From cd98c93286a30cc4588dfd02453bec63c2f4acf4 Mon Sep 17 00:00:00 2001 From: Beau Belgrave Date: Tue, 25 Apr 2023 15:51:04 -0700 Subject: tracing/user_events: Ensure write index cannot be negative The write index indicates which event the data is for and accesses a per-file array. The index is passed by user processes during write() calls as the first 4 bytes. Ensure that it cannot be negative by returning -EINVAL to prevent out of bounds accesses. Update ftrace self-test to ensure this occurs properly. Link: https://lkml.kernel.org/r/20230425225107.8525-2-beaub@linux.microsoft.com Fixes: 7f5a08c79df3 ("user_events: Add minimal support for trace_event into ftrace") Reported-by: Doug Cook Signed-off-by: Beau Belgrave Signed-off-by: Steven Rostedt (Google) --- tools/testing/selftests/user_events/ftrace_test.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'tools') diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c index aceafacfb126..91272f9d6fce 100644 --- a/tools/testing/selftests/user_events/ftrace_test.c +++ b/tools/testing/selftests/user_events/ftrace_test.c @@ -296,6 +296,11 @@ TEST_F(user, write_events) { ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 3)); after = trace_bytes(); ASSERT_GT(after, before); + + /* Negative index should fail with EINVAL */ + reg.write_index = -1; + ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3)); + ASSERT_EQ(EINVAL, errno); } TEST_F(user, write_fault) { -- cgit v1.2.3