335584f502
CVE-2017-8309: audio: host memory lekage via capture buffer (bz #1446520) CVE-2017-8379: input: host memory lekage via keyboard events (bz #1446560) CVE-2017-8380: scsi: megasas: out-of-bounds read in megasas_mmio_write (bz #1446578) CVE-2017-7493: 9pfs: guest privilege escalation in virtfs mapped-file mode (bz #1451711) CVE-2017-9503: megasas: null pointer dereference while processing megasas command (bz #1459478) CVE-2017-10806: usb-redirect: stack buffer overflow in debug logging (bz #1468497) CVE-2017-9524: nbd: segfault due to client non-negotiation (bz #1460172) CVE-2017-10664: qemu-nbd: server breaks with SIGPIPE upon client abort (bz #1466192)
78 lines
2.5 KiB
Diff
78 lines
2.5 KiB
Diff
From: Eric Blake <eblake@redhat.com>
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Date: Fri, 26 May 2017 22:04:21 -0500
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Subject: [PATCH] nbd: Fully initialize client in case of failed negotiation
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If a non-NBD client connects to qemu-nbd, we would end up with
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a SIGSEGV in nbd_client_put() because we were trying to
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unregister the client's association to the export, even though
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we skipped inserting the client into that list. Easy trigger
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in two terminals:
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$ qemu-nbd -p 30001 --format=raw file
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$ nmap 127.0.0.1 -p 30001
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nmap claims that it thinks it connected to a pago-services1
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server (which probably means nmap could be updated to learn the
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NBD protocol and give a more accurate diagnosis of the open
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port - but that's not our problem), then terminates immediately,
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so our call to nbd_negotiate() fails. The fix is to reorder
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nbd_co_client_start() to ensure that all initialization occurs
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before we ever try talking to a client in nbd_negotiate(), so
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that the teardown sequence on negotiation failure doesn't fault
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while dereferencing a half-initialized object.
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While debugging this, I also noticed that nbd_update_server_watch()
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called by nbd_client_closed() was still adding a channel to accept
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the next client, even when the state was no longer RUNNING. That
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is fixed by making nbd_can_accept() pay attention to the current
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state.
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Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1451614
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Signed-off-by: Eric Blake <eblake@redhat.com>
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Message-Id: <20170527030421.28366-1-eblake@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit df8ad9f128c15aa0a0ebc7b24e9a22c9775b67af)
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---
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nbd/server.c | 8 +++-----
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qemu-nbd.c | 2 +-
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2 files changed, 4 insertions(+), 6 deletions(-)
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diff --git a/nbd/server.c b/nbd/server.c
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index 924a1fe2db..edfda84d43 100644
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--- a/nbd/server.c
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+++ b/nbd/server.c
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@@ -1376,16 +1376,14 @@ static coroutine_fn void nbd_co_client_start(void *opaque)
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if (exp) {
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nbd_export_get(exp);
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+ QTAILQ_INSERT_TAIL(&exp->clients, client, next);
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}
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+ qemu_co_mutex_init(&client->send_lock);
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+
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if (nbd_negotiate(data)) {
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client_close(client);
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goto out;
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}
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- qemu_co_mutex_init(&client->send_lock);
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-
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- if (exp) {
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- QTAILQ_INSERT_TAIL(&exp->clients, client, next);
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- }
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nbd_client_receive_next_request(client);
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diff --git a/qemu-nbd.c b/qemu-nbd.c
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index e080fb7c75..b44764eb87 100644
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--- a/qemu-nbd.c
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+++ b/qemu-nbd.c
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@@ -324,7 +324,7 @@ out:
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static int nbd_can_accept(void)
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{
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- return nb_fds < shared;
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+ return state == RUNNING && nb_fds < shared;
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}
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static void nbd_export_closed(NBDExport *exp)
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