4:54 p.m.
Similar to the earlier patch for structured reply errors, it's worth
logging (at least through debug) any error messages that the server
sends alongside NBD_REP_ERR. And given our earlier changes, it
doesn't really impact the size of struct nbd_handle.
---
generator/states-newstyle-opt-go.c | 5 ++--
.../states-newstyle-opt-set-meta-context.c | 6 +++-
generator/states-newstyle-opt-starttls.c | 8 ++---
.../states-newstyle-opt-structured-reply.c | 6 +++-
generator/states-newstyle.c | 29 +++++++++++++++++++
lib/internal.h | 1 +
6 files changed, 47 insertions(+), 8 deletions(-)
diff --git a/generator/states-newstyle-opt-go.c b/generator/states-newstyle-opt-go.c
index 3458f09..91a85ef 100644
--- a/generator/states-newstyle-opt-go.c
+++ b/generator/states-newstyle-opt-go.c
@@ -147,9 +147,10 @@
SET_NEXT_STATE (%^OPT_EXPORT_NAME.START);
return 0;
default:
+ if (handle_reply_error (h) == 0)
+ set_error (0, "handshake: unknown reply from NBD_OPT_GO: 0x%" PRIx32,
+ reply);
SET_NEXT_STATE (%.DEAD);
- set_error (0, "handshake: unknown reply from NBD_OPT_GO: 0x%" PRIx32,
- reply);
return -1;
}
diff --git a/generator/states-newstyle-opt-set-meta-context.c
b/generator/states-newstyle-opt-set-meta-context.c
index 94120e2..a00a411 100644
--- a/generator/states-newstyle-opt-set-meta-context.c
+++ b/generator/states-newstyle-opt-set-meta-context.c
@@ -200,7 +200,11 @@
break;
default:
/* Anything else is an error, ignore it */
- /* XXX display any error message if NBD_REP_ERR_? */
+ if (handle_reply_error (h) == -1) {
+ SET_NEXT_STATE (%.DEAD);
+ return -1;
+ }
+
debug (h, "handshake: unexpected error from "
"NBD_OPT_SET_META_CONTEXT (%" PRIu32 ")", reply);
SET_NEXT_STATE (%^OPT_GO.START);
diff --git a/generator/states-newstyle-opt-starttls.c
b/generator/states-newstyle-opt-starttls.c
index e994ffd..61f254f 100644
--- a/generator/states-newstyle-opt-starttls.c
+++ b/generator/states-newstyle-opt-starttls.c
@@ -83,9 +83,10 @@
return 0;
default:
- if (!NBD_REP_IS_ERR (reply))
- debug (h,
- "server is confused by NBD_OPT_STARTTLS, continuing anyway");
+ if (handle_reply_error (h) == -1) {
+ SET_NEXT_STATE (%.DEAD);
+ return -1;
+ }
/* Server refused to upgrade to TLS. If h->tls is not require (2)
* then we can continue unencrypted.
@@ -100,7 +101,6 @@
debug (h,
"server refused TLS (%s), continuing with unencrypted connection",
reply == NBD_REP_ERR_POLICY ? "policy" : "not
supported");
- /* XXX: capture instead of skip server's payload to NBD_REP_ERR*? */
SET_NEXT_STATE (%^OPT_STRUCTURED_REPLY.START);
return 0;
}
diff --git a/generator/states-newstyle-opt-structured-reply.c
b/generator/states-newstyle-opt-structured-reply.c
index d755411..65d5958 100644
--- a/generator/states-newstyle-opt-structured-reply.c
+++ b/generator/states-newstyle-opt-structured-reply.c
@@ -67,7 +67,11 @@
h->structured_replies = true;
break;
default:
- /* XXX: capture instead of skip server's payload to NBD_REP_ERR*? */
+ if (handle_reply_error (h) == -1) {
+ SET_NEXT_STATE (%.DEAD);
+ return -1;
+ }
+
debug (h, "structured replies are not supported by this server");
h->structured_replies = false;
break;
diff --git a/generator/states-newstyle.c b/generator/states-newstyle.c
index 369df0f..8a4eec6 100644
--- a/generator/states-newstyle.c
+++ b/generator/states-newstyle.c
@@ -77,6 +77,35 @@ prepare_for_reply_payload (struct nbd_handle *h, uint32_t opt)
return 0;
}
+/* Check an unexpected server reply. If it is an error, log any
+ * message from the server and return 0; otherwise, return -1.
+ */
+static int
+handle_reply_error (struct nbd_handle *h)
+{
+ uint32_t len;
+ uint32_t reply;
+
+ len = be32toh (h->sbuf.or.option_reply.replylen);
+ reply = be32toh (h->sbuf.or.option_reply.reply);
+ if (!NBD_REP_IS_ERR (reply)) {
+ set_error (0, "handshake: unexpected option reply type %d", reply);
+ return -1;
+ }
+
+ assert (NBD_MAX_STRING < sizeof h->sbuf.or.payload);
+ if (len > NBD_MAX_STRING) {
+ set_error (0, "handshake: option error string too long");
+ return -1;
+ }
+
+ if (len > 0)
+ debug (h, "handshake: server error message: %.*s", (int) len,
+ h->sbuf.or.payload.err_msg);
+
+ return 0;
+}
+
/* State machine for parsing the fixed newstyle handshake. */
/* STATE MACHINE */ {
diff --git a/lib/internal.h b/lib/internal.h
index 5f19279..9acc1b4 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -127,6 +127,7 @@ struct nbd_handle {
struct nbd_fixed_new_option_reply_meta_context context;
char str[NBD_MAX_STRING];
} __attribute__((packed)) context;
+ char err_msg[NBD_MAX_STRING];
} payload;
} __attribute__((packed)) or;
struct nbd_export_name_option_reply export_name_reply;
--
2.20.1