Merge tag '6.17-rc6-ksmbd-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - Two fixes for remaining_data_length and offset checks in receive path

 - Don't go over max SGEs which caused smbdirect send to fail (and
   trigger disconnect)

* tag '6.17-rc6-ksmbd-fixes' of git://git.samba.org/ksmbd:
  ksmbd: smbdirect: verify remaining_data_length respects max_fragmented_recv_size
  ksmbd: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer
  smb: server: let smb_direct_writev() respect SMB_DIRECT_MAX_SEND_SGES

Author: torvalds

fs/smb/server/transport_rdma.c

@@ -554,7 +554,7 @@ static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
 	case SMB_DIRECT_MSG_DATA_TRANSFER: {
 		struct smb_direct_data_transfer *data_transfer =
 			(struct smb_direct_data_transfer *)recvmsg->packet;
-		unsigned int data_length;
+		u32 remaining_data_length, data_offset, data_length;
 		int avail_recvmsg_count, receive_credits;
 
 		if (wc->byte_len <
@@ -564,15 +564,25 @@ static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
 			return;
 		}
 
+		remaining_data_length = le32_to_cpu(data_transfer->remaining_data_length);
 		data_length = le32_to_cpu(data_transfer->data_length);
-		if (data_length) {
-			if (wc->byte_len < sizeof(struct smb_direct_data_transfer) +
-			    (u64)data_length) {
-				put_recvmsg(t, recvmsg);
-				smb_direct_disconnect_rdma_connection(t);
-				return;
-			}
+		data_offset = le32_to_cpu(data_transfer->data_offset);
+		if (wc->byte_len < data_offset ||
+		    wc->byte_len < (u64)data_offset + data_length) {
+			put_recvmsg(t, recvmsg);
+			smb_direct_disconnect_rdma_connection(t);
+			return;
+		}
+		if (remaining_data_length > t->max_fragmented_recv_size ||
+		    data_length > t->max_fragmented_recv_size ||
+		    (u64)remaining_data_length + (u64)data_length >
+		    (u64)t->max_fragmented_recv_size) {
+			put_recvmsg(t, recvmsg);
+			smb_direct_disconnect_rdma_connection(t);
+			return;
+		}
 
+		if (data_length) {
 			if (t->full_packet_received)
 				recvmsg->first_segment = true;
 
@@ -1209,78 +1219,130 @@ static int smb_direct_writev(struct ksmbd_transport *t,
 			     bool need_invalidate, unsigned int remote_key)
 {
 	struct smb_direct_transport *st = smb_trans_direct_transfort(t);
-	int remaining_data_length;
-	int start, i, j;
-	int max_iov_size = st->max_send_size -
+	size_t remaining_data_length;
+	size_t iov_idx;
+	size_t iov_ofs;
+	size_t max_iov_size = st->max_send_size -
 			sizeof(struct smb_direct_data_transfer);
 	int ret;
-	struct kvec vec;
 	struct smb_direct_send_ctx send_ctx;
+	int error = 0;
 
 	if (st->status != SMB_DIRECT_CS_CONNECTED)
 		return -ENOTCONN;
 
 	//FIXME: skip RFC1002 header..
+	if (WARN_ON_ONCE(niovs <= 1 || iov[0].iov_len != 4))
+		return -EINVAL;
 	buflen -= 4;
+	iov_idx = 1;
+	iov_ofs = 0;
 
 	remaining_data_length = buflen;
 	ksmbd_debug(RDMA, "Sending smb (RDMA): smb_len=%u\n", buflen);
 
