RPCSEC_GSS: client-side privacy support

 Add the code to the client side to handle privacy.  This is dead code until
 we actually add privacy support to krb5.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index dc95b79..5e48720 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -43,6 +43,7 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/pagemap.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/auth.h>
 #include <linux/sunrpc/auth_gss.h>
@@ -975,6 +976,114 @@ gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
        return 0;
 }
 
+static void
+priv_release_snd_buf(struct rpc_rqst *rqstp)
+{
+       int i;
+
+       for (i=0; i < rqstp->rq_enc_pages_num; i++)
+               __free_page(rqstp->rq_enc_pages[i]);
+       kfree(rqstp->rq_enc_pages);
+}
+
+static int
+alloc_enc_pages(struct rpc_rqst *rqstp)
+{
+       struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
+       int first, last, i;
+
+       if (snd_buf->page_len == 0) {
+               rqstp->rq_enc_pages_num = 0;
+               return 0;
+       }
+
+       first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
+       last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_CACHE_SHIFT;
+       rqstp->rq_enc_pages_num = last - first + 1 + 1;
+       rqstp->rq_enc_pages
+               = kmalloc(rqstp->rq_enc_pages_num * sizeof(struct page *),
+                               GFP_NOFS);
+       if (!rqstp->rq_enc_pages)
+               goto out;
+       for (i=0; i < rqstp->rq_enc_pages_num; i++) {
+               rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
+               if (rqstp->rq_enc_pages[i] == NULL)
+                       goto out_free;
+       }
+       rqstp->rq_release_snd_buf = priv_release_snd_buf;
+       return 0;
+out_free:
+       for (i--; i >= 0; i--) {
+               __free_page(rqstp->rq_enc_pages[i]);
+       }
+out:
+       return -EAGAIN;
+}
+
+static inline int
+gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
+               kxdrproc_t encode, struct rpc_rqst *rqstp, u32 *p, void *obj)
+{
+       struct xdr_buf  *snd_buf = &rqstp->rq_snd_buf;
+       u32             offset;
+       u32             maj_stat;
+       int             status;
+       u32             *opaque_len;
+       struct page     **inpages;
+       int             first;
+       int             pad;
+       struct kvec     *iov;
+       char            *tmp;
+
+       opaque_len = p++;
+       offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
+       *p++ = htonl(rqstp->rq_seqno);
+
+       status = encode(rqstp, p, obj);
+       if (status)
+               return status;
+
+       status = alloc_enc_pages(rqstp);
+       if (status)
+               return status;
+       first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
+       inpages = snd_buf->pages + first;
+       snd_buf->pages = rqstp->rq_enc_pages;
+       snd_buf->page_base -= first << PAGE_CACHE_SHIFT;
+       /* Give the tail its own page, in case we need extra space in the
+        * head when wrapping: */
+       if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
+               tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
+               memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
+               snd_buf->tail[0].iov_base = tmp;
+       }
+       maj_stat = gss_wrap(ctx->gc_gss_ctx, GSS_C_QOP_DEFAULT, offset,
+                               snd_buf, inpages);
+       /* RPC_SLACK_SPACE should prevent this ever happening: */
+       BUG_ON(snd_buf->len > snd_buf->buflen);
+        status = -EIO;
+       /* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
+        * done anyway, so it's safe to put the request on the wire: */
+       if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+               cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
+       else if (maj_stat)
+               return status;
+
+       *opaque_len = htonl(snd_buf->len - offset);
+       /* guess whether we're in the head or the tail: */
+       if (snd_buf->page_len || snd_buf->tail[0].iov_len)
+               iov = snd_buf->tail;
+       else
+               iov = snd_buf->head;
+       p = iov->iov_base + iov->iov_len;
+       pad = 3 - ((snd_buf->len - offset - 1) & 3);
+       memset(p, 0, pad);
+       iov->iov_len += pad;
+       snd_buf->len += pad;
+
+       return 0;
+}
+
 static int
 gss_wrap_req(struct rpc_task *task,
             kxdrproc_t encode, void *rqstp, u32 *p, void *obj)
@@ -1002,6 +1111,8 @@ gss_wrap_req(struct rpc_task *task,
                                                                rqstp, p, obj);
                        break;
                        case RPC_GSS_SVC_PRIVACY:
+                       status = gss_wrap_req_priv(cred, ctx, encode,
+                                       rqstp, p, obj);
                        break;
        }
 out:
@@ -1048,6 +1159,36 @@ gss_unwrap_resp_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
        return 0;
 }
 
+static inline int
+gss_unwrap_resp_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
+               struct rpc_rqst *rqstp, u32 **p)
+{
+       struct xdr_buf  *rcv_buf = &rqstp->rq_rcv_buf;
+       u32 offset;
+       u32 opaque_len;
+       u32 maj_stat;
+       int status = -EIO;
+
+       opaque_len = ntohl(*(*p)++);
+       offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
+       if (offset + opaque_len > rcv_buf->len)
+               return status;
+       /* remove padding: */
+       rcv_buf->len = offset + opaque_len;
+
+       maj_stat = gss_unwrap(ctx->gc_gss_ctx, NULL,
+                       offset, rcv_buf);
+       if (maj_stat == GSS_S_CONTEXT_EXPIRED)
+               cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
+       if (maj_stat != GSS_S_COMPLETE)
+               return status;
+       if (ntohl(*(*p)++) != rqstp->rq_seqno)
+               return status;
+
+       return 0;
+}
+
+
 static int
 gss_unwrap_resp(struct rpc_task *task,
                kxdrproc_t decode, void *rqstp, u32 *p, void *obj)
@@ -1057,6 +1198,8 @@ gss_unwrap_resp(struct rpc_task *task,
                        gc_base);
        struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
        u32             *savedp = p;
+       struct kvec     *head = ((struct rpc_rqst *)rqstp)->rq_rcv_buf.head;
+       int             savedlen = head->iov_len;
        int             status = -EIO;
 
        if (ctx->gc_proc != RPC_GSS_PROC_DATA)
@@ -1070,10 +1213,14 @@ gss_unwrap_resp(struct rpc_task *task,
                                goto out;
                        break;
                        case RPC_GSS_SVC_PRIVACY:
+                       status = gss_unwrap_resp_priv(cred, ctx, rqstp, &p);
+                       if (status)
+                               goto out;
                        break;
        }
        /* take into account extra slack for integrity and privacy cases: */
-       task->tk_auth->au_rslack = task->tk_auth->au_verfsize + (p - savedp);
+       task->tk_auth->au_rslack = task->tk_auth->au_verfsize + (p - savedp)
+                                               + (savedlen - head->iov_len);
 out_decode:
        status = decode(rqstp, p, obj);
 out: