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-rw-r--r--gnu/packages/patches/qemu-CVE-2017-9524.patch287
1 files changed, 287 insertions, 0 deletions
diff --git a/gnu/packages/patches/qemu-CVE-2017-9524.patch b/gnu/packages/patches/qemu-CVE-2017-9524.patch
new file mode 100644
index 0000000000..57160055e3
--- /dev/null
+++ b/gnu/packages/patches/qemu-CVE-2017-9524.patch
@@ -0,0 +1,287 @@
+Fix CVE-2017-9524:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-9524
+http://seclists.org/oss-sec/2017/q2/454
+
+Patches copied from upstream source repository:
+
+http://git.qemu.org/?p=qemu.git;a=commitdiff;h=df8ad9f128c15aa0a0ebc7b24e9a22c9775b67af
+http://git.qemu.org/?p=qemu.git;a=commitdiff;h=0c9390d978cbf61e8f16c9f580fa96b305c43568
+
+From df8ad9f128c15aa0a0ebc7b24e9a22c9775b67af Mon Sep 17 00:00:00 2001
+From: Eric Blake <eblake@redhat.com>
+Date: Fri, 26 May 2017 22:04:21 -0500
+Subject: [PATCH] nbd: Fully initialize client in case of failed negotiation
+
+If a non-NBD client connects to qemu-nbd, we would end up with
+a SIGSEGV in nbd_client_put() because we were trying to
+unregister the client's association to the export, even though
+we skipped inserting the client into that list. Easy trigger
+in two terminals:
+
+$ qemu-nbd -p 30001 --format=raw file
+$ nmap 127.0.0.1 -p 30001
+
+nmap claims that it thinks it connected to a pago-services1
+server (which probably means nmap could be updated to learn the
+NBD protocol and give a more accurate diagnosis of the open
+port - but that's not our problem), then terminates immediately,
+so our call to nbd_negotiate() fails. The fix is to reorder
+nbd_co_client_start() to ensure that all initialization occurs
+before we ever try talking to a client in nbd_negotiate(), so
+that the teardown sequence on negotiation failure doesn't fault
+while dereferencing a half-initialized object.
+
+While debugging this, I also noticed that nbd_update_server_watch()
+called by nbd_client_closed() was still adding a channel to accept
+the next client, even when the state was no longer RUNNING. That
+is fixed by making nbd_can_accept() pay attention to the current
+state.
+
+Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1451614
+
+Signed-off-by: Eric Blake <eblake@redhat.com>
+Message-Id: <20170527030421.28366-1-eblake@redhat.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+---
+ nbd/server.c | 8 +++-----
+ qemu-nbd.c | 2 +-
+ 2 files changed, 4 insertions(+), 6 deletions(-)
+
+diff --git a/nbd/server.c b/nbd/server.c
+index ee59e5d234..49b55f6ede 100644
+--- a/nbd/server.c
++++ b/nbd/server.c
+@@ -1358,16 +1358,14 @@ static coroutine_fn void nbd_co_client_start(void *opaque)
+
+ if (exp) {
+ nbd_export_get(exp);
++ QTAILQ_INSERT_TAIL(&exp->clients, client, next);
+ }
++ qemu_co_mutex_init(&client->send_lock);
++
+ if (nbd_negotiate(data)) {
+ client_close(client);
+ goto out;
+ }
+- qemu_co_mutex_init(&client->send_lock);
+-
+- if (exp) {
+- QTAILQ_INSERT_TAIL(&exp->clients, client, next);
+- }
+
+ nbd_client_receive_next_request(client);
+
+diff --git a/qemu-nbd.c b/qemu-nbd.c
+index f60842fd86..651f85ecc1 100644
+--- a/qemu-nbd.c
++++ b/qemu-nbd.c
+@@ -325,7 +325,7 @@ out:
+
+ static int nbd_can_accept(void)
+ {
+- return nb_fds < shared;
++ return state == RUNNING && nb_fds < shared;
+ }
+
+ static void nbd_export_closed(NBDExport *exp)
