gss_mech_switch.c

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/*
 *  linux/net/sunrpc/gss_mech_switch.c
 *
 *  Copyright (c) 2001 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  J. Bruce Fields   <[email protected]>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/sunrpc/msg_prot.h>
#include <linux/sunrpc/gss_asn1.h>
#include <linux/sunrpc/auth_gss.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/gss_err.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/gss_api.h>
#include <linux/sunrpc/clnt.h>

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY        RPCDBG_AUTH
#endif

static LIST_HEAD(registered_mechs);
static DEFINE_SPINLOCK(registered_mechs_lock);

static void
gss_mech_free(struct gss_api_mech *gm)
{
    struct pf_desc *pf;
    int i;

    for (i = 0; i < gm->gm_pf_num; i++) {
        pf = &gm->gm_pfs[i];
        kfree(pf->auth_domain_name);
        pf->auth_domain_name = NULL;
    }
}

static inline char *
make_auth_domain_name(char *name)
{
    static char *prefix = "gss/";
    char        *new;

    new = kmalloc(strlen(name) + strlen(prefix) + 1, GFP_KERNEL);
    if (new) {
        strcpy(new, prefix);
        strcat(new, name);
    }
    return new;
}

static int
gss_mech_svc_setup(struct gss_api_mech *gm)
{
    struct pf_desc *pf;
    int i, status;

    for (i = 0; i < gm->gm_pf_num; i++) {
        pf = &gm->gm_pfs[i];
        pf->auth_domain_name = make_auth_domain_name(pf->name);
        status = -ENOMEM;
        if (pf->auth_domain_name == NULL)
            goto out;
        status = svcauth_gss_register_pseudoflavor(pf->pseudoflavor,
                            pf->auth_domain_name);
        if (status)
            goto out;
    }
    return 0;
out:
    gss_mech_free(gm);
    return status;
}

int
gss_mech_register(struct gss_api_mech *gm)
{
    int status;

    status = gss_mech_svc_setup(gm);
    if (status)
        return status;
    spin_lock(&registered_mechs_lock);
    list_add(&gm->gm_list, &registered_mechs);
    spin_unlock(&registered_mechs_lock);
    dprintk("RPC:       registered gss mechanism %s\n", gm->gm_name);
    return 0;
}

EXPORT_SYMBOL_GPL(gss_mech_register);

void
gss_mech_unregister(struct gss_api_mech *gm)
{
    spin_lock(&registered_mechs_lock);
    list_del(&gm->gm_list);
    spin_unlock(&registered_mechs_lock);
    dprintk("RPC:       unregistered gss mechanism %s\n", gm->gm_name);
    gss_mech_free(gm);
}

EXPORT_SYMBOL_GPL(gss_mech_unregister);

struct gss_api_mech *
gss_mech_get(struct gss_api_mech *gm)
{
    __module_get(gm->gm_owner);
    return gm;
}

EXPORT_SYMBOL_GPL(gss_mech_get);

struct gss_api_mech *
_gss_mech_get_by_name(const char *name)
{
    struct gss_api_mech *pos, *gm = NULL;

    spin_lock(&registered_mechs_lock);
    list_for_each_entry(pos, &registered_mechs, gm_list) {
        if (0 == strcmp(name, pos->gm_name)) {
            if (try_module_get(pos->gm_owner))
                gm = pos;
            break;
        }
    }
    spin_unlock(&registered_mechs_lock);
    return gm;

}

struct gss_api_mech * gss_mech_get_by_name(const char *name)
{
    struct gss_api_mech *gm = NULL;

    gm = _gss_mech_get_by_name(name);
    if (!gm) {
        request_module("rpc-auth-gss-%s", name);
        gm = _gss_mech_get_by_name(name);
    }
    return gm;
}
EXPORT_SYMBOL_GPL(gss_mech_get_by_name);

struct gss_api_mech *
gss_mech_get_by_OID(struct xdr_netobj *obj)
{
    struct gss_api_mech *pos, *gm = NULL;

    spin_lock(&registered_mechs_lock);
    list_for_each_entry(pos, &registered_mechs, gm_list) {
        if (obj->len == pos->gm_oid.len) {
            if (0 == memcmp(obj->data, pos->gm_oid.data, obj->len)) {
                if (try_module_get(pos->gm_owner))
                    gm = pos;
                break;
            }
        }
    }
    spin_unlock(&registered_mechs_lock);
    return gm;

}

EXPORT_SYMBOL_GPL(gss_mech_get_by_OID);

static inline int
mech_supports_pseudoflavor(struct gss_api_mech *gm, u32 pseudoflavor)
{
    int i;

    for (i = 0; i < gm->gm_pf_num; i++) {
        if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
            return 1;
    }
    return 0;
}

struct gss_api_mech *_gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
{
    struct gss_api_mech *gm = NULL, *pos;

    spin_lock(&registered_mechs_lock);
    list_for_each_entry(pos, &registered_mechs, gm_list) {
        if (!mech_supports_pseudoflavor(pos, pseudoflavor)) {
            module_put(pos->gm_owner);
            continue;
        }
        if (try_module_get(pos->gm_owner))
            gm = pos;
        break;
    }
    spin_unlock(&registered_mechs_lock);
    return gm;
}

struct gss_api_mech *
gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
{
    struct gss_api_mech *gm;

    gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);

    if (!gm) {
        request_module("rpc-auth-gss-%u", pseudoflavor);
        gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
    }
    return gm;
}

