Ensure that the server is not sending unexpected chunk lengths
for either the NONE or the OFFSET_DATA chunk, nor unexpected
hole length for OFFSET_HOLE. This will flag any server as
broken that responds to a zero-length read with an OFFSET_DATA
(what our server currently does, but that's about to be fixed)
or with OFFSET_HOLE, even though we previously fixed our client
to never be able to send such a request over the wire.
Signed-off-by: Eric Blake <ebl...@redhat.com>
Message-Id: <20171108215703.9295-7-ebl...@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
block/nbd-client.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/block/nbd-client.c b/block/nbd-client.c
index 0a675d0fab..bcfed0133d 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -216,7 +216,7 @@ static int
nbd_parse_offset_hole_payload(NBDStructuredReplyChunk *chunk,
offset = payload_advance64(&payload);
hole_size = payload_advance32(&payload);
- if (offset < orig_offset || hole_size > qiov->size ||
+ if (!hole_size || offset < orig_offset || hole_size > qiov->size ||
offset > orig_offset + qiov->size - hole_size) {
error_setg(errp, "Protocol error: server sent chunk exceeding
requested"
" region");
@@ -281,7 +281,8 @@ static int
nbd_co_receive_offset_data_payload(NBDClientSession *s,
assert(nbd_reply_is_structured(&s->reply));
- if (chunk->length < sizeof(offset)) {
+ /* The NBD spec requires at least one byte of payload */
+ if (chunk->length <= sizeof(offset)) {
error_setg(errp, "Protocol error: invalid payload for "
"NBD_REPLY_TYPE_OFFSET_DATA");
return -EINVAL;
@@ -293,6 +294,7 @@ static int
nbd_co_receive_offset_data_payload(NBDClientSession *s,
be64_to_cpus(&offset);
data_size = chunk->length - sizeof(offset);
+ assert(data_size);
if (offset < orig_offset || data_size > qiov->size ||
offset > orig_offset + qiov->size - data_size) {
error_setg(errp, "Protocol error: server sent chunk exceeding
requested"
@@ -411,6 +413,11 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
" NBD_REPLY_FLAG_DONE flag set");
return -EINVAL;
}
+ if (chunk->length) {
+ error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk with"
+ " nonzero length");
+ return -EINVAL;
+ }
return 0;
}
--
2.13.6
