auth_x.c

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

#define TEMP_TICKET_BUF_LEN 256

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 need;

    ceph_x_validate_tickets(ac, &need);
    dout("ceph_x_is_authenticated want=%d need=%d have=%d\n",
         ac->want_keys, need, xi->have_keys);
    return (ac->want_keys & xi->have_keys) == ac->want_keys;
}

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("ceph_x_should_authenticate want=%d need=%d have=%d\n",
         ac->want_keys, need, xi->have_keys);
    return need != 0;
}

static int ceph_x_encrypt_buflen(int ilen)
{
    return sizeof(struct ceph_x_encrypt_header) + ilen + 16 +
        sizeof(u32);
}

static int ceph_x_encrypt(struct ceph_crypto_key *secret,
              void *ibuf, int ilen, void *obuf, size_t olen)
{
    struct ceph_x_encrypt_header head = {
        .struct_v = 1,
        .magic = cpu_to_le64(CEPHX_ENC_MAGIC)
    };
    size_t len = olen - sizeof(u32);
    int ret;

    ret = ceph_encrypt2(secret, obuf + sizeof(u32), &len,
                &head, sizeof(head), ibuf, ilen);
    if (ret)
        return ret;
    ceph_encode_32(&obuf, len);
    return len + sizeof(u32);
}

static int ceph_x_decrypt(struct ceph_crypto_key *secret,
              void **p, void *end, void *obuf, size_t olen)
{
    struct ceph_x_encrypt_header head;
    size_t head_len = sizeof(head);
    int len, ret;

    len = ceph_decode_32(p);
    if (*p + len > end)
        return -EINVAL;

    dout("ceph_x_decrypt len %d\n", len);
    ret = ceph_decrypt2(secret, &head, &head_len, obuf, &olen,
                *p, len);
    if (ret)
        return ret;
    if (head.struct_v != 1 || le64_to_cpu(head.magic) != CEPHX_ENC_MAGIC)
        return -EPERM;
    *p += len;
    return olen;
}

/*
 * 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(sizeof(*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 ceph_x_proc_ticket_reply(struct ceph_auth_client *ac,
                    struct ceph_crypto_key *secret,
                    void *buf, void *end)
{
    struct ceph_x_info *xi = ac->private;
    int num;
    void *p = buf;
    int ret;
    char *dbuf;
    char *ticket_buf;
    u8 reply_struct_v;

    dbuf = kmalloc(TEMP_TICKET_BUF_LEN, GFP_NOFS);
    if (!dbuf)
        return -ENOMEM;

    ret = -ENOMEM;
    ticket_buf = kmalloc(TEMP_TICKET_BUF_LEN, GFP_NOFS);
    if (!ticket_buf)
        goto out_dbuf;

    ceph_decode_need(&p, end, 1 + sizeof(u32), bad);
    reply_struct_v = ceph_decode_8(&p);
    if (reply_struct_v != 1)
        goto bad;
    num = ceph_decode_32(&p);
    dout("%d tickets\n", num);
    while (num--) {
        int type;
        u8 tkt_struct_v, blob_struct_v;
        struct ceph_x_ticket_handler *th;
        void *dp, *dend;
        int dlen;
        char is_enc;
        struct timespec validity;
        struct ceph_crypto_key old_key;
        void *tp, *tpend;
        struct ceph_timespec new_validity;
        struct ceph_crypto_key new_session_key;
        struct ceph_buffer *new_ticket_blob;
        unsigned long new_expires, new_renew_after;
        u64 new_secret_id;

        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 */
        dlen = ceph_x_decrypt(secret, &p, end, dbuf,
                      TEMP_TICKET_BUF_LEN);
        if (dlen <= 0) {
            ret = dlen;
            goto out;
        }
        dout(" decrypted %d bytes\n", dlen);
        dend = dbuf + dlen;
        dp = dbuf;

        tkt_struct_v = ceph_decode_8(&dp);
        if (tkt_struct_v != 1)
            goto bad;

        memcpy(&old_key, &th->session_key, sizeof(old_key));
        ret = ceph_crypto_key_decode(&new_session_key, &dp, dend);
        if (ret)
            goto out;

        ceph_decode_copy(&dp, &new_validity, sizeof(new_validity));
        ceph_decode_timespec(&validity, &new_validity);
        new_expires = get_seconds() + validity.tv_sec;
        new_renew_after = new_expires - (validity.tv_sec / 4);
        dout(" expires=%lu renew_after=%lu\n", new_expires,
             new_renew_after);

