diff options
Diffstat (limited to 'net/sunrpc/auth_gss/svcauth_gss.c')
| -rw-r--r-- | net/sunrpc/auth_gss/svcauth_gss.c | 1523 |
1 files changed, 1523 insertions, 0 deletions
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c new file mode 100644 index 00000000..1600cfb1 --- /dev/null +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -0,0 +1,1523 @@ +/* + * Neil Brown <neilb@cse.unsw.edu.au> + * J. Bruce Fields <bfields@umich.edu> + * Andy Adamson <andros@umich.edu> + * Dug Song <dugsong@monkey.org> + * + * RPCSEC_GSS server authentication. + * This implements RPCSEC_GSS as defined in rfc2203 (rpcsec_gss) and rfc2078 + * (gssapi) + * + * The RPCSEC_GSS involves three stages: + * 1/ context creation + * 2/ data exchange + * 3/ context destruction + * + * Context creation is handled largely by upcalls to user-space. + * In particular, GSS_Accept_sec_context is handled by an upcall + * Data exchange is handled entirely within the kernel + * In particular, GSS_GetMIC, GSS_VerifyMIC, GSS_Seal, GSS_Unseal are in-kernel. + * Context destruction is handled in-kernel + * GSS_Delete_sec_context is in-kernel + * + * Context creation is initiated by a RPCSEC_GSS_INIT request arriving. + * The context handle and gss_token are used as a key into the rpcsec_init cache. + * The content of this cache includes some of the outputs of GSS_Accept_sec_context, + * being major_status, minor_status, context_handle, reply_token. + * These are sent back to the client. + * Sequence window management is handled by the kernel. The window size if currently + * a compile time constant. + * + * When user-space is happy that a context is established, it places an entry + * in the rpcsec_context cache. The key for this cache is the context_handle. + * The content includes: + * uid/gidlist - for determining access rights + * mechanism type + * mechanism specific information, such as a key + * + */ + +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/module.h> +#include <linux/pagemap.h> + +#include <linux/sunrpc/auth_gss.h> +#include <linux/sunrpc/gss_err.h> +#include <linux/sunrpc/svcauth.h> +#include <linux/sunrpc/svcauth_gss.h> +#include <linux/sunrpc/cache.h> + +#include "../netns.h" + +#ifdef RPC_DEBUG +# define RPCDBG_FACILITY RPCDBG_AUTH +#endif + +/* The rpcsec_init cache is used for mapping RPCSEC_GSS_{,CONT_}INIT requests + * into replies. + * + * Key is context handle (\x if empty) and gss_token. + * Content is major_status minor_status (integers) context_handle, reply_token. + * + */ + +static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b) +{ + return a->len == b->len && 0 == memcmp(a->data, b->data, a->len); +} + +#define RSI_HASHBITS 6 +#define RSI_HASHMAX (1<<RSI_HASHBITS) + +struct rsi { + struct cache_head h; + struct xdr_netobj in_handle, in_token; + struct xdr_netobj out_handle, out_token; + int major_status, minor_status; +}; + +static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old); +static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item); + +static void rsi_free(struct rsi *rsii) +{ + kfree(rsii->in_handle.data); + kfree(rsii->in_token.data); + kfree(rsii->out_handle.data); + kfree(rsii->out_token.data); +} + +static void rsi_put(struct kref *ref) +{ + struct rsi *rsii = container_of(ref, struct rsi, h.ref); + rsi_free(rsii); + kfree(rsii); +} + +static inline int rsi_hash(struct rsi *item) +{ + return hash_mem(item->in_handle.data, item->in_handle.len, RSI_HASHBITS) + ^ hash_mem(item->in_token.data, item->in_token.len, RSI_HASHBITS); +} + +static int rsi_match(struct cache_head *a, struct cache_head *b) +{ + struct rsi *item = container_of(a, struct rsi, h); + struct rsi *tmp = container_of(b, struct rsi, h); + return netobj_equal(&item->in_handle, &tmp->in_handle) && + netobj_equal(&item->in_token, &tmp->in_token); +} + +static int dup_to_netobj(struct xdr_netobj *dst, char *src, int len) +{ + dst->len = len; + dst->data = (len ? kmemdup(src, len, GFP_KERNEL) : NULL); + if (len && !dst->data) + return -ENOMEM; + return 0; +} + +static inline int dup_netobj(struct xdr_netobj *dst, struct xdr_netobj *src) +{ + return dup_to_netobj(dst, src->data, src->len); +} + +static void rsi_init(struct cache_head *cnew, struct cache_head *citem) +{ + struct rsi *new = container_of(cnew, struct rsi, h); + struct rsi *item = container_of(citem, struct rsi, h); + + new->out_handle.data = NULL; + new->out_handle.len = 0; + new->out_token.data = NULL; + new->out_token.len = 0; + new->in_handle.len = item->in_handle.len; + item->in_handle.len = 0; + new->in_token.len = item->in_token.len; + item->in_token.len = 0; + new->in_handle.data = item->in_handle.data; + item->in_handle.data = NULL; + new->in_token.data = item->in_token.data; + item->in_token.data = NULL; +} + +static void update_rsi(struct cache_head *cnew, struct cache_head *citem) +{ + struct rsi *new = container_of(cnew, struct rsi, h); + struct rsi *item = container_of(citem, struct