_v != 1)
                return -EINVAL;

        ceph_decode_32_safe(p, end, num, bad);
        dout("%d tickets\n", num);

        while (num--) {
                ret = process_one_ticket(ac, secret, p, end);
                if (ret)
                        return ret;
        }

        return 0;

bad:
        return -EINVAL;
}

/*
 * Encode and encrypt the second part (ceph_x_authorize_b) of the
 * authorizer.  The first part (ceph_x_authorize_a) should already be
 * encoded.
 */
static int encrypt_authorizer(struct ceph_x_authorizer *au,
                              u64 *server_challenge)
{
        struct ceph_x_authorize_a *msg_a;
        struct ceph_x_authorize_b *msg_b;
        void *p, *end;
        int ret;

        msg_a = au->buf->vec.iov_base;
        WARN_ON(msg_a->ticket_blob.secret_id != cpu_to_le64(au->secret_id));
        p = (void *)(msg_a + 1) + le32_to_cpu(msg_a->ticket_blob.blob_len);
        end = au->buf->vec.iov_base + au->buf->vec.iov_len;

        msg_b = p + ceph_x_encrypt_offset(&au->session_key);
        msg_b->struct_v = 2;
        msg_b->nonce = cpu_to_le64(au->nonce);
        if (server_challenge) {
                msg_b->have_challenge = 1;
                msg_b->server_challenge_plus_one =
                    cpu_to_le64(*server_challenge + 1);
        } else {
                msg_b->have_challenge = 0;
                msg_b->server_challenge_plus_one = 0;
        }

        ret = ceph_x_encrypt(&au->session_key,
                             0 /* CEPHX_KEY_USAGE_AUTHORIZE */,
                             p, end - p, sizeof(*msg_b));
        if (ret < 0)
                return ret;

        p += ret;
        if (server_challenge) {
                WARN_ON(p != end);
        } else {
                WARN_ON(p > end);
                au->buf->vec.iov_len = p - au->buf->vec.iov_base;
        }

        return 0;
}

static void ceph_x_authorizer_cleanup(struct ceph_x_authorizer *au)
{
        ceph_crypto_key_destroy(&au->session_key);
        if (au->buf) {
                ceph_buffer_put(au->buf);
                au->buf = NULL;
        }
}

static int ceph_x_build_authorizer(struct ceph_auth_client *ac,
                                   struct ceph_x_ticket_handler *th,
                                   struct ceph_x_authorizer *au)
{
        int maxlen;
        struct ceph_x_authorize_a *msg_a;
        struct ceph_x_authorize_b *msg_b;
        int ret;
        int ticket_blob_len =
                (th->ticket_blob ? th->ticket_blob->vec.iov_len : 0);

        dout("build_authorizer for %s %p\n",
             ceph_entity_type_name(th->service), au);

        ceph_crypto_key_destroy(&au->session_key);
        ret = ceph_crypto_key_clone(&au->session_key, &th->session_key);
        if (ret)
                goto out_au;

        ret = ceph_crypto_key_prepare(&au->session_key, authorizer_key_usages,
                                      ARRAY_SIZE(authorizer_key_usages));
        if (ret)
                goto out_au;

        maxlen = sizeof(*msg_a) + ticket_blob_len +
                ceph_x_encrypt_buflen(&au->session_key, sizeof(*msg_b));
        dout("  need len %d\n", maxlen);
        if (au->buf && au->buf->alloc_len < maxlen) {
                ceph_buffer_put(au->buf);
                au->buf = NULL;
        }
        if (!au->buf) {
                au->buf = ceph_buffer_new(maxlen, GFP_NOFS);
                if (!au->buf) {
                        ret = -ENOMEM;
                        goto out_au;
                }
        }
        au->service = th->service;
        WARN_ON(!th->secret_id);
        au->secret_id = th->secret_id;

        msg_a = au->buf->vec.iov_base;
        msg_a->struct_v = 1;
        msg_a->global_id = cpu_to_le64(ac->global_id);
        msg_a->service_id = cpu_to_le32(th->service);
        msg_a->ticket_blob.struct_v = 1;
        msg_a->ticket_blob.secret_id = cpu_to_le64(th->secret_id);
        msg_a->ticket_blob.blob_len = cpu_to_le32(ticket_blob_len);
        if (ticket_blob_len) {
                memcpy(msg_a->ticket_blob.blob, th->ticket_blob->vec.iov_base,
                       th->ticket_blob->vec.iov_len);
        }
        dout(" th %p secret_id %lld %lld\n", th, th->secret_id,
             le64_to_cpu(msg_a->ticket_blob.secret_id));