+--
+2.13.1
+
+From 0c9390d978cbf61e8f16c9f580fa96b305c43568 Mon Sep 17 00:00:00 2001
+From: Eric Blake <eblake@redhat.com>
+Date: Thu, 8 Jun 2017 17:26:17 -0500
+Subject: [PATCH] nbd: Fix regression on resiliency to port scan
+
+Back in qemu 2.5, qemu-nbd was immune to port probes (a transient
+server would not quit, regardless of how many probe connections
+came and went, until a connection actually negotiated). But we
+broke that in commit ee7d7aa when removing the return value to
+nbd_client_new(), although that patch also introduced a bug causing
+an assertion failure on a client that fails negotiation. We then
+made it worse during refactoring in commit 1a6245a (a segfault
+before we could even assert); the (masked) assertion was cleaned
+up in d3780c2 (still in 2.6), and just recently we finally fixed
+the segfault ("nbd: Fully intialize client in case of failed
+negotiation"). But that still means that ever since we added
+TLS support to qemu-nbd, we have been vulnerable to an ill-timed
+port-scan being able to cause a denial of service by taking down
+qemu-nbd before a real client has a chance to connect.
+
+Since negotiation is now handled asynchronously via coroutines,
+we no longer have a synchronous point of return by re-adding a
+return value to nbd_client_new(). So this patch instead wires
+things up to pass the negotiation status through the close_fn
+callback function.
+
+Simple test across two terminals:
+$ qemu-nbd -f raw -p 30001 file
+$ nmap 127.0.0.1 -p 30001 && \
+ qemu-io -c 'r 0 512' -f raw nbd://localhost:30001
+
+Note that this patch does not change what constitutes successful
+negotiation (thus, a client must enter transmission phase before
+that client can be considered as a reason to terminate the server
+when the connection ends). Perhaps we may want to tweak things
+in a later patch to also treat a client that uses NBD_OPT_ABORT
+as being a 'successful' negotiation (the client correctly talked
+the NBD protocol, and informed us it was not going to use our
+export after all), but that's a discussion for another day.
+
+Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1451614
+
+Signed-off-by: Eric Blake <eblake@redhat.com>
+Message-Id: <20170608222617.20376-1-eblake@redhat.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+---
+ blockdev-nbd.c | 6 +++++-
+ include/block/nbd.h | 2 +-
+ nbd/server.c | 24 +++++++++++++++---------
+ qemu-nbd.c | 4 ++--
+ 4 files changed, 23 insertions(+), 13 deletions(-)
+
+diff --git a/blockdev-nbd.c b/blockdev-nbd.c
+index dd0860f4a6..28f551a7b0 100644
+--- a/blockdev-nbd.c
++++ b/blockdev-nbd.c
+@@ -27,6 +27,10 @@ typedef struct NBDServerData {
+
+ static NBDServerData *nbd_server;
+
++static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
++{
++ nbd_client_put(client);
++}
+
+ static gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition,
+ gpointer opaque)
+@@ -46,7 +50,7 @@ static gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition,
+ qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
+ nbd_client_new(NULL, cioc,
+ nbd_server->tlscreds, NULL,
+- nbd_client_put);
++ nbd_blockdev_client_closed);
+ object_unref(OBJECT(cioc));
+ return TRUE;
+ }
+diff --git a/include/block/nbd.h b/include/block/nbd.h
+index 416257abca..8fa5ce51f3 100644
+--- a/include/block/nbd.h
++++ b/include/block/nbd.h
+@@ -162,7 +162,7 @@ void nbd_client_new(NBDExport *exp,
+ QIOChannelSocket *sioc,
+ QCryptoTLSCreds *tlscreds,
+ const char *tlsaclname,
+- void (*close)(NBDClient *));
++ void (*close_fn)(NBDClient *, bool));
+ void nbd_client_get(NBDClient *client);
+ void nbd_client_put(NBDClient *client);
+
+diff --git a/nbd/server.c b/nbd/server.c
+index 49b55f6ede..f2b1aa47ce 100644
+--- a/nbd/server.c
++++ b/nbd/server.c
+@@ -81,7 +81,7 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
+
+ struct NBDClient {
+ int refcount;
+- void (*close)(NBDClient *client);
++ void (*close_fn)(NBDClient *client, bool negotiated);
+
+ bool no_zeroes;
+ NBDExport *exp;
+@@ -778,7 +778,7 @@ void nbd_client_put(NBDClient *client)
+ }
+ }
+
+-static void client_close(NBDClient *client)
++static void client_close(NBDClient *client, bool negotiated)
+ {
+ if (client->closing) {
+ return;
+@@ -793,8 +793,8 @@ static void client_close(NBDClient *client)
+ NULL);
+
+ /* Also tell the client, so that they release their reference. */
+- if (client->close) {
+- client->close(client);
++ if (client->close_fn) {
++ client->close_fn(client, negotiated);
+ }
+ }
+
+@@ -975,7 +975,7 @@ void nbd_export_close(NBDExport *exp)
+
+ nbd_export_get(exp);
+ QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
+- client_close(client);
++ client_close(client, true);
+ }
+ nbd_export_set_name(exp, NULL);
+ nbd_export_set_description(exp, NULL);
+@@ -1337,7 +1337,7 @@ done:
+
+ out:
+ nbd_request_put(req);
+- client_close(client);
++ client_close(client, true);
+ nbd_client_put(client);
+ }
+
+@@ -1363,7 +1363,7 @@ static coroutine_fn void nbd_co_client_start(void *opaque)
+ qemu_co_mutex_init(&client->send_lock);
+
+ if (nbd_negotiate(data)) {
+- client_close(client);
++ client_close(client, false);
+ goto out;
+ }
+
+@@ -1373,11 +1373,17 @@ out:
+ g_free(data);
+ }
+
++/*
++ * Create a new client listener on the given export @exp, using the
++ * given channel @sioc. Begin servicing it in a coroutine. When the
++ * connection closes, call @close_fn with an indication of whether the
++ * client completed negotiation.
++ */
+ void nbd_client_new(NBDExport *exp,
+ QIOChannelSocket *sioc,
+ QCryptoTLSCreds *tlscreds,
+ const char *tlsaclname,
+- void (*close_fn)(NBDClient *))
++ void (*close_fn)(NBDClient *, bool))
+ {
+ NBDClient *client;
+ NBDClientNewData *data = g_new(NBDClientNewData, 1);
+@@ -1394,7 +1400,7 @@ void nbd_client_new(NBDExport *exp,
+ object_ref(OBJECT(client->sioc));
+ client->ioc = QIO_CHANNEL(sioc);
+ object_ref(OBJECT(client->ioc));
+- client->close = close_fn;
++ client->close_fn = close_fn;
+
+ data->client = client;
+ data->co = qemu_coroutine_create(nbd_co_client_start, data);
+diff --git a/qemu-nbd.c b/qemu-nbd.c
+index 651f85ecc1..9464a0461c 100644
+--- a/qemu-nbd.c
++++ b/qemu-nbd.c
+@@ -336,10 +336,10 @@ static void nbd_export_closed(NBDExport *exp)
+
+ static void nbd_update_server_watch(void);
+
+-static void nbd_client_closed(NBDClient *client)
++static void nbd_client_closed(NBDClient *client, bool negotiated)
+ {
+ nb_fds--;
+- if (nb_fds == 0 && !persistent && state == RUNNING) {
++ if (negotiated && nb_fds == 0 && !persistent && state == RUNNING) {
+ state = TERMINATE;
+ }
+ nbd_update_server_watch();
+--
+2.13.1
+
generated by cgit v1.2.3 (git 2.45.0) at 2024-12-01 01:38:31 +0000