rsi, h); + + BUG_ON(new->out_handle.data || new->out_token.data); + new->out_handle.len = item->out_handle.len; + item->out_handle.len = 0; + new->out_token.len = item->out_token.len; + item->out_token.len = 0; + new->out_handle.data = item->out_handle.data; + item->out_handle.data = NULL; + new->out_token.data = item->out_token.data; + item->out_token.data = NULL; + + new->major_status = item->major_status; + new->minor_status = item->minor_status; +} + +static struct cache_head *rsi_alloc(void) +{ + struct rsi *rsii = kmalloc(sizeof(*rsii), GFP_KERNEL); + if (rsii) + return &rsii->h; + else + return NULL; +} + +static void rsi_request(struct cache_detail *cd, + struct cache_head *h, + char **bpp, int *blen) +{ + struct rsi *rsii = container_of(h, struct rsi, h); + + qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len); + qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len); + (*bpp)[-1] = '\n'; +} + +static int rsi_upcall(struct cache_detail *cd, struct cache_head *h) +{ + return sunrpc_cache_pipe_upcall(cd, h, rsi_request); +} + + +static int rsi_parse(struct cache_detail *cd, + char *mesg, int mlen) +{ + /* context token expiry major minor context token */ + char *buf = mesg; + char *ep; + int len; + struct rsi rsii, *rsip = NULL; + time_t expiry; + int status = -EINVAL; + + memset(&rsii, 0, sizeof(rsii)); + /* handle */ + len = qword_get(&mesg, buf, mlen); + if (len < 0) + goto out; + status = -ENOMEM; + if (dup_to_netobj(&rsii.in_handle, buf, len)) + goto out; + + /* token */ + len = qword_get(&mesg, buf, mlen); + status = -EINVAL; + if (len < 0) + goto out; + status = -ENOMEM; + if (dup_to_netobj(&rsii.in_token, buf, len)) + goto out; + + rsip = rsi_lookup(cd, &rsii); + if (!rsip) + goto out; + + rsii.h.flags = 0; + /* expiry */ + expiry = get_expiry(&mesg); + status = -EINVAL; + if (expiry == 0) + goto out; + + /* major/minor */ + len = qword_get(&mesg, buf, mlen); + if (len <= 0) + goto out; + rsii.major_status = simple_strtoul(buf, &ep, 10); + if (*ep) + goto out; + len = qword_get(&mesg, buf, mlen); + if (len <= 0) + goto out; + rsii.minor_status = simple_strtoul(buf, &ep, 10); + if (*ep) + goto out; + + /* out_handle */ + len = qword_get(&mesg, buf, mlen); + if (len < 0) + goto out; + status = -ENOMEM; + if (dup_to_netobj(&rsii.out_handle, buf, len)) + goto out; + + /* out_token */ + len = qword_get(&mesg, buf, mlen); + status = -EINVAL; + if (len < 0) + goto out; + status = -ENOMEM; + if (dup_to_netobj(&rsii.out_token, buf, len)) + goto out; + rsii.h.expiry_time = expiry; + rsip = rsi_update(cd, &rsii, rsip); + status = 0; +out: + rsi_free(&rsii); + if (rsip) + cache_put(&rsip->h, cd); + else + status = -ENOMEM; + return status; +} + +static struct cache_detail rsi_cache_template = { + .owner = THIS_MODULE, + .hash_size = RSI_HASHMAX, + .name = "auth.rpcsec.init", + .cache_put = rsi_put, + .cache_upcall = rsi_upcall, + .cache_parse = rsi_parse, + .match = rsi_match, + .init = rsi_init, + .update = update_rsi, + .alloc = rsi_alloc, +}; + +static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item) +{ + struct cache_head *ch; + int hash = rsi_hash(item); + + ch = sunrpc_cache_lookup(cd, &item->h, hash); + if (ch) + return container_of(ch, struct rsi, h); + else + return NULL; +} + +static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old) +{ + struct cache_head *ch; + int hash = rsi_hash(new); + + ch = sunrpc_cache_update(cd, &new->h, + &old->h, hash); + if (ch) + return container_of(ch, struct rsi, h); + else + return NULL; +} + + +/* + * The rpcsec_context cache is used to store a context that is + * used in data exchange. + * The key is a context handle. The content is: + * uid, gidlist, mechanism, service-set, mech-specific-data + */ + +#define RSC_HASHBITS 10 +#define RSC_HASHMAX (1<<RSC_HASHBITS) + +#define GSS_SEQ_WIN 128 + +struct gss_svc_seq_data { + /* highest seq number seen so far: */ + int sd_max; + /* for i such that sd_max-GSS_SEQ_WIN < i <= sd_max, the i-th bit of + * sd_win is nonzero iff sequence number i has been seen already: */ + unsigned long sd_win[GSS_SEQ_WIN/BITS_PER_LONG]; + spinlock_t sd_lock; +}; + +struct rsc { + struct cache_head h; + struct xdr_netobj handle; + struct svc_cred cred; + struct gss_svc_seq_data seqdata; + struct gss_ctx *mechctx; + char *client_name; +}; + +static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old); +static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item); + +static void rsc_free(struct rsc *rsci) +{ + kfree(rsci->handle.data); + if (rsci->mechctx) + gss_delete_sec_context(&rsci->mechctx); + if (rsci->cred.cr_group_info) + put_group_info(rsci->cred.cr_group_info); + kfree(rsci->client_name); +} + +static void rsc_put(struct kref *ref) +{ + struct rsc *rsci = container_of(ref, struct rsc, h.ref); + + rsc_free(rsci); + kfree(rsci); +} + +static inline int +rsc_hash(struct rsc *rsci) +{ + return hash_mem(rsci->handle.data, rsci->handle.len, RSC_HASHBITS); +} + +static