        get_random_bytes(&au->nonce, sizeof(au->nonce));
        ret = encrypt_authorizer(au, NULL);
        if (ret) {
                pr_err("failed to encrypt authorizer: %d", ret);
                goto out_au;
        }

        dout(" built authorizer nonce %llx len %d\n", au->nonce,
             (int)au->buf->vec.iov_len);
        return 0;

out_au:
        ceph_x_authorizer_cleanup(au);
        return ret;
}

static int ceph_x_encode_ticket(struct ceph_x_ticket_handler *th,
                                void **p, void *end)
{
        ceph_decode_need(p, end, 1 + sizeof(u64), bad);
        ceph_encode_8(p, 1);
        ceph_encode_64(p, th->secret_id);
        if (th->ticket_blob) {
                const char *buf = th->ticket_blob->vec.iov_base;
                u32 len = th->ticket_blob->vec.iov_len;

                ceph_encode_32_safe(p, end, len, bad);
                ceph_encode_copy_safe(p, end, buf, len, bad);
        } else {
                ceph_encode_32_safe(p, end, 0, bad);
        }

        return 0;
bad:
        return -ERANGE;
}

static bool need_key(struct ceph_x_ticket_handler *th)
{
        if (!th->have_key)
                return true;

        return ktime_get_real_seconds() >= th->renew_after;
}

static bool have_key(struct ceph_x_ticket_handler *th)
{
        if (th->have_key && ktime_get_real_seconds() >= th->expires) {
                dout("ticket %d (%s) secret_id %llu expired\n", th->service,
                     ceph_entity_type_name(th->service), th->secret_id);
                th->have_key = false;
        }

        return th->have_key;
}

static void ceph_x_validate_tickets(struct ceph_auth_client *ac, int *pneed)
{
        int want = ac->want_keys;
        struct ceph_x_info *xi = ac->private;
        int service;

        *pneed = ac->want_keys & ~(xi->have_keys);

        for (service = 1; service <= want; service <<= 1) {
                struct ceph_x_ticket_handler *th;

                if (!(ac->want_keys & service))
                        continue;

                if (*pneed & service)
                        continue;

                th = get_ticket_handler(ac, service);
                if (IS_ERR(th)) {
                        *pneed |= service;
                        continue;
                }

                if (need_key(th))
                        *pneed |= service;
                if (!have_key(th))
                        xi->have_keys &= ~service;
        }
}

static int ceph_x_build_request(struct ceph_auth_client *ac,
                                void *buf, void *end)
{
        struct ceph_x_info *xi = ac->private;
        int need;
        struct ceph_x_request_header *head = buf;
        void *p;
        int ret;
        struct ceph_x_ticket_handler *th =
                get_ticket_handler(ac, CEPH_ENTITY_TYPE_AUTH);

        if (IS_ERR(th))
                return PTR_ERR(th);

        ceph_x_validate_tickets(ac, &need);
        dout("%s want 0x%x have 0x%x need 0x%x\n", __func__, ac->want_keys,
             xi->have_keys, need);

        if (need & CEPH_ENTITY_TYPE_AUTH) {
                struct ceph_x_authenticate *auth = (void *)(head + 1);
                void *enc_buf = xi->auth_authorizer.enc_buf;
                struct ceph_x_challenge_blob *blob;
                u64 *u;

                p = auth + 1;
                if (p > end)
                        return -ERANGE;

                dout(" get_auth_session_key\n");
                head->op = cpu_to_le16(CEPHX_GET_AUTH_SESSION_KEY);

                if (xi->secret.type == CEPH_CRYPTO_AES) {
                        blob = enc_buf + ceph_x_encrypt_offset(&xi->secret);
                } else {
                        BUILD_BUG_ON(SHA256_DIGEST_SIZE + sizeof(*blob) >
                                     CEPHX_AU_ENC_BUF_LEN);
                        blob = enc_buf + SHA256_DIGEST_SIZE;
                }