        /* ticket blob for service */
        ceph_decode_8_safe(&p, end, is_enc, bad);
        tp = ticket_buf;
        if (is_enc) {
            /* encrypted */
            dout(" encrypted ticket\n");
            dlen = ceph_x_decrypt(&old_key, &p, end, ticket_buf,
                          TEMP_TICKET_BUF_LEN);
            if (dlen < 0) {
                ret = dlen;
                goto out;
            }
            dlen = ceph_decode_32(&tp);
        } else {
            /* unencrypted */
            ceph_decode_32_safe(&p, end, dlen, bad);
            ceph_decode_need(&p, end, dlen, bad);
            ceph_decode_copy(&p, ticket_buf, dlen);
        }
        tpend = tp + dlen;
        dout(" ticket blob is %d bytes\n", dlen);
        ceph_decode_need(&tp, tpend, 1 + sizeof(u64), bad);
        blob_struct_v = ceph_decode_8(&tp);
        new_secret_id = ceph_decode_64(&tp);
        ret = ceph_decode_buffer(&new_ticket_blob, &tp, 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->validity = new_validity;
        th->secret_id = new_secret_id;
        th->expires = new_expires;
        th->renew_after = new_renew_after;
        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;
    }

    ret = 0;
out:
    kfree(ticket_buf);
out_dbuf:
    kfree(dbuf);
    return ret;

bad:
    ret = -EINVAL;
    goto out;
}

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;
    void *p, *end;
    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);

    maxlen = sizeof(*msg_a) + sizeof(msg_b) +
        ceph_x_encrypt_buflen(ticket_blob_len);
    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)
            return -ENOMEM;
    }
    au->service = th->service;

    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));

    p = msg_a + 1;
    p += ticket_blob_len;
    end = au->buf->vec.iov_base + au->buf->vec.iov_len;

    get_random_bytes(&au->nonce, sizeof(au->nonce));
    msg_b.struct_v = 1;
    msg_b.nonce = cpu_to_le64(au->nonce);
    ret = ceph_x_encrypt(&th->session_key, &msg_b, sizeof(msg_b),
                 p, end - p);
    if (ret < 0)
        goto out_buf;
    p += ret;
    au->buf->vec.iov_len = p - au->buf->vec.iov_base;
    dout(" built authorizer nonce %llx len %d\n", au->nonce,
         (int)au->buf->vec.iov_len);
    BUG_ON(au->buf->vec.iov_len > maxlen);
    return 0;

out_buf:
    ceph_buffer_put(au->buf);
    au->buf = NULL;
    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 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 (get_seconds() >= th->renew_after)
            *pneed |= service;
        if (get_seconds() >= th->expires)
            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;
    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("build_request want %x have %x need %x\n",
         ac->want_keys, xi->have_keys, need);

    if (need & CEPH_ENTITY_TYPE_AUTH) {
        struct ceph_x_authenticate *auth = (void *)(head + 1);
        void *p = auth + 1;
        struct ceph_x_challenge_blob tmp;
        char tmp_enc[40];
        u64 *u;

        if (p > end)
            return -ERANGE;

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

        /* encrypt and hash */
        get_random_bytes(&auth->client_challenge, sizeof(u64));
        tmp.client_challenge = auth->client_challenge;
        tmp.server_challenge = cpu_to_le64(xi->server_challenge);
        ret = ceph_x_encrypt(&xi->secret, &tmp, sizeof(tmp),
                     tmp_enc, sizeof(tmp_enc));
        if (ret < 0)
            return ret;

        auth->struct_v = 1;
        auth->key = 0;
        for (u = (u64 *)tmp_enc; u + 1 <= (u64 *)(tmp_enc + 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;

        return p - buf;
    }

    if (need) {
        void *p = head + 1;
        struct ceph_x_service_ticket_request *req;

        if (p > end)
            return -ERANGE;
        head->op = cpu_to_le16(CEPHX_GET_PRINCIPAL_SESSION_KEY);

        ret = ceph_x_build_authorizer(ac, th, &xi->auth_authorizer);
        if (ret)
            return ret;
        ceph_encode_copy(&p, xi->auth_authorizer.buf->vec.iov_base,
                 xi->auth_authorizer.buf->vec.iov_len);

        req = p;
        req->keys = cpu_to_le32(need);
        p += sizeof(*req);
        return p - buf;
    }

    return 0;
}

static int ceph_x_handle_reply(struct ceph_auth_client *ac, int result,
                   void *buf, void *end)
{
    struct ceph_x_info *xi = ac->private;
    struct ceph_x_reply_header *head = buf;
    struct ceph_x_ticket_handler *th;
    int len = end - buf;
    int op;
    int ret;

    if (result)
        return result;  /* XXX hmm? */

    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;
    }

    op = le16_to_cpu(head->op);
    result = le32_to_cpu(head->result);
    dout("handle_reply op %d result %d\n", op, result);
    switch (op) {
    case CEPHX_GET_AUTH_SESSION_KEY:
        /* verify auth key */
        ret = ceph_x_proc_ticket_reply(ac, &xi->secret,
                           buf + sizeof(*head), end);
        break;

    case CEPHX_GET_PRINCIPAL_SESSION_KEY:
        th = get_ticket_handler(ac, CEPH_ENTITY_TYPE_AUTH);
        if (IS_ERR(th))
            return PTR_ERR(th);
        ret = ceph_x_proc_ticket_reply(ac, &th->session_key,
                           buf + sizeof(*head), end);
        break;

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

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

    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->reply_buf;
    auth->authorizer_reply_buf_len = sizeof (au->reply_buf);

    return 0;
}

static int ceph_x_verify_authorizer_reply(struct ceph_auth_client *ac,
                      struct ceph_authorizer *a, size_t len)
{
    struct ceph_x_authorizer *au = (void *)a;
    struct ceph_x_ticket_handler *th;
    int ret = 0;
    struct ceph_x_authorize_reply reply;
    void *p = au->reply_buf;
    void *end = p + sizeof(au->reply_buf);

    th = get_ticket_handler(ac, au->service);
    if (IS_ERR(th))
        return PTR_ERR(th);
    ret = ceph_x_decrypt(&th->session_key, &p, end, &reply, sizeof(reply));
    if (ret < 0)
        return ret;
    if (ret != sizeof(reply))
        return -EPERM;

    if (au->nonce + 1 != le64_to_cpu(reply.nonce_plus_one))
        ret = -EPERM;
    else
        ret = 0;
    dout("verify_authorizer_reply nonce %llx got %llx ret %d\n",
         au->nonce, le64_to_cpu(reply.nonce_plus_one), ret);
    return ret;
}

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

    ceph_buffer_put(au->buf);
    kfree(au);
}


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);
    }

    if (xi->auth_authorizer.buf)
        ceph_buffer_put(xi->auth_authorizer.buf);

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

static void ceph_x_invalidate_authorizer(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))
        remove_ticket_handler(ac, th);
}


static const struct ceph_auth_client_ops ceph_x_ops = {
    .name = "x",
    .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,
    .verify_authorizer_reply = ceph_x_verify_authorizer_reply,
    .destroy_authorizer = ceph_x_destroy_authorizer,
    .invalidate_authorizer = ceph_x_invalidate_authorizer,
    .reset =  ceph_x_reset,
    .destroy = ceph_x_destroy,
};


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

    dout("ceph_x_init %p\n", ac);
    ret = -ENOMEM;
    xi = kzalloc(sizeof(*xi), GFP_NOFS);
    if (!xi)
        goto out;

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

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

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

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

out_nomem:
    kfree(xi);
out:
    return ret;
}