int +rsc_match(struct cache_head *a, struct cache_head *b) +{ + struct rsc *new = container_of(a, struct rsc, h); + struct rsc *tmp = container_of(b, struct rsc, h); + + return netobj_equal(&new->handle, &tmp->handle); +} + +static void +rsc_init(struct cache_head *cnew, struct cache_head *ctmp) +{ + struct rsc *new = container_of(cnew, struct rsc, h); + struct rsc *tmp = container_of(ctmp, struct rsc, h); + + new->handle.len = tmp->handle.len; + tmp->handle.len = 0; + new->handle.data = tmp->handle.data; + tmp->handle.data = NULL; + new->mechctx = NULL; + new->cred.cr_group_info = NULL; + new->client_name = NULL; +} + +static void +update_rsc(struct cache_head *cnew, struct cache_head *ctmp) +{ + struct rsc *new = container_of(cnew, struct rsc, h); + struct rsc *tmp = container_of(ctmp, struct rsc, h); + + new->mechctx = tmp->mechctx; + tmp->mechctx = NULL; + memset(&new->seqdata, 0, sizeof(new->seqdata)); + spin_lock_init(&new->seqdata.sd_lock); + new->cred = tmp->cred; + tmp->cred.cr_group_info = NULL; + new->client_name = tmp->client_name; + tmp->client_name = NULL; +} + +static struct cache_head * +rsc_alloc(void) +{ + struct rsc *rsci = kmalloc(sizeof(*rsci), GFP_KERNEL); + if (rsci) + return &rsci->h; + else + return NULL; +} + +static int rsc_parse(struct cache_detail *cd, + char *mesg, int mlen) +{ + /* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */ + char *buf = mesg; + int len, rv; + struct rsc rsci, *rscp = NULL; + time_t expiry; + int status = -EINVAL; + struct gss_api_mech *gm = NULL; + + memset(&rsci, 0, sizeof(rsci)); + /* context handle */ + len = qword_get(&mesg, buf, mlen); + if (len < 0) goto out; + status = -ENOMEM; + if (dup_to_netobj(&rsci.handle, buf, len)) + goto out; + + rsci.h.flags = 0; + /* expiry */ + expiry = get_expiry(&mesg); + status = -EINVAL; + if (expiry == 0) + goto out; + + rscp = rsc_lookup(cd, &rsci); + if (!rscp) + goto out; + + /* uid, or NEGATIVE */ + rv = get_int(&mesg, &rsci.cred.cr_uid); + if (rv == -EINVAL) + goto out; + if (rv == -ENOENT) + set_bit(CACHE_NEGATIVE, &rsci.h.flags); + else { + int N, i; + + /* gid */ + if (get_int(&mesg, &rsci.cred.cr_gid)) + goto out; + + /* number of additional gid's */ + if (get_int(&mesg, &N)) + goto out; + status = -ENOMEM; + rsci.cred.cr_group_info = groups_alloc(N); + if (rsci.cred.cr_group_info == NULL) + goto out; + + /* gid's */ + status = -EINVAL; + for (i=0; i<N; i++) { + gid_t gid; + if (get_int(&mesg, &gid)) + goto out; + GROUP_AT(rsci.cred.cr_group_info, i) = gid; + } + + /* mech name */ + len = qword_get(&mesg, buf, mlen); + if (len < 0) + goto out; + gm = gss_mech_get_by_name(buf); + status = -EOPNOTSUPP; + if (!gm) + goto out; + + status = -EINVAL; + /* mech-specific data: */ + len = qword_get(&mesg, buf, mlen); + if (len < 0) + goto out; + status = gss_import_sec_context(buf, len, gm, &rsci.mechctx, GFP_KERNEL); + if (status) + goto out; + + /* get client name */ + len = qword_get(&mesg, buf, mlen); + if (len > 0) { + rsci.client_name = kstrdup(buf, GFP_KERNEL); + if (!rsci.client_name) + goto out; + } + + } + rsci.h.expiry_time = expiry; + rscp = rsc_update(cd, &rsci, rscp); + status = 0; +out: + gss_mech_put(gm); + rsc_free(&rsci); + if (rscp) + cache_put(&rscp->h, cd); + else + status = -ENOMEM; + return status; +} + +static struct cache_detail rsc_cache_template = { + .owner = THIS_MODULE, + .hash_size = RSC_HASHMAX, + .name = "auth.rpcsec.context", + .cache_put = rsc_put, + .cache_parse = rsc_parse, + .match = rsc_match, + .init = rsc_init, + .update = update_rsc, + .alloc = rsc_alloc, +}; + +static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item) +{ + struct cache_head *ch; + int hash = rsc_hash(item); + + ch = sunrpc_cache_lookup(cd, &item->h, hash); + if (ch) + return container_of(ch, struct rsc, h); + else + return NULL; +} + +static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old) +{ + struct cache_head *ch; + int hash = rsc_hash(new); + + ch = sunrpc_cache_update(cd, &new->h, + &old->h, hash); + if (ch) + return container_of(ch, struct rsc, h); + else + return NULL; +} + + +static struct rsc * +gss_svc_searchbyctx(struct cache_detail *cd, struct xdr_netobj *handle) +{ + struct rsc rsci; + struct rsc *found; + + memset(&rsci, 0, sizeof(rsci)); + if (dup_to_netobj(&rsci.handle, handle->data, handle->len)) + return NULL; + found = rsc_lookup(cd, &rsci); + rsc_free(&rsci); + if (!found) + return NULL; + if (cache_check(cd, &found->h, NULL)) + return NULL; + return found; +} + +/* Implements sequence number algorithm as specified in RFC 2203. */ +static int +gss_check_seq_num(struct rsc *rsci, int seq_num) +{ + struct gss_svc_seq_data *sd = &rsci->seqdata; + + spin_lock(&sd->sd_lock); + if (seq_num > sd->sd_max) { + if (seq_num >= sd->sd_max + GSS_SEQ_WIN) { + memset(sd->sd_win,0,sizeof(sd->sd_win)); + sd->sd_max = seq_num; + } else while (sd->sd_max < seq_num) { + sd->sd_max++; + __clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win); + } + __set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win); + goto