                get_random_bytes(&auth->client_challenge, sizeof(u64));
                blob->client_challenge = auth->client_challenge;
                blob->server_challenge = cpu_to_le64(xi->server_challenge);

                if (xi->secret.type == CEPH_CRYPTO_AES) {
                        ret = ceph_x_encrypt(&xi->secret, 0 /* dummy */,
                                             enc_buf, CEPHX_AU_ENC_BUF_LEN,
                                             sizeof(*blob));
                        if (ret < 0)
                                return ret;
                } else {
                        ceph_hmac_sha256(&xi->secret, blob, sizeof(*blob),
                                         enc_buf);
                        ret = SHA256_DIGEST_SIZE;
                }

                auth->struct_v = 3;  /* nautilus+ */
                auth->key = 0;
                for (u = (u64 *)enc_buf; u + 1 <= (u64 *)(enc_buf + ret); u++)
                        auth->key ^= *(__le64 *)u;
                dout(" server_challenge %llx client_challenge %llx key %llx\n",
                     xi->server_challenge, le64_to_cpu(auth->client_challenge),
                     le64_to_cpu(auth->key));

                /* now encode the old ticket if exists */
                ret = ceph_x_encode_ticket(th, &p, end);
                if (ret < 0)
                        return ret;

                /* nautilus+: request service tickets at the same time */
                need = ac->want_keys & ~CEPH_ENTITY_TYPE_AUTH;
                WARN_ON(!need);
                ceph_encode_32_safe(&p, end, need, e_range);
                return p - buf;
        }

        if (need) {
                dout(" get_principal_session_key\n");
                ret = ceph_x_build_authorizer(ac, th, &xi->auth_authorizer);
                if (ret)
                        return ret;

                p = buf;
                ceph_encode_16_safe(&p, end, CEPHX_GET_PRINCIPAL_SESSION_KEY,
                                    e_range);
                ceph_encode_copy_safe(&p, end,
                        xi->auth_authorizer.buf->vec.iov_base,
                        xi->auth_authorizer.buf->vec.iov_len, e_range);
                ceph_encode_8_safe(&p, end, 1, e_range);
                ceph_encode_32_safe(&p, end, need, e_range);
                return p - buf;
        }

        return 0;

e_range:
        return -ERANGE;
}

static int decode_con_secret(void **p, void *end, u8 *con_secret,
                             int *con_secret_len)
{
        int len;

        ceph_decode_32_safe(p, end, len, bad);
        ceph_decode_need(p, end, len, bad);

        dout("%s len %d\n", __func__, len);
        if (con_secret) {
                if (len > CEPH_MAX_CON_SECRET_LEN) {
                        pr_err("connection secret too big %d\n", len);
                        goto bad_memzero;
                }
                memcpy(con_secret, *p, len);
                *con_secret_len = len;
        }
        memzero_explicit(*p, len);
        *p += len;
        return 0;

bad_memzero:
        memzero_explicit(*p, len);
bad:
        pr_err("failed to decode connection secret\n");
        return -EINVAL;
}

static int handle_auth_session_key(struct ceph_auth_client *ac, u64 global_id,
                                   void **p, void *end,
                                   u8 *session_key, int *session_key_len,
                                   u8 *con_secret, int *con_secret_len)
{
        struct ceph_x_info *xi = ac->private;
        struct ceph_x_ticket_handler *th;
        void *dp, *dend;
        int len;
        int ret;

        /* AUTH ticket */
        ret = ceph_x_proc_ticket_reply(ac, &xi->secret, p, end);
        if (ret)
                return ret;

        ceph_auth_set_global_id(ac, global_id);
        if (*p == end) {
                /* pre-nautilus (or didn't request service tickets!) */
                WARN_ON(session_key || con_secret);
                return 0;
        }

        th = get_ticket_handler(ac, CEPH_ENTITY_TYPE_AUTH);
        if (IS_ERR(th))
                return PTR_ERR(th);

        if (session_key) {
                memcpy(session_key, th->session_key.key, th->session_key.len);
                *session_key_len = th->session_key.len;
        }

