gss_krb5: Added and improved code comments (7561042f) · Commits · e / devices / android_kernel_xiaomi_markw

net/sunrpc/auth_gss/auth_gss.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -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 −0

Original line number	Diff line number	Diff line
		@@ -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 −0

Original line number	Diff line number	Diff line
		@@ -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;