ok; + } else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) { + goto drop; + } + /* sd_max - GSS_SEQ_WIN < seq_num <= sd_max */ + if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win)) + goto drop; +ok: + spin_unlock(&sd->sd_lock); + return 1; +drop: + spin_unlock(&sd->sd_lock); + return 0; +} + +static inline u32 round_up_to_quad(u32 i) +{ + return (i + 3 ) & ~3; +} + +static inline int +svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o) +{ + int l; + + if (argv->iov_len < 4) + return -1; + o->len = svc_getnl(argv); + l = round_up_to_quad(o->len); + if (argv->iov_len < l) + return -1; + o->data = argv->iov_base; + argv->iov_base += l; + argv->iov_len -= l; + return 0; +} + +static inline int +svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o) +{ + u8 *p; + + if (resv->iov_len + 4 > PAGE_SIZE) + return -1; + svc_putnl(resv, o->len); + p = resv->iov_base + resv->iov_len; + resv->iov_len += round_up_to_quad(o->len); + if (resv->iov_len > PAGE_SIZE) + return -1; + memcpy(p, o->data, o->len); + memset(p + o->len, 0, round_up_to_quad(o->len) - o->len); + return 0; +} + +/* + * Verify the checksum on the header and return SVC_OK on success. + * Otherwise, return SVC_DROP (in the case of a bad sequence number) + * or return SVC_DENIED and indicate error in authp. + */ +static int +gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci, + __be32 *rpcstart, struct rpc_gss_wire_cred *gc, __be32 *authp) +{ + struct gss_ctx *ctx_id = rsci->mechctx; + struct xdr_buf rpchdr; + struct xdr_netobj checksum; + u32 flavor = 0; + struct kvec *argv = &rqstp->rq_arg.head[0]; + struct kvec iov; + + /* data to compute the checksum over: */ + iov.iov_base = rpcstart; + iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart; + xdr_buf_from_iov(&iov, &rpchdr); + + *authp = rpc_autherr_badverf; + if (argv->iov_len < 4) + return SVC_DENIED; + flavor = svc_getnl(argv); + if (flavor != RPC_AUTH_GSS) + return SVC_DENIED; + if (svc_safe_getnetobj(argv, &checksum)) + return SVC_DENIED; + + if (rqstp->rq_deferred) /* skip verification of revisited request */ + return SVC_OK; + if (gss_verify_mic(ctx_id, &rpchdr, &checksum) != GSS_S_COMPLETE) { + *authp = rpcsec_gsserr_credproblem; + return SVC_DENIED; + } + + if (gc->gc_seq > MAXSEQ) { + dprintk("RPC: svcauth_gss: discarding request with " + "large sequence number %d\n", gc->gc_seq); + *authp = rpcsec_gsserr_ctxproblem; + return SVC_DENIED; + } + if (!gss_check_seq_num(rsci, gc->gc_seq)) { + dprintk("RPC: svcauth_gss: discarding request with " + "old sequence number %d\n", gc->gc_seq); + return SVC_DROP; + } + return SVC_OK; +} + +static int +gss_write_null_verf(struct svc_rqst *rqstp) +{ + __be32 *p; + + svc_putnl(rqstp->rq_res.head, RPC_AUTH_NULL); + p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len; + /* don't really need to check if head->iov_len > PAGE_SIZE ... */ + *p++ = 0; + if (!xdr_ressize_check(rqstp, p)) + return -1; + return 0; +} + +static int +gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq) +{ + __be32 xdr_seq; + u32 maj_stat; + struct xdr_buf verf_data; + struct xdr_netobj mic; + __be32 *p; + struct kvec iov; + + svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS); + xdr_seq = htonl(seq); + + iov.iov_base = &xdr_seq; + iov.iov_len = sizeof(xdr_seq); + xdr_buf_from_iov(&iov, &verf_data); + p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len; + mic.data = (u8 *)(p + 1); + maj_stat = gss_get_mic(ctx_id, &verf_data, &mic); + if (maj_stat != GSS_S_COMPLETE) + return -1; + *p++ = htonl(mic.len); + memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len); + p += XDR_QUADLEN(mic.len); + if (!xdr_ressize_check(rqstp, p)) + return -1; + return 0; +} + +struct gss_domain { + struct auth_domain h; + u32 pseudoflavor; +}; + +static struct auth_domain * +find_gss_auth_domain(struct gss_ctx *ctx, u32 svc) +{ + char *name; + + name = gss_service_to_auth_domain_name(ctx->mech_type, svc); + if (!name) + return NULL; + return auth_domain_find(name); +} + +static struct auth_ops svcauthops_gss; + +u32 svcauth_gss_flavor(struct auth_domain *dom) +{ + struct gss_domain *gd = container_of(dom, struct gss_domain, h); + + return gd->pseudoflavor; +} + +EXPORT_SYMBOL_GPL(svcauth_gss_flavor); + +int +svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name) +{ + struct gss_domain *new; + struct auth_domain *test; + int stat = -ENOMEM; + + new = kmalloc(sizeof(*new), GFP_KERNEL); + if (!new) + goto out; + kref_init(&new->h.ref); + new->h.name = kstrdup(name, GFP_KERNEL); + if (!new->h.name) + goto out_free_dom; + new->h.flavour = &svcauthops_gss; + new->pseudoflavor = pseudoflavor; + + stat = 0; + test = auth_domain_lookup(name, &new->h); + if (test != &new->h) { /* Duplicate registration */ + auth_domain_put(test); + kfree(new->h.name); + goto out_free_dom; + } + return 0; + +out_free_dom: + kfree(new); +out: + return stat; +} + +EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor); + +static inline int +read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj) +{ + __be32 raw; + int status; + + status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj)); + if (status) + return status; + *obj = ntohl(raw); + return 0; +} + +/* It would be nice if this bit of code could be shared with the client. + * Obstacles: + * The client shouldn't malloc(), would have to pass in own memory. + * The server uses base of head iovec as read pointer, while the + * client uses separate pointer. */ +static int +unwrap_integ_data(struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx) +{ + int stat = -EINVAL; + u32 integ_len, maj_stat; + struct xdr_netobj mic; + struct xdr_buf integ_buf; + + integ_len = svc_getnl(&buf->head[0]); + if (integ_len & 3) + return stat; + if (integ_len > buf->len) + return stat; + if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len)) + BUG(); + /* copy out mic... */ + if (read_u32_from_xdr_buf(buf, integ_len, &mic.len)) + BUG(); + if (mic.len > RPC_MAX_AUTH_SIZE) + return stat; + mic.data = kmalloc(mic.len, GFP_KERNEL); + if (!mic.data) + return stat; + if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len)) + goto out; + maj_stat = gss_verify_mic(ctx, &integ_buf, &mic); + if (maj_stat != GSS_S_COMPLETE) + goto out; + if (svc_getnl(&buf->head[0]) != seq) + goto out; + stat = 0; +out: + kfree(mic.data); + return stat; +} + +static inline int +total_buf_len(struct xdr_buf *buf) +{ + return buf->head[0].iov_len + buf->page_len + buf->tail[0].iov_len; +} + +static void +fix_priv_head(struct xdr_buf *buf, int pad) +{ + if (buf->page_len == 0) { + /* We need to adjust head and buf->len in tandem in this + * case to make svc_defer() work--it finds the original + * buffer start using buf->len - buf->head[0].iov_len. */ + buf->head[0].iov_len -= pad; + } +} + +static int +unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx) +{ + u32 priv_len, maj_stat; + int pad, saved_len, remaining_len, offset; + + rqstp->rq_splice_ok = 0; + + priv_len = svc_getnl(&buf->head[0]); + if (rqstp->rq_deferred) { + /* Already decrypted last time through! The sequence number + * check at out_seq is unnecessary but harmless: */ + goto out_seq; + } + /* buf->len is the number of bytes from the original start of the + * request to the end, where head[0].iov_len is just the bytes + * not yet read from the head, so these two values are different: */ + remaining_len = total_buf_len(buf); + if (priv_len > remaining_len) + return -EINVAL; + pad = remaining_len - priv_len; + buf->len -= pad; + fix_priv_head(buf, pad); + + /* Maybe it would be better to give gss_unwrap a length parameter: */ + saved_len = buf->len; + buf->len = priv_len; + maj_stat = gss_unwrap(ctx, 0, buf); + pad = priv_len - buf->len; + buf->len = saved_len; + buf->len -= pad; + /* The upper layers assume the buffer is aligned on 4-byte boundaries. + * In the krb5p case, at least, the data ends up offset, so we need to + * move it around. */ + /* XXX: This is very inefficient. It would be better to either do + * this while we encrypt, or maybe in the receive code, if we can peak + * ahead and work out the service and mechanism there. */ + offset = buf->head[0].iov_len % 4; + if (offset) { + buf->buflen = RPCSVC_MAXPAYLOAD; + xdr_shift_buf(buf, offset); + fix_priv_head(buf, pad); + } + if (maj_stat != GSS_S_COMPLETE) + return -EINVAL; +out_seq: + if (svc_getnl(&buf->head[0]) != seq) + return -EINVAL; + return 0; +} + +struct gss_svc_data { + /* decoded gss client cred: */ + struct rpc_gss_wire_cred clcred; + /* save a pointer to the beginning of the encoded verifier, + * for use in encryption/checksumming in svcauth_gss_release: */ + __be32 *verf_start; + struct rsc *rsci; +}; + +char *svc_gss_principal(struct svc_rqst *rqstp) +{ + struct gss_svc_data *gd = (struct gss_svc_data *)rqstp->rq_auth_data; + + if (gd && gd->rsci) + return gd->rsci->client_name; + return NULL; +} +EXPORT_SYMBOL_GPL(svc_gss_principal); + +static int +svcauth_gss_set_client(struct svc_rqst *rqstp) +{ + struct gss_svc_data *svcdata = rqstp->rq_auth_data; + struct rsc *rsci = svcdata->rsci; + struct rpc_gss_wire_cred *gc = &svcdata->clcred; + int stat; + + /* + * A gss export can be specified either by: + * export *(sec=krb5,rw) + * or by + * export gss/krb5(rw) + * The latter is deprecated; but for backwards compatibility reasons + * the nfsd code will still fall back on trying it if the former + * doesn't work; so we try to make both available to nfsd, below. + */ + rqstp->rq_gssclient = find_gss_auth_domain(rsci->mechctx, gc->gc_svc); + if (rqstp->rq_gssclient == NULL) + return SVC_DENIED; + stat = svcauth_unix_set_client(rqstp); + if (stat == SVC_DROP || stat == SVC_CLOSE) + return stat; + return SVC_OK; +} + +static inline int +gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp, struct rsi *rsip) +{ + struct rsc *rsci; + int