        /* connection secret */
        ceph_decode_32_safe(p, end, len, e_inval);
        ceph_decode_need(p, end, len, e_inval);
        dout("%s connection secret blob len %d\n", __func__, len);
        if (len > 0) {
                dp = *p + ceph_x_encrypt_offset(&th->session_key);
                ret = ceph_x_decrypt(&th->session_key,
                                     2 /* CEPHX_KEY_USAGE_AUTH_CONNECTION_SECRET */,
                                     p, *p + len);
                if (ret < 0)
                        return ret;

                dout("%s decrypted %d bytes\n", __func__, ret);
                dend = dp + ret;

                ret = decode_con_secret(&dp, dend, con_secret, con_secret_len);
                if (ret)
                        return ret;
        }

        /* service tickets */
        ceph_decode_32_safe(p, end, len, e_inval);
        ceph_decode_need(p, end, len, e_inval);
        dout("%s service tickets blob len %d\n", __func__, len);
        if (len > 0) {
                ret = ceph_x_proc_ticket_reply(ac, &th->session_key,
                                               p, *p + len);
                if (ret)
                        return ret;
        }

        return 0;

e_inval:
        return -EINVAL;
}

static int ceph_x_handle_reply(struct ceph_auth_client *ac, u64 global_id,
                               void *buf, void *end,
                               u8 *session_key, int *session_key_len,
                               u8 *con_secret, int *con_secret_len)
{
        struct ceph_x_info *xi = ac->private;
        struct ceph_x_ticket_handler *th;
        int len = end - buf;
        int result;
        void *p;
        int op;
        int ret;

        if (xi->starting) {
                /* it's a hello */
                struct ceph_x_server_challenge *sc = buf;

                if (len != sizeof(*sc))
                        return -EINVAL;
                xi->server_challenge = le64_to_cpu(sc->server_challenge);
                dout("handle_reply got server challenge %llx\n",
                     xi->server_challenge);
                xi->starting = false;
                xi->have_keys &= ~CEPH_ENTITY_TYPE_AUTH;
                return -EAGAIN;
        }

        p = buf;
        ceph_decode_16_safe(&p, end, op, e_inval);
        ceph_decode_32_safe(&p, end, result, e_inval);
        dout("handle_reply op %d result %d\n", op, result);
        switch (op) {
        case CEPHX_GET_AUTH_SESSION_KEY:
                /* AUTH ticket + [connection secret] + service tickets */
                ret = handle_auth_session_key(ac, global_id, &p, end,
                                              session_key, session_key_len,
                                              con_secret, con_secret_len);
                break;

        case CEPHX_GET_PRINCIPAL_SESSION_KEY:
                th = get_ticket_handler(ac, CEPH_ENTITY_TYPE_AUTH);
                if (IS_ERR(th))
                        return PTR_ERR(th);

                /* service tickets */
                ret = ceph_x_proc_ticket_reply(ac, &th->session_key, &p, end);
                break;

        default:
                return -EINVAL;
        }
        if (ret)
                return ret;
        if (ac->want_keys == xi->have_keys)
                return 0;
        return -EAGAIN;

e_inval:
        return -EINVAL;
}

static void ceph_x_destroy_authorizer(struct ceph_authorizer *a)
{
        struct ceph_x_authorizer *au = (void *)a;

        ceph_x_authorizer_cleanup(au);
        kfree(au);
}

static int ceph_x_create_authorizer(
        struct ceph_auth_client *ac, int peer_type,
        struct ceph_auth_handshake *auth)
{
        struct ceph_x_authorizer *au;
        struct ceph_x_ticket_handler *th;
        int ret;

        th = get_ticket_handler(ac, peer_type);
        if (IS_ERR(th))
                return PTR_ERR(th);

        au = kzalloc_obj(*au, GFP_NOFS);
        if (!au)
                return -ENOMEM;

        au->base.destroy = ceph_x_destroy_authorizer;

        ret = ceph_x_build_authorizer(ac, th, au);
        if (ret) {
                kfree(au);
                return ret;
        }

        auth->authorizer = (struct ceph_authorizer *) au;
        auth->authorizer_buf = au->buf->vec.iov_base;
        auth->authorizer_buf_len = au->buf->vec.iov_len;
        auth->authorizer_reply_buf = au->enc_buf;
        auth->authorizer_reply_buf_len = CEPHX_AU_ENC_BUF_LEN;
        auth->sign_message = ac->ops->sign_message;
        auth->check_message_signature = ac->ops->check_message_signature;

