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gss_krb5: Added and improved code comments

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Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Kevin Coffman 2010-03-17 13:02:47 -04:00 committed by Trond Myklebust
parent 725f2865d4
commit 7561042fb7
3 changed files with 38 additions and 3 deletions
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12
net/sunrpc/auth_gss/auth_gss.c
View File

@ -1316,15 +1316,21 @@ gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
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: */
/*
* Give the tail its own page, in case we need extra space in the
* head when wrapping:
*
* call_allocate() allocates twice the slack space required
* by the authentication flavor to rq_callsize.
* For GSS, slack is GSS_CRED_SLACK.
*/
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, offset, snd_buf, inpages);
/* RPC_SLACK_SPACE should prevent this ever happening: */
/* 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

14
net/sunrpc/auth_gss/gss_mech_switch.c
View File

@ -285,6 +285,20 @@ gss_verify_mic(struct gss_ctx *context_handle,
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,

15
net/sunrpc/auth_gss/svcauth_gss.c
View File

@ -1315,6 +1315,14 @@ svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp)
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);
@ -1327,6 +1335,13 @@ svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp)
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;