Package: nbd-server
Version: 1:3.2-2
Severity: important
Tags: patch
Dear Maintainer,
When a client requests an export list from the server,
the latter issues the message 'Error: negotiation failed'.
This is rather confusing, as the only 'problem' is (AFAICT)
that the negotiation phase did everything.
On a subsequent attempt to connect a block device, the server
fails altogether:
Client output:
--------------------
nasc0:root ~ 216 # /tmp/nbd-client.master -l nass0
Negotiation: ..
nasc0-nbd0
nasc0:root ~ 217 # /tmp/nbd-client.master nass0 -N nasc0-nbd0 /dev/nbd0
Negotiation: ..size = 856941734MBError: Exported device is too big for
me. Get 64-bit machine :-(
Exiting.
--------------------
Server output:
--------------------
nass0:root ~ 135 # /tmp/nbd-server.master -d -C /etc/nbd-server/config
Error: negotiation failed
Exiting.
Error: Read failed: Connection reset by peer
Exiting.
--------------------
From a tcpdump, it can be observed that the syslog messages end up
on the client socket, which makes the client choke, naturally.
I tested this for the latest git version, and the same problem
occurs. I have traced the problem to the fact that negotiate(),
in two locations, closes the socket, and returns NULL , after which
serveloop also closes it, actually closing the syslog socket instead.
The next accept() returns that same filedescriptor, which syslog()
still thinks it owns.
I'm attaching a patch against git revision
902c07e75f12459c55d79f450a0fb9c1e7da02e5, which improves the error
reporting, and fixes the failure for the connect after the LIST.
Note: I added the message 'Session terminated by client', because
the 'ABORT' might also be intended to be used as an irregular
end-of-session (in the future?), besides indicating a regular
end-of-session after a LIST.
Kind regards,
Rogier.
--------------------------------------------
diff --git a/nbd-server.c b/nbd-server.c
index 69ee2a4..e905281 100644
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -1532,13 +1532,18 @@ static CLIENT* handle_export_name(uint32_t opt, int
net, GArray* servers, uint32
char* name;
int i;
- if (read(net, &namelen, sizeof(namelen)) < 0)
+ if (read(net, &namelen, sizeof(namelen)) < 0) {
err("Negotiation failed/7: %m");
+ return NULL;
+ }
namelen = ntohl(namelen);
name = malloc(namelen+1);
name[namelen]=0;
- if (read(net, name, namelen) < 0)
+ if (read(net, name, namelen) < 0) {
err("Negotiation failed/8: %m");
+ free(name);
+ return NULL;
+ }
for(i=0; i<servers->len; i++) {
SERVER* serve = &(g_array_index(servers, SERVER, i));
if(!strcmp(serve->servename, name)) {
@@ -1553,6 +1558,7 @@ static CLIENT* handle_export_name(uint32_t opt, int net,
GArray* servers, uint32
return client;
}
}
+ err("Negotiation failed/8a: Requested export not found");
free(name);
return NULL;
}
@@ -1639,7 +1645,7 @@ CLIENT* negotiate(int net, CLIENT *client, GArray*
servers, int phase) {
err_nonfatal("Negotiation failed/5: %m");
magic = ntohll(magic);
if(magic != opts_magic) {
- close(net);
+ err_nonfatal("Negotiation failed/5a: magic
mismatch");
return NULL;
}
if (read(net, &opt, sizeof(opt)) < 0)
@@ -1664,7 +1670,7 @@ CLIENT* negotiate(int net, CLIENT *client, GArray*
servers, int phase) {
}
} while((opt != NBD_OPT_EXPORT_NAME) && (opt != NBD_OPT_ABORT));
if(opt == NBD_OPT_ABORT) {
- close(net);
+ err_nonfatal("Session terminated by client");
return NULL;
}
}
@@ -2305,7 +2311,6 @@ void serveloop(GArray* servers) {
}
client = negotiate(net, NULL, servers, NEG_INIT
| NEG_MODERN);
if(!client) {
- err_nonfatal("negotiation failed");
close(net);
continue;
}
--------------------------------------------
-- System Information:
Debian Release: wheezy/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: i386 (x86_64)
Kernel: Linux 3.2.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages nbd-server depends on:
ii adduser 3.113+nmu3
ii debconf [debconf-2.0] 1.5.46
ii libc6 2.13-37
ii libglib2.0-0 2.33.12+really2.32.4-3
ii ucf 3.0025+nmu3
nbd-server recommends no packages.
nbd-server suggests no packages.
-- debconf information excluded
--
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