        return 0;
}

static int ceph_x_update_authorizer(
        struct ceph_auth_client *ac, int peer_type,
        struct ceph_auth_handshake *auth)
{
        struct ceph_x_authorizer *au;
        struct ceph_x_ticket_handler *th;

        th = get_ticket_handler(ac, peer_type);
        if (IS_ERR(th))
                return PTR_ERR(th);

        au = (struct ceph_x_authorizer *)auth->authorizer;
        if (au->secret_id < th->secret_id) {
                int ret;

                dout("ceph_x_update_authorizer service %u secret %llu < %llu\n",
                     au->service, au->secret_id, th->secret_id);
                ret = ceph_x_build_authorizer(ac, th, au);
                if (ret)
                        return ret;

                auth->authorizer_buf = au->buf->vec.iov_base;
                auth->authorizer_buf_len = au->buf->vec.iov_len;
        }
        return 0;
}

/*
 * CephXAuthorizeChallenge
 */
static int decrypt_authorizer_challenge(struct ceph_crypto_key *secret,
                                        void *challenge, int challenge_len,
                                        u64 *server_challenge)
{
        void *dp, *dend;
        int ret;

        /* no leading len */
        ret = __ceph_x_decrypt(secret,
                               1 /* CEPHX_KEY_USAGE_AUTHORIZE_CHALLENGE */,
                               challenge, challenge_len);
        if (ret < 0)
                return ret;

        dout("%s decrypted %d bytes\n", __func__, ret);
        dp = challenge + __ceph_x_encrypt_offset(secret);
        dend = dp + ret;

        ceph_decode_skip_8(&dp, dend, e_inval);  /* struct_v */
        ceph_decode_64_safe(&dp, dend, *server_challenge, e_inval);
        dout("%s server_challenge %llu\n", __func__, *server_challenge);
        return 0;

e_inval:
        return -EINVAL;
}

static int ceph_x_add_authorizer_challenge(struct ceph_auth_client *ac,
                                           struct ceph_authorizer *a,
                                           void *challenge, int challenge_len)
{
        struct ceph_x_authorizer *au = (void *)a;
        u64 server_challenge;
        int ret;

        ret = decrypt_authorizer_challenge(&au->session_key, challenge,
                                           challenge_len, &server_challenge);
        if (ret) {
                pr_err("failed to decrypt authorize challenge: %d", ret);
                return ret;
        }

        ret = encrypt_authorizer(au, &server_challenge);
        if (ret) {
                pr_err("failed to encrypt authorizer w/ challenge: %d", ret);
                return ret;
        }

        return 0;
}

/*
 * CephXAuthorizeReply
 */
static int decrypt_authorizer_reply(struct ceph_crypto_key *secret,
                                    void **p, void *end, u64 *nonce_plus_one,
                                    u8 *con_secret, int *con_secret_len)
{
        void *dp, *dend;
        u8 struct_v;
        int ret;

        dp = *p + ceph_x_encrypt_offset(secret);
        ret = ceph_x_decrypt(secret, 2 /* CEPHX_KEY_USAGE_AUTHORIZE_REPLY */,
                             p, end);
        if (ret < 0)
                return ret;

        dout("%s decrypted %d bytes\n", __func__, ret);
        dend = dp + ret;

        ceph_decode_8_safe(&dp, dend, struct_v, e_inval);
        ceph_decode_64_safe(&dp, dend, *nonce_plus_one, e_inval);
        dout("%s nonce_plus_one %llu\n", __func__, *nonce_plus_one);
        if (struct_v >= 2) {
                ret = decode_con_secret(&dp, dend, con_secret, con_secret_len);
                if (ret)
                        return ret;
        }

        return 0;

e_inval:
        return -EINVAL;
}

static int ceph_x_verify_authorizer_reply(struct ceph_auth_client *ac,
                                          struct ceph_authorizer *a,
                                          void *reply, int reply_len,
                                          u8 *session_key, int *session_key_len,
                                          u8 *con_secret, int *con_secret_len)
{
        struct ceph_x_authorizer *au = (void *)a;
        u64 nonce_plus_one;
        int ret;

        if (session_key) {
                memcpy(session_key, au->session_key.key, au->session_key.len);
                *session_key_len = au->session_key.len;
        }

        ret = decrypt_authorizer_reply(&au->session_key, &reply,
                                       reply + reply_len, &nonce_plus_one,
                                       con_secret, con_secret_len);
        if (ret)
                return ret;