rc; + + if (rsip->major_status != GSS_S_COMPLETE) + return gss_write_null_verf(rqstp); + rsci = gss_svc_searchbyctx(cd, &rsip->out_handle); + if (rsci == NULL) { + rsip->major_status = GSS_S_NO_CONTEXT; + return gss_write_null_verf(rqstp); + } + rc = gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN); + cache_put(&rsci->h, cd); + return rc; +} + +/* + * Having read the cred already and found we're in the context + * initiation case, read the verifier and initiate (or check the results + * of) upcalls to userspace for help with context initiation. If + * the upcall results are available, write the verifier and result. + * Otherwise, drop the request pending an answer to the upcall. + */ +static int svcauth_gss_handle_init(struct svc_rqst *rqstp, + struct rpc_gss_wire_cred *gc, __be32 *authp) +{ + struct kvec *argv = &rqstp->rq_arg.head[0]; + struct kvec *resv = &rqstp->rq_res.head[0]; + struct xdr_netobj tmpobj; + struct rsi *rsip, rsikey; + int ret; + struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id); + + /* Read the verifier; should be NULL: */ + *authp = rpc_autherr_badverf; + if (argv->iov_len < 2 * 4) + return SVC_DENIED; + if (svc_getnl(argv) != RPC_AUTH_NULL) + return SVC_DENIED; + if (svc_getnl(argv) != 0) + return SVC_DENIED; + + /* Martial context handle and token for upcall: */ + *authp = rpc_autherr_badcred; + if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0) + return SVC_DENIED; + memset(&rsikey, 0, sizeof(rsikey)); + if (dup_netobj(&rsikey.in_handle, &gc->gc_ctx)) + return SVC_CLOSE; + *authp = rpc_autherr_badverf; + if (svc_safe_getnetobj(argv, &tmpobj)) { + kfree(rsikey.in_handle.data); + return SVC_DENIED; + } + if (dup_netobj(&rsikey.in_token, &tmpobj)) { + kfree(rsikey.in_handle.data); + return SVC_CLOSE; + } + + /* Perform upcall, or find upcall result: */ + rsip = rsi_lookup(sn->rsi_cache, &rsikey); + rsi_free(&rsikey); + if (!rsip) + return SVC_CLOSE; + if (cache_check(sn->rsi_cache, &rsip->h, &rqstp->rq_chandle) < 0) + /* No upcall result: */ + return SVC_CLOSE; + + ret = SVC_CLOSE; + /* Got an answer to the upcall; use it: */ + if (gss_write_init_verf(sn->rsc_cache, rqstp, rsip)) + goto out; + if (resv->iov_len + 4 > PAGE_SIZE) + goto out; + svc_putnl(resv, RPC_SUCCESS); + if (svc_safe_putnetobj(resv, &rsip->out_handle)) + goto out; + if (resv->iov_len + 3 * 4 > PAGE_SIZE) + goto out; + svc_putnl(resv, rsip->major_status); + svc_putnl(resv, rsip->minor_status); + svc_putnl(resv, GSS_SEQ_WIN); + if (svc_safe_putnetobj(resv, &rsip->out_token)) + goto out; + + ret = SVC_COMPLETE; +out: + cache_put(&rsip->h, sn->rsi_cache); + return ret; +} + +/* + * Accept an rpcsec packet. + * If context establishment, punt to user space + * If data exchange, verify/decrypt + * If context destruction, handle here + * In the context establishment and destruction case we encode + * response here and return SVC_COMPLETE. + */ +static int +svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp) +{ + struct kvec *argv = &rqstp->rq_arg.head[0]; + struct kvec *resv = &rqstp->rq_res.head[0]; + u32 crlen; + struct gss_svc_data *svcdata = rqstp->rq_auth_data; + struct rpc_gss_wire_cred *gc; + struct rsc *rsci = NULL; + __be32 *rpcstart; + __be32 *reject_stat = resv->iov_base + resv->iov_len; + int ret; + struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id); + + dprintk("RPC: svcauth_gss: argv->iov_len = %zd\n", + argv->iov_len); + + *authp = rpc_autherr_badcred; + if (!svcdata) + svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL); + if (!svcdata) + goto auth_err; + rqstp->rq_auth_data = svcdata; + svcdata->verf_start = NULL; + svcdata->rsci = NULL; + gc = &svcdata->clcred; + + /* start of rpc packet is 7 u32's back from here: + * xid direction rpcversion prog vers proc flavour + */ + rpcstart = argv->iov_base; + rpcstart -= 7; + + /* credential is: + * version(==1), proc(0,1,2,3), seq, service (1,2,3), handle + * at least 5 u32s, and is preceded by length, so that makes 6. + */ + + if (argv->iov_len < 5 * 4) + goto auth_err; + crlen = svc_getnl(argv); + if (svc_getnl(argv) != RPC_GSS_VERSION) + goto auth_err; + gc->gc_proc = svc_getnl(argv); + gc->gc_seq = svc_getnl(argv); + gc->gc_svc = svc_getnl(argv); + if (svc_safe_getnetobj(argv, &gc->gc_ctx)) + goto auth_err; + if (crlen != round_up_to_quad(gc->gc_ctx.len) + 5 * 4) + goto auth_err; + + if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0)) + goto auth_err; + + *authp = rpc_autherr_badverf; + switch (gc->gc_proc) { + case RPC_GSS_PROC_INIT: + case RPC_GSS_PROC_CONTINUE_INIT: + return svcauth_gss_handle_init(rqstp, gc, authp); + case RPC_GSS_PROC_DATA: + case RPC_GSS_PROC_DESTROY: + /* Look up the context, and check the verifier: */ + *authp = rpcsec_gsserr_credproblem; + rsci = gss_svc_searchbyctx(sn->rsc_cache, &gc->gc_ctx); + if (!rsci) + goto auth_err; + switch (gss_verify_header(rqstp, rsci, rpcstart, gc, authp)) { + case SVC_OK: + break; + case SVC_DENIED: + goto auth_err; + case SVC_DROP: + goto drop; + } + break; + default: + *authp = rpc_autherr_rejectedcred; + goto auth_err; + } + + /* now act upon the command: */ + switch (gc->gc_proc) { + case RPC_GSS_PROC_DESTROY: + if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq)) + goto auth_err; + rsci->h.expiry_time = get_seconds(); + set_bit(CACHE_NEGATIVE, &rsci->h.flags); + if (resv->iov_len + 4 > PAGE_SIZE) + goto drop; + svc_putnl(resv, RPC_SUCCESS); + goto complete; + case RPC_GSS_PROC_DATA: + *authp = rpcsec_gsserr_ctxproblem; + svcdata->verf_start = resv->iov_base + resv->iov_len; + if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq)) + goto auth_err; + rqstp->rq_cred = rsci->cred; + get_group_info(rsci->cred.cr_group_info); + *authp = rpc_autherr_badcred; + switch (gc->gc_svc) { + case RPC_GSS_SVC_NONE: + break; + case RPC_GSS_SVC_INTEGRITY: + /* placeholders for length and seq. number: */ + svc_putnl(resv, 0); + svc_putnl(resv, 0); + if (unwrap_integ_data(&rqstp->rq_arg, + gc->gc_seq, rsci->mechctx)) + goto garbage_args; + break; + case RPC_GSS_SVC_PRIVACY: + /* placeholders for length and seq. number: */ + svc_putnl(resv, 0); + svc_putnl(resv, 0); + if (unwrap_priv_data(rqstp, &rqstp->rq_arg, + gc->gc_seq, rsci->mechctx)) + goto garbage_args; + break; + default: + goto auth_err; + } + svcdata->rsci = rsci; + cache_get(&rsci->h); + rqstp->rq_flavor = gss_svc_to_pseudoflavor( + rsci->mechctx->mech_type, gc->gc_svc); + ret = SVC_OK; + goto out; + } +garbage_args: + ret = SVC_GARBAGE; + goto out; +auth_err: + /* Restore write pointer to its original value: */ + xdr_ressize_check(rqstp, reject_stat); + ret = SVC_DENIED; + goto out; +complete: + ret = SVC_COMPLETE; + goto out; +drop: + ret = SVC_DROP; +out: + if (rsci) + cache_put(&rsci->h, sn->rsc_cache); + return ret; +} + +static __be32 * +svcauth_gss_prepare_to_wrap(struct xdr_buf *resbuf, struct gss_svc_data *gsd) +{ + __be32 *p; + u32 verf_len; + + p = gsd->verf_start; + gsd->verf_start = NULL; + + /* If the reply stat is nonzero, don't wrap: */ + if (*(p-1) != rpc_success) + return NULL; + /* Skip the verifier: */ + p += 1; + verf_len = ntohl(*p++); + p += XDR_QUADLEN(verf_len); + /* move accept_stat to right place: */ + memcpy(p, p + 2, 4); + /* Also don't wrap if the accept stat is nonzero: */ + if (*p != rpc_success) { + resbuf->head[0].iov_len -= 2 * 4; + return NULL; + } + p++; + return p; +} + +static inline int +svcauth_gss_wrap_resp_integ(struct svc_rqst *rqstp) +{ + struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data; + struct rpc_gss_wire_cred *gc = &gsd->clcred; + struct xdr_buf *resbuf = &rqstp->rq_res; + struct xdr_buf integ_buf; + struct xdr_netobj mic; + struct kvec *resv; + __be32 *p; + int integ_offset, integ_len; + int stat = -EINVAL; + + p = svcauth_gss_prepare_to_wrap(resbuf, gsd); + if (p == NULL) + goto out; + integ_offset = (u8 *)(p + 1) - (u8 *)resbuf->head[0].iov_base; + integ_len = resbuf->len - integ_offset; + BUG_ON(integ_len % 4); + *p++ = htonl(integ_len); + *p++ = htonl(gc->gc_seq); + if (xdr_buf_subsegment(resbuf, &integ_buf, integ_offset, + integ_len)) + BUG(); + if (resbuf->tail[0].iov_base == NULL) { + if (resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE > PAGE_SIZE) + goto out_err; + resbuf->tail[0].iov_base = resbuf->head[0].iov_base + + resbuf->head[0].iov_len; + resbuf->tail[0].iov_len = 0; + resv = &resbuf->tail[0]; + } else { + resv = &resbuf->tail[0]; + } + mic.data = (u8 *)resv->iov_base + resv->iov_len + 4; + if (gss_get_mic(gsd->rsci->mechctx, &integ_buf, &mic)) + goto out_err; + svc_putnl(resv, mic.len); + memset(mic.data + mic.len, 0, + round_up_to_quad(mic.len) - mic.len); + resv->iov_len += XDR_QUADLEN(mic.len) << 2; + /* not strictly required: */ + resbuf->len += XDR_QUADLEN(mic.len) << 2; + BUG_ON(resv->iov_len > PAGE_SIZE); +out: + stat = 0; +out_err: + return stat; +} + +static inline int +svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp) +{ + struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data; + struct rpc_gss_wire_cred *gc = &gsd->clcred; + struct xdr_buf *resbuf = &rqstp->rq_res; + struct page **inpages = NULL; + __be32 *p, *len; + int offset; + int pad; + + p = svcauth_gss_prepare_to_wrap(resbuf, gsd); + if (p == NULL) + return 0; + len = p++; + offset = (u8 *)p - (u8 *)resbuf->head[0].iov_base; + *p++ = htonl(gc->gc_seq); + inpages = resbuf->pages; + /* XXX: Would be better to write some xdr helper functions for + * nfs{2,3,4}xdr.c that place the data right, instead of copying: */ + + /* + * If there is currently tail data, make sure there is + * room for the head, tail, and 2 * RPC_MAX_AUTH_SIZE in + * the page, and move the current tail data such that + * there is RPC_MAX_AUTH_SIZE slack space available in + * both the head and tail. + */ + if (resbuf->tail[0].iov_base) { + BUG_ON(resbuf->tail[0].iov_base >= resbuf->head[0].iov_base + + PAGE_SIZE); + BUG_ON(resbuf->tail[0].iov_base < resbuf->head[0].iov_base); + if (resbuf->tail[0].iov_len + resbuf->head[0].iov_len + + 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE) + return -ENOMEM; + memmove(resbuf->tail[0].iov_base + RPC_MAX_AUTH_SIZE, + resbuf->tail[0].iov_base, + resbuf->tail[0].iov_len); + resbuf->tail[0].iov_base += RPC_MAX_AUTH_SIZE; + } + /* + * If there is no current tail data, make sure there is + * room for the head data, and 2 * RPC_MAX_AUTH_SIZE in the + * allotted page, and set up tail information such that there + * is RPC_MAX_AUTH_SIZE slack space available in both the + * head and tail. + */ + if (resbuf->tail[0].iov_base == NULL) { + if (resbuf->head[0].iov_len + 2*RPC_MAX_AUTH_SIZE > PAGE_SIZE) + return -ENOMEM; + resbuf->tail[0].iov_base = resbuf->head[0].iov_base + + resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE; + resbuf->tail[0].iov_len = 0; + } + if (gss_wrap(gsd->rsci->mechctx, offset, resbuf, inpages)) + return -ENOMEM; + *len = htonl(resbuf->len - offset); + pad = 3 - ((resbuf->len - offset - 1)&3); + p = (__be32 *)(resbuf->tail[0].iov_base + resbuf->tail[0].iov_len); + memset(p, 0, pad); + resbuf->tail[0].iov_len += pad; + resbuf->len += pad; + return 0; +} + +static int +svcauth_gss_release(struct svc_rqst *rqstp) +{ + struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data; + struct rpc_gss_wire_cred *gc = &gsd->clcred; + struct xdr_buf *resbuf = &rqstp->rq_res; + int stat = -EINVAL; + struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id); + + if (gc->gc_proc != RPC_GSS_PROC_DATA) + goto out; + /* Release can be called twice, but we only wrap once. */ + if (gsd->verf_start == NULL) + goto out; + /* normally not set till svc_send, but we need it here: */ + /* XXX: what for? Do we mess it up the moment we call svc_putu32 + * or whatever? */ + resbuf->len = total_buf_len(resbuf); + switch (gc->gc_svc) { + case RPC_GSS_SVC_NONE: + break; + case RPC_GSS_SVC_INTEGRITY: + stat = svcauth_gss_wrap_resp_integ(rqstp); + if (stat) + goto out_err; + break; + case RPC_GSS_SVC_PRIVACY: + stat = svcauth_gss_wrap_resp_priv(rqstp); + if (stat) + goto out_err; + break; + /* + * For any other gc_svc value, svcauth_gss_accept() already set + * the auth_error appropriately; just fall through: + */ + } + +out: + stat = 0; +out_err: + if (rqstp->rq_client) + auth_domain_put(rqstp->rq_client); + rqstp->rq_client = NULL; + if (rqstp->rq_gssclient) + auth_domain_put(rqstp->rq_gssclient); + rqstp->rq_gssclient = NULL; + if (rqstp->rq_cred.cr_group_info) + put_group_info(rqstp->rq_cred.cr_group_info); + rqstp->rq_cred.cr_group_info = NULL; + if (gsd->rsci) + cache_put(&gsd->rsci->h, sn->rsc_cache); + gsd->rsci = NULL; + + return stat; +} + +static void +svcauth_gss_domain_release(struct auth_domain *dom) +{ + struct gss_domain *gd = container_of(dom, struct gss_domain, h); + + kfree(dom->name); + kfree(gd); +} + +static struct auth_ops svcauthops_gss = { + .name = "rpcsec_gss", + .owner = THIS_MODULE, + .flavour = RPC_AUTH_GSS, + .accept = svcauth_gss_accept, + .release = svcauth_gss_release, + .domain_release = svcauth_gss_domain_release, + .set_client = svcauth_gss_set_client, +}; + +static int rsi_cache_create_net(struct net *net) +{ + struct sunrpc_net *sn = net_generic(net, sunrpc_net_id); + struct cache_detail *cd; + int err; + + cd = cache_create_net(&rsi_cache_template, net); + if (IS_ERR(cd)) + return PTR_ERR(cd); + err = cache_register_net(cd, net); + if (err) { + cache_destroy_net(cd, net); + return err; + } + sn->rsi_cache = cd; + return 0; +} + +static void rsi_cache_destroy_net(struct net *net) +{ + struct sunrpc_net *sn = net_generic(net, sunrpc_net_id); + struct cache_detail *cd = sn->rsi_cache; + + sn->rsi_cache = NULL; + cache_purge(cd); + cache_unregister_net(cd, net); + cache_destroy_net(cd, net); +} + +static int rsc_cache_create_net(struct net *net) +{ + struct sunrpc_net *sn = net_generic(net, sunrpc_net_id); + struct cache_detail *cd; + int err; + + cd = cache_create_net(&rsc_cache_template, net); + if (IS_ERR(cd)) + return PTR_ERR(cd); + err = cache_register_net(cd, net); + if (err) { + cache_destroy_net(cd, net); + return err; + } + sn->rsc_cache = cd; + return 0; +} + +static void rsc_cache_destroy_net(struct net *net) +{ + struct sunrpc_net *sn = net_generic(net, sunrpc_net_id); + struct cache_detail *cd = sn->rsc_cache; + + sn->rsc_cache = NULL; + cache_purge(cd); + cache_unregister_net(cd, net); + cache_destroy_net(cd, net); +} + +int +gss_svc_init_net(struct net *net) +{ + int rv; + + rv = rsc_cache_create_net(net); + if (rv) + return rv; + rv = rsi_cache_create_net(net); + if (rv) + goto out1; + return 0; +out1: + rsc_cache_destroy_net(net); + return rv; +} + +void +gss_svc_shutdown_net(struct net *net) +{ + rsi_cache_destroy_net(net); + rsc_cache_destroy_net(net); +} + +int +gss_svc_init(void) +{ + return svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss); +} + +void +gss_svc_shutdown(void) +{ + svc_auth_unregister(RPC_AUTH_GSS); +} |