 	smb_direct_send_ctx_init(st, &send_ctx, need_invalidate, remote_key);
-	start = i = 1;
-	buflen = 0;
-	while (true) {
-		buflen += iov[i].iov_len;
-		if (buflen > max_iov_size) {
-			if (i > start) {
-				remaining_data_length -=
-					(buflen - iov[i].iov_len);
-				ret = smb_direct_post_send_data(st, &send_ctx,
-								&iov[start], i - start,
-								remaining_data_length);
-				if (ret)
+	while (remaining_data_length) {
+		struct kvec vecs[SMB_DIRECT_MAX_SEND_SGES - 1]; /* minus smbdirect hdr */
+		size_t possible_bytes = max_iov_size;
+		size_t possible_vecs;
+		size_t bytes = 0;
+		size_t nvecs = 0;
+
+		/*
+		 * For the last message remaining_data_length should be
+		 * have been 0 already!
+		 */
+		if (WARN_ON_ONCE(iov_idx >= niovs)) {
+			error = -EINVAL;
+			goto done;
+		}
+
+		/*
+		 * We have 2 factors which limit the arguments we pass
+		 * to smb_direct_post_send_data():
+		 *
+		 * 1. The number of supported sges for the send,
+		 *    while one is reserved for the smbdirect header.
+		 *    And we currently need one SGE per page.
+		 * 2. The number of negotiated payload bytes per send.
+		 */
+		possible_vecs = min_t(size_t, ARRAY_SIZE(vecs), niovs - iov_idx);
+
+		while (iov_idx < niovs && possible_vecs && possible_bytes) {
+			struct kvec *v = &vecs[nvecs];
+			int page_count;
+
+			v->iov_base = ((u8 *)iov[iov_idx].iov_base) + iov_ofs;
+			v->iov_len = min_t(size_t,
+					   iov[iov_idx].iov_len - iov_ofs,
+					   possible_bytes);
+			page_count = get_buf_page_count(v->iov_base, v->iov_len);
+			if (page_count > possible_vecs) {
+				/*
+				 * If the number of pages in the buffer
+				 * is to much (because we currently require
+				 * one SGE per page), we need to limit the
+				 * length.
+				 *
+				 * We know possible_vecs is at least 1,
+				 * so we always keep the first page.
+				 *
+				 * We need to calculate the number extra
+				 * pages (epages) we can also keep.
+				 *
+				 * We calculate the number of bytes in the
+				 * first page (fplen), this should never be
+				 * larger than v->iov_len because page_count is
+				 * at least 2, but adding a limitation feels
+				 * better.
+				 *
+				 * Then we calculate the number of bytes (elen)
+				 * we can keep for the extra pages.
+				 */
+				size_t epages = possible_vecs - 1;
+				size_t fpofs = offset_in_page(v->iov_base);
+				size_t fplen = min_t(size_t, PAGE_SIZE - fpofs, v->iov_len);
+				size_t elen = min_t(size_t, v->iov_len - fplen, epages*PAGE_SIZE);
+
+				v->iov_len = fplen + elen;
+				page_count = get_buf_page_count(v->iov_base, v->iov_len);
+				if (WARN_ON_ONCE(page_count > possible_vecs)) {
+					/*
+					 * Something went wrong in the above
+					 * logic...
+					 */
+					error = -EINVAL;
 					goto done;
-			} else {
-				/* iov[start] is too big, break it */
-				int nvec  = (buflen + max_iov_size - 1) /
-						max_iov_size;
-
-				for (j = 0; j < nvec; j++) {
-					vec.iov_base =
-						(char *)iov[start].iov_base +
-						j * max_iov_size;
-					vec.iov_len =
-						min_t(int, max_iov_size,
-						      buflen - max_iov_size * j);
-					remaining_data_length -= vec.iov_len;
-					ret = smb_direct_post_send_data(st, &send_ctx, &vec, 1,
-									remaining_data_length);
-					if (ret)
-						goto done;
 				}
-				i++;
-				if (i == niovs)
-					break;
 			}
-			start = i;
-			buflen = 0;
-		} else {
-			i++;
-			if (i == niovs) {
-				/* send out all remaining vecs */
-				remaining_data_length -= buflen;
-				ret = smb_direct_post_send_data(st, &send_ctx,
-								&iov[start], i - start,
-								remaining_data_length);
-				if (ret)
-					goto done;
-				break;
+			possible_vecs -= page_count;
+			nvecs += 1;
+			possible_bytes -= v->iov_len;
+			bytes += v->iov_len;
+
+			iov_ofs += v->iov_len;
+			if (iov_ofs >= iov[iov_idx].iov_len) {
+				iov_idx += 1;
+				iov_ofs = 0;
 			}
 		}
+
+		remaining_data_length -= bytes;
+
+		ret = smb_direct_post_send_data(st, &send_ctx,
+						vecs, nvecs,
+						remaining_data_length);
+		if (unlikely(ret)) {
+			error = ret;
+			goto done;
+		}
 	}
 
 done:
 	ret = smb_direct_flush_send_list(st, &send_ctx, true);
+	if (unlikely(!ret && error))
+		ret = error;
 
 	/*
 	 * As an optimization, we don't wait for individual I/O to finish
@@ -1744,6 +1806,11 @@ static int smb_direct_init_params(struct smb_direct_transport *t,
 		return -EINVAL;
 	}
 
+	if (device->attrs.max_send_sge < SMB_DIRECT_MAX_SEND_SGES) {
+		pr_err("warning: device max_send_sge = %d too small\n",
+		       device->attrs.max_send_sge);
+		return -EINVAL;
+	}
 	if (device->attrs.max_recv_sge < SMB_DIRECT_MAX_RECV_SGES) {
 		pr_err("warning: device max_recv_sge = %d too small\n",
 		       device->attrs.max_recv_sge);
@@ -1767,7 +1834,7 @@ static int smb_direct_init_params(struct smb_direct_transport *t,
 
 	cap->max_send_wr = max_send_wrs;
 	cap->max_recv_wr = t->recv_credit_max;
-	cap->max_send_sge = max_sge_per_wr;
+	cap->max_send_sge = SMB_DIRECT_MAX_SEND_SGES;
 	cap->max_recv_sge = SMB_DIRECT_MAX_RECV_SGES;
 	cap->max_inline_data = 0;
 	cap->max_rdma_ctxs = t->max_rw_credits;