        if (nonce_plus_one != au->nonce + 1) {
                pr_err("failed to authenticate server\n");
                return -EPERM;
        }

        return 0;
}

static void ceph_x_reset(struct ceph_auth_client *ac)
{
        struct ceph_x_info *xi = ac->private;

        dout("reset\n");
        xi->starting = true;
        xi->server_challenge = 0;
}

static void ceph_x_destroy(struct ceph_auth_client *ac)
{
        struct ceph_x_info *xi = ac->private;
        struct rb_node *p;

        dout("ceph_x_destroy %p\n", ac);
        ceph_crypto_key_destroy(&xi->secret);

        while ((p = rb_first(&xi->ticket_handlers)) != NULL) {
                struct ceph_x_ticket_handler *th =
                        rb_entry(p, struct ceph_x_ticket_handler, node);
                remove_ticket_handler(ac, th);
        }

        ceph_x_authorizer_cleanup(&xi->auth_authorizer);

        kfree(ac->private);
        ac->private = NULL;
}

static void invalidate_ticket(struct ceph_auth_client *ac, int peer_type)
{
        struct ceph_x_ticket_handler *th;

        th = get_ticket_handler(ac, peer_type);
        if (IS_ERR(th))
                return;

        if (th->have_key) {
                dout("ticket %d (%s) secret_id %llu invalidated\n",
                     th->service, ceph_entity_type_name(th->service),
                     th->secret_id);
                th->have_key = false;
        }
}

static void ceph_x_invalidate_authorizer(struct ceph_auth_client *ac,
                                         int peer_type)
{
        /*
         * We are to invalidate a service ticket in the hopes of
         * getting a new, hopefully more valid, one.  But, we won't get
         * it unless our AUTH ticket is good, so invalidate AUTH ticket
         * as well, just in case.
         */
        invalidate_ticket(ac, peer_type);
        invalidate_ticket(ac, CEPH_ENTITY_TYPE_AUTH);
}

static int calc_signature(struct ceph_x_authorizer *au, struct ceph_msg *msg,
                          __le64 *psig)
{
        void *enc_buf = au->enc_buf;
        int ret;

        if (!CEPH_HAVE_FEATURE(msg->con->peer_features, CEPHX_V2)) {
                struct {
                        __le32 len;
                        __le32 header_crc;
                        __le32 front_crc;
                        __le32 middle_crc;
                        __le32 data_crc;
                } __packed *sigblock = enc_buf +
                                       ceph_x_encrypt_offset(&au->session_key);

                sigblock->len = cpu_to_le32(4*sizeof(u32));
                sigblock->header_crc = msg->hdr.crc;
                sigblock->front_crc = msg->footer.front_crc;
                sigblock->middle_crc = msg->footer.middle_crc;
                sigblock->data_crc =  msg->footer.data_crc;

                ret = ceph_x_encrypt(&au->session_key, 0 /* dummy */,
                                     enc_buf, CEPHX_AU_ENC_BUF_LEN,
                                     sizeof(*sigblock));
                if (ret < 0)
                        return ret;

                *psig = *(__le64 *)(enc_buf + sizeof(u32));
        } else {
                struct {
                        __le32 header_crc;
                        __le32 front_crc;
                        __le32 front_len;
                        __le32 middle_crc;
                        __le32 middle_len;
                        __le32 data_crc;
                        __le32 data_len;
                        __le32 seq_lower_word;
                } __packed *sigblock;
                struct {
                        __le64 a, b, c, d;
                } __packed *penc = enc_buf;

                if (au->session_key.type == CEPH_CRYPTO_AES) {
                        /* no leading len, no ceph_x_encrypt_header */
                        sigblock = enc_buf;
                } else {
                        BUILD_BUG_ON(SHA256_DIGEST_SIZE + sizeof(*sigblock) >
                                     CEPHX_AU_ENC_BUF_LEN);
                        sigblock = enc_buf + SHA256_DIGEST_SIZE;
                }

                sigblock->header_crc = msg->hdr.crc;
                sigblock->front_crc = msg->footer.front_crc;
                sigblock->front_len = msg->hdr.front_len;
                sigblock->middle_crc = msg->footer.middle_crc;
                sigblock->middle_len = msg->hdr.middle_len;
                sigblock->data_crc =  msg->footer.data_crc;
                sigblock->data_len = msg->hdr.data_len;
                sigblock->seq_lower_word = *(__le32 *)&msg->hdr.seq;

                if (au->session_key.type == CEPH_CRYPTO_AES) {
                        int ciphertext_len; /* unused */

