ltp: Fix hang of cve test cases

Backport a patch to the fix possible hang caused by the case of CVE-2017-17052.

CVE: CVE-2017-17052

(From OE-Core rev: 3bde502f612f17b6ed928b04cf5c4ba9ad54d598)

Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/ltp/ltp/0001-cve-2017-17052-Avoid-unsafe-exits-in-threads.patch

@@ -0,0 +1,64 @@
+From e3a8502d0a4f8a44ddd02ca4b2efc097133fb9f7 Mon Sep 17 00:00:00 2001
+From: Mathias Fiedler <mathias.fiedler@aox-tech.de>
+Date: Fri, 23 Aug 2019 12:46:48 +0200
+Subject: [PATCH] cve-2017-17052: Avoid unsafe exits in threads
+
+According to manpage exit(3) calling exit is not thread-safe.
+And with glibc 2.28 (and probably also with glibc >=2.27) sometimes
+child processes created in fork_thread can get stuck on process exit in
+glibc's __run_exit_handlers trying to acquire some lock which was in
+locked state while the fork was created. This can happen when exit is
+called in mmap_thread concurrently to the fork.
+While the main process will still return with PASSED some of its
+children are left behind.
+
+Comparing the source code with the original program as described in the
+commit 2b7e8665b4ff51c034c55df3cff76518d1a9ee3a of linux kernel >=4.13
+the exits in mmap_thread and fork_thread should not be necessary to
+trigger the original bug.
+
+Therefore those exit calls are removed. The mmap_thread and fork_thread
+should still exit when their corresponding main thread in do_test_fork
+calls exit_group. The remaining exit in do_test_fork will be called in
+the main thread without any concurrent thread in the same process.
+
+Signed-off-by: Mathias Fiedler <mathias.fiedler@aox-tech.de>
+Acked-by: Cyril Hrubis <chrubis@suse.cz>
+Acked-by: Jan Stancek <jstancek@redhat.com>
+
+Upstream-Status: Backport
+[https://github.com/linux-test-project/ltp/commit/9f0b452c1af4bcb54da35711eb3fa77334a350b4]
+
+CVE: CVE-2017-17052
+
+Signed-off-by: He Zhe <zhe.he@windriver.com>
+---
+ testcases/cve/cve-2017-17052.c | 5 -----
+ 1 file changed, 5 deletions(-)
+
+diff --git a/testcases/cve/cve-2017-17052.c b/testcases/cve/cve-2017-17052.c
+index d7da7e919..18cd2a6d7 100644
+--- a/testcases/cve/cve-2017-17052.c
++++ b/testcases/cve/cve-2017-17052.c
+@@ -58,8 +58,6 @@ static void *mmap_thread(void *arg)
+ 	for (;;) {
+ 		SAFE_MMAP(NULL, 0x1000000, PROT_READ,
+ 				MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+-		if (*do_exit)
+-			exit(0);
+ 	}
+ 
+ 	return arg;
+@@ -67,9 +65,6 @@ static void *mmap_thread(void *arg)
+ 
+ static void *fork_thread(void *arg)
+ {
+-	if (*do_exit)
+-		exit(0);
+-
+ 	usleep(rand() % 10000);
+ 	SAFE_FORK();
+ 
+-- 
+2.17.1
+

meta/recipes-extended/ltp/ltp_20190517.bb

@@ -48,6 +48,7 @@ SRC_URI = "git://github.com/linux-test-project/ltp.git \
            file://0001-cve-meltdown.c-Fix-kernel-symbol-finding.patch \
            file://0001-testcases-use-python3-everywhere-to-run-python-scrip.patch \
            file://0001-syscall-rt_sigtimedwait01-Fix-wrong-sigset-length-fo.patch \
+           file://0001-cve-2017-17052-Avoid-unsafe-exits-in-threads.patch \
            "
 
 S = "${WORKDIR}/git"