[PATCH v9 10/12] user_events: Add self-test for validator boundaries

From: Beau Belgrave
Date: Tue Jan 11 2022 - 12:27:36 EST


Tests to ensure validator boundary cases are working correctly within
close and far bounds. Ensures __data_loc and __rel_loc strings are
null terminated and within range. Ensures min size checks work as
expected.

Signed-off-by: Beau Belgrave <beaub@xxxxxxxxxxxxxxxxxxx>
---
.../selftests/user_events/ftrace_test.c | 65 +++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
index 68010fd7b719..a80fb5ef61d5 100644
--- a/tools/testing/selftests/user_events/ftrace_test.c
+++ b/tools/testing/selftests/user_events/ftrace_test.c
@@ -309,6 +309,71 @@ TEST_F(user, write_fault) {
ASSERT_EQ(0, munmap(anon, l));
}

+TEST_F(user, write_validator) {
+ struct user_reg reg = {0};
+ struct iovec io[3];
+ int loc, bytes;
+ char data[8];
+ int before = 0, after = 0;
+
+ reg.size = sizeof(reg);
+ reg.name_args = (__u64)"__test_event __rel_loc char[] data";
+
+ /* Register should work */
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(0, reg.write_index);
+ ASSERT_NE(0, reg.status_index);
+
+ io[0].iov_base = &reg.write_index;
+ io[0].iov_len = sizeof(reg.write_index);
+ io[1].iov_base = &loc;
+ io[1].iov_len = sizeof(loc);
+ io[2].iov_base = data;
+ bytes = snprintf(data, sizeof(data), "Test") + 1;
+ io[2].iov_len = bytes;
+
+ /* Undersized write should fail */
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 1));
+ ASSERT_EQ(EINVAL, errno);
+
+ /* Enable event */
+ self->enable_fd = open(enable_file, O_RDWR);
+ ASSERT_NE(-1, write(self->enable_fd, "1", sizeof("1")))
+
+ /* Full in-bounds write should work */
+ before = trace_bytes();
+ loc = DYN_LOC(0, bytes);
+ ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ after = trace_bytes();
+ ASSERT_GT(after, before);
+
+ /* Out of bounds write should fault (offset way out) */
+ loc = DYN_LOC(1024, bytes);
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ ASSERT_EQ(EFAULT, errno);
+
+ /* Out of bounds write should fault (offset 1 byte out) */
+ loc = DYN_LOC(1, bytes);
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ ASSERT_EQ(EFAULT, errno);
+
+ /* Out of bounds write should fault (size way out) */
+ loc = DYN_LOC(0, bytes + 1024);
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ ASSERT_EQ(EFAULT, errno);
+
+ /* Out of bounds write should fault (size 1 byte out) */
+ loc = DYN_LOC(0, bytes + 1);
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ ASSERT_EQ(EFAULT, errno);
+
+ /* Non-Null should fault */
+ memset(data, 'A', sizeof(data));
+ loc = DYN_LOC(0, bytes);
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ ASSERT_EQ(EFAULT, errno);
+}
+
TEST_F(user, print_fmt) {
int ret;

--
2.17.1