                        ret = ceph_crypt(&au->session_key, 0 /* dummy */,
                                         true, enc_buf, CEPHX_AU_ENC_BUF_LEN,
                                         sizeof(*sigblock), &ciphertext_len);
                        if (ret)
                                return ret;
                } else {
                        ceph_hmac_sha256(&au->session_key, sigblock,
                                         sizeof(*sigblock), enc_buf);
                }

                *psig = penc->a ^ penc->b ^ penc->c ^ penc->d;
        }

        return 0;
}

static int ceph_x_sign_message(struct ceph_auth_handshake *auth,
                               struct ceph_msg *msg)
{
        __le64 sig;
        int ret;

        if (ceph_test_opt(from_msgr(msg->con->msgr), NOMSGSIGN))
                return 0;

        ret = calc_signature((struct ceph_x_authorizer *)auth->authorizer,
                             msg, &sig);
        if (ret)
                return ret;

        msg->footer.sig = sig;
        msg->footer.flags |= CEPH_MSG_FOOTER_SIGNED;
        return 0;
}

static int ceph_x_check_message_signature(struct ceph_auth_handshake *auth,
                                          struct ceph_msg *msg)
{
        __le64 sig_check;
        int ret;

        if (ceph_test_opt(from_msgr(msg->con->msgr), NOMSGSIGN))
                return 0;

        ret = calc_signature((struct ceph_x_authorizer *)auth->authorizer,
                             msg, &sig_check);
        if (ret)
                return ret;
        if (sig_check == msg->footer.sig)
                return 0;
        if (msg->footer.flags & CEPH_MSG_FOOTER_SIGNED)
                dout("ceph_x_check_message_signature %p has signature %llx "
                     "expect %llx\n", msg, msg->footer.sig, sig_check);
        else
                dout("ceph_x_check_message_signature %p sender did not set "
                     "CEPH_MSG_FOOTER_SIGNED\n", msg);
        return -EBADMSG;
}

static const struct ceph_auth_client_ops ceph_x_ops = {
        .is_authenticated = ceph_x_is_authenticated,
        .should_authenticate = ceph_x_should_authenticate,
        .build_request = ceph_x_build_request,
        .handle_reply = ceph_x_handle_reply,
        .create_authorizer = ceph_x_create_authorizer,
        .update_authorizer = ceph_x_update_authorizer,
        .add_authorizer_challenge = ceph_x_add_authorizer_challenge,
        .verify_authorizer_reply = ceph_x_verify_authorizer_reply,
        .invalidate_authorizer = ceph_x_invalidate_authorizer,
        .reset =  ceph_x_reset,
        .destroy = ceph_x_destroy,
        .sign_message = ceph_x_sign_message,
        .check_message_signature = ceph_x_check_message_signature,
};


int ceph_x_init(struct ceph_auth_client *ac)
{
        struct ceph_x_info *xi;
        int ret;

        dout("ceph_x_init %p\n", ac);
        xi = kzalloc_obj(*xi, GFP_NOFS);
        if (!xi)
                return -ENOMEM;

        ret = -EINVAL;
        if (!ac->key) {
                pr_err("no secret set (for auth_x protocol)\n");
                goto err_xi;
        }

        ret = ceph_crypto_key_clone(&xi->secret, ac->key);
        if (ret < 0) {
                pr_err("cannot clone key: %d\n", ret);
                goto err_xi;
        }

        ret = ceph_crypto_key_prepare(&xi->secret, client_key_usages,
                                      ARRAY_SIZE(client_key_usages));
        if (ret) {
                pr_err("cannot prepare key: %d\n", ret);
                goto err_secret;
        }

        xi->starting = true;
        xi->ticket_handlers = RB_ROOT;

        ac->protocol = CEPH_AUTH_CEPHX;
        ac->private = xi;
        ac->ops = &ceph_x_ops;
        return 0;

err_secret:
        ceph_crypto_key_destroy(&xi->secret);
err_xi:
        kfree(xi);
        return ret;
}