EXPORT_SYMBOL_GPL(gss_mech_get_by_pseudoflavor);

int gss_mech_list_pseudoflavors(rpc_authflavor_t *array_ptr, int size)
{
    struct gss_api_mech *pos = NULL;
    int j, i = 0;

    spin_lock(&registered_mechs_lock);
    list_for_each_entry(pos, &registered_mechs, gm_list) {
        for (j = 0; j < pos->gm_pf_num; j++) {
            if (i >= size) {
                spin_unlock(&registered_mechs_lock);
                return -ENOMEM;
            }
            array_ptr[i++] = pos->gm_pfs[j].pseudoflavor;
        }
    }
    spin_unlock(&registered_mechs_lock);
    return i;
}

u32
gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 service)
{
    int i;

    for (i = 0; i < gm->gm_pf_num; i++) {
        if (gm->gm_pfs[i].service == service) {
            return gm->gm_pfs[i].pseudoflavor;
        }
    }
    return RPC_AUTH_MAXFLAVOR; /* illegal value */
}
EXPORT_SYMBOL_GPL(gss_svc_to_pseudoflavor);

u32
gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
{
    int i;

    for (i = 0; i < gm->gm_pf_num; i++) {
        if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
            return gm->gm_pfs[i].service;
    }
    return 0;
}

EXPORT_SYMBOL_GPL(gss_pseudoflavor_to_service);

char *
gss_service_to_auth_domain_name(struct gss_api_mech *gm, u32 service)
{
    int i;

    for (i = 0; i < gm->gm_pf_num; i++) {
        if (gm->gm_pfs[i].service == service)
            return gm->gm_pfs[i].auth_domain_name;
    }
    return NULL;
}

EXPORT_SYMBOL_GPL(gss_service_to_auth_domain_name);

void
gss_mech_put(struct gss_api_mech * gm)
{
    if (gm)
        module_put(gm->gm_owner);
}

EXPORT_SYMBOL_GPL(gss_mech_put);

/* The mech could probably be determined from the token instead, but it's just
 * as easy for now to pass it in. */
int
gss_import_sec_context(const void *input_token, size_t bufsize,
               struct gss_api_mech  *mech,
               struct gss_ctx       **ctx_id,
               gfp_t gfp_mask)
{
    if (!(*ctx_id = kzalloc(sizeof(**ctx_id), gfp_mask)))
        return -ENOMEM;
    (*ctx_id)->mech_type = gss_mech_get(mech);

    return mech->gm_ops
        ->gss_import_sec_context(input_token, bufsize, *ctx_id, gfp_mask);
}

/* gss_get_mic: compute a mic over message and return mic_token. */

u32
gss_get_mic(struct gss_ctx  *context_handle,
        struct xdr_buf  *message,
        struct xdr_netobj   *mic_token)
{
     return context_handle->mech_type->gm_ops
        ->gss_get_mic(context_handle,
                  message,
                  mic_token);
}

/* gss_verify_mic: check whether the provided mic_token verifies message. */

u32
gss_verify_mic(struct gss_ctx       *context_handle,
           struct xdr_buf       *message,
           struct xdr_netobj    *mic_token)
{
    return context_handle->mech_type->gm_ops
        ->gss_verify_mic(context_handle,
                 message,
                 mic_token);
}

/*
 * This function is called from both the client and server code.
 * Each makes guarantees about how much "slack" space is available
 * for the underlying function in "buf"'s head and tail while
 * performing the wrap.
 *
 * The client and server code allocate RPC_MAX_AUTH_SIZE extra
 * space in both the head and tail which is available for use by
 * the wrap function.
 *
 * Underlying functions should verify they do not use more than
 * RPC_MAX_AUTH_SIZE of extra space in either the head or tail
 * when performing the wrap.
 */
u32
gss_wrap(struct gss_ctx *ctx_id,
     int        offset,
     struct xdr_buf *buf,
     struct page    **inpages)
{
    return ctx_id->mech_type->gm_ops
        ->gss_wrap(ctx_id, offset, buf, inpages);
}

u32
gss_unwrap(struct gss_ctx   *ctx_id,
       int          offset,
       struct xdr_buf   *buf)
{
    return ctx_id->mech_type->gm_ops
        ->gss_unwrap(ctx_id, offset, buf);
}


/* gss_delete_sec_context: free all resources associated with context_handle.
 * Note this differs from the RFC 2744-specified prototype in that we don't
 * bother returning an output token, since it would never be used anyway. */

u32
gss_delete_sec_context(struct gss_ctx   **context_handle)
{
    dprintk("RPC:       gss_delete_sec_context deleting %p\n",
            *context_handle);

    if (!*context_handle)
        return GSS_S_NO_CONTEXT;
    if ((*context_handle)->internal_ctx_id)
        (*context_handle)->mech_type->gm_ops
            ->gss_delete_sec_context((*context_handle)
                            ->internal_ctx_id);
    gss_mech_put((*context_handle)->mech_type);
    kfree(*context_handle);
    *context_handle=NULL;
    return GSS_S_COMPLETE;
}