user_events: Add self-test for validator boundaries

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.

Link: https://lkml.kernel.org/r/20220118204326.2169-11-beaub@linux.microsoft.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
index 68010fd7b719ae46197461dd4dac9f7f4cd2477b..a80fb5ef61d504946adfbbd74f18eec59bebe32d 100644 (file)
--- 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;