SUNRPC: Go back to using gsd->body_start

Now that svcauth_gss_prepare_to_wrap() no longer computes the
location of RPC header fields in the response buffer,
svcauth_gss_accept() can save the location of the databody
rather than the location of the verifier.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 7e7fda9a3e4ea68397423debb8576a95c6d06553..28e977c89a5a9257815fce13be9f0e7c0fc6687e 100644 (file)
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -71,9 +71,7 @@
 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;
+       u32                             gsd_databody_offset;
        struct rsc                      *rsci;
 
        /* for temporary results */
@@ -1595,7 +1593,7 @@ svcauth_gss_accept(struct svc_rqst *rqstp)
        if (!svcdata)
                goto auth_err;
        rqstp->rq_auth_data = svcdata;
-       svcdata->verf_start = NULL;
+       svcdata->gsd_databody_offset = 0;
        svcdata->rsci = NULL;
        gc = &svcdata->clcred;
 
@@ -1647,11 +1645,11 @@ svcauth_gss_accept(struct svc_rqst *rqstp)
                goto complete;
        case RPC_GSS_PROC_DATA:
                rqstp->rq_auth_stat = rpcsec_gsserr_ctxproblem;
-               svcdata->verf_start = xdr_reserve_space(&rqstp->rq_res_stream, 0);
                if (!svcauth_gss_encode_verf(rqstp, rsci->mechctx, gc->gc_seq))
                        goto auth_err;
                if (!svcxdr_set_accept_stat(rqstp))
                        goto auth_err;
+               svcdata->gsd_databody_offset = xdr_stream_pos(&rqstp->rq_res_stream);
                rqstp->rq_cred = rsci->cred;
                get_group_info(rsci->cred.cr_group_info);
                rqstp->rq_auth_stat = rpc_autherr_badcred;
@@ -1705,30 +1703,24 @@ out:
        return ret;
 }
 
-static __be32 *
+static u32
 svcauth_gss_prepare_to_wrap(struct svc_rqst *rqstp, struct gss_svc_data *gsd)
 {
-       __be32 *p;
-       u32 verf_len;
+       u32 offset;
 
-       p = gsd->verf_start;
-       gsd->verf_start = NULL;
+       /* Release can be called twice, but we only wrap once. */
+       offset = gsd->gsd_databody_offset;
+       gsd->gsd_databody_offset = 0;
 
        /* AUTH_ERROR replies are not wrapped. */
        if (rqstp->rq_auth_stat != rpc_auth_ok)
-               return NULL;
-
-       /* Skip the verifier: */
-       p += 1;
-       verf_len = ntohl(*p++);
-       p += XDR_QUADLEN(verf_len);
+               return 0;
 
        /* Also don't wrap if the accept_stat is nonzero: */
        if (*rqstp->rq_accept_statp != rpc_success)
-               return NULL;
+               return 0;
 
-       p++;
-       return p;
+       return offset;
 }
 
 /*
@@ -1756,21 +1748,21 @@ static int svcauth_gss_wrap_integ(struct svc_rqst *rqstp)
        struct xdr_buf *buf = xdr->buf;
        struct xdr_buf databody_integ;
        struct xdr_netobj checksum;
-       u32 offset, len, maj_stat;
-       __be32 *p;
+       u32 offset, maj_stat;
 
-       p = svcauth_gss_prepare_to_wrap(rqstp, gsd);
-       if (p == NULL)
+       offset = svcauth_gss_prepare_to_wrap(rqstp, gsd);
+       if (!offset)
                goto out;
 
-       offset = (u8 *)(p + 1) - (u8 *)buf->head[0].iov_base;
-       len = buf->len - offset;
-       if (xdr_buf_subsegment(buf, &databody_integ, offset, len))
+       if (xdr_buf_subsegment(buf, &databody_integ, offset + XDR_UNIT,
+                              buf->len - offset - XDR_UNIT))
                goto wrap_failed;
        /* Buffer space for these has already been reserved in
         * svcauth_gss_accept(). */
-       *p++ = cpu_to_be32(len);
-       *p = cpu_to_be32(gc->gc_seq);
+       if (xdr_encode_word(buf, offset, databody_integ.len))
+               goto wrap_failed;
+       if (xdr_encode_word(buf, offset + XDR_UNIT, gc->gc_seq))
+               goto wrap_failed;
 
        checksum.data = gsd->gsd_scratch;
        maj_stat = gss_get_mic(gsd->rsci->mechctx, &databody_integ, &checksum);
@@ -1817,17 +1809,19 @@ static int svcauth_gss_wrap_priv(struct svc_rqst *rqstp)
        struct kvec *head = buf->head;
        struct kvec *tail = buf->tail;
        u32 offset, pad, maj_stat;
-       __be32 *p, *lenp;
+       __be32 *p;
 
-       p = svcauth_gss_prepare_to_wrap(rqstp, gsd);
-       if (p == NULL)
+       offset = svcauth_gss_prepare_to_wrap(rqstp, gsd);
+       if (!offset)
                return 0;
 
-       lenp = p++;
-       offset = (u8 *)p - (u8 *)head->iov_base;
-       /* Buffer space for this field has already been reserved
-        * in svcauth_gss_accept(). */
-       *p = cpu_to_be32(gc->gc_seq);
+       /*
+        * Buffer space for this field has already been reserved
+        * in svcauth_gss_accept(). Note that the GSS sequence
+        * number is encrypted along with the RPC reply payload.
+        */
+       if (xdr_encode_word(buf, offset + XDR_UNIT, gc->gc_seq))
+               goto wrap_failed;
 
        /*
         * If there is currently tail data, make sure there is
@@ -1863,12 +1857,15 @@ static int svcauth_gss_wrap_priv(struct svc_rqst *rqstp)
                tail->iov_len = 0;
        }
 
-       maj_stat = gss_wrap(gsd->rsci->mechctx, offset, buf, buf->pages);
+       maj_stat = gss_wrap(gsd->rsci->mechctx, offset + XDR_UNIT, buf,
+                           buf->pages);
        if (maj_stat != GSS_S_COMPLETE)
                goto bad_wrap;
 
-       *lenp = cpu_to_be32(buf->len - offset);
-       pad = xdr_pad_size(buf->len - offset);
+       /* Wrapping can change the size of databody_priv. */
+       if (xdr_encode_word(buf, offset, buf->len - offset - XDR_UNIT))
+               goto wrap_failed;
+       pad = xdr_pad_size(buf->len - offset - XDR_UNIT);
        p = (__be32 *)(tail->iov_base + tail->iov_len);
        memset(p, 0, pad);
        tail->iov_len += pad;
@@ -1908,9 +1905,6 @@ svcauth_gss_release(struct svc_rqst *rqstp)
        gc = &gsd->clcred;
        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;
 
        switch (gc->gc_svc) {
        case RPC_GSS_SVC_NONE: