[LTP] [PATCH 2/2] security/dirtyc0w: synchronize parent and child
Jan Stancek
jstancek@redhat.com
Wed Oct 4 12:42:43 CEST 2017
Add checkpoint to guarantee that parent doesn't send
signal to child before it sets up signal handler.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
testcases/kernel/security/dirtyc0w/dirtyc0w.c | 14 +++++++++++++-
testcases/kernel/security/dirtyc0w/dirtyc0w_child.c | 3 +++
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/testcases/kernel/security/dirtyc0w/dirtyc0w.c b/testcases/kernel/security/dirtyc0w/dirtyc0w.c
index b8094ba977ab..5658f3233f59 100644
--- a/testcases/kernel/security/dirtyc0w/dirtyc0w.c
+++ b/testcases/kernel/security/dirtyc0w/dirtyc0w.c
@@ -36,6 +36,7 @@
* mm: remove gup_flags FOLL_WRITE games from __get_user_pages()
*/
+#include <errno.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <pthread.h>
@@ -49,6 +50,7 @@
#define FNAME "test"
#define STR "this is not a test\n"
+#define TEST_APP "dirtyc0w_child"
static uid_t nobody_uid;
static gid_t nobody_gid;
@@ -67,6 +69,7 @@ void dirtyc0w_test(void)
{
int i, fd, pid, fail = 0;
char c;
+ char *av[] = {TEST_APP, NULL};
/* Create file */
fd = SAFE_OPEN(FNAME, O_WRONLY|O_CREAT|O_EXCL, 0444);
@@ -78,9 +81,11 @@ void dirtyc0w_test(void)
if (!pid) {
SAFE_SETGID(nobody_gid);
SAFE_SETUID(nobody_uid);
- SAFE_EXECLP("dirtyc0w_child", "dirtyc0w_child", NULL);
+ (void)execve(TEST_APP, av, tst_ipc_envp);
+ tst_brk(TBROK|TERRNO, "execve failed");
}
+ TST_CHECKPOINT_WAIT(0);
for (i = 0; i < 100; i++) {
usleep(10000);
@@ -102,10 +107,17 @@ void dirtyc0w_test(void)
tst_res(TPASS, "Bug not reproduced");
}
+static const char *const resource_files[] = {
+ TEST_APP,
+ NULL,
+};
+
static struct tst_test test = {
.needs_tmpdir = 1,
+ .needs_checkpoints = 1,
.forks_child = 1,
.needs_root = 1,
.setup = setup,
.test_all = dirtyc0w_test,
+ .resource_files = resource_files,
};
diff --git a/testcases/kernel/security/dirtyc0w/dirtyc0w_child.c b/testcases/kernel/security/dirtyc0w/dirtyc0w_child.c
index 49abdd6ba52e..bb93c62cb979 100644
--- a/testcases/kernel/security/dirtyc0w/dirtyc0w_child.c
+++ b/testcases/kernel/security/dirtyc0w/dirtyc0w_child.c
@@ -104,7 +104,10 @@ int main(void)
int fd;
struct stat st;
+ tst_reinit();
+
SAFE_SIGNAL(SIGUSR1, sighandler);
+ TST_CHECKPOINT_WAKE(0);
/* Open it read only and map */
fd = SAFE_OPEN(FNAME, O_RDONLY);
--
1.8.3.1
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