| Message ID | 20230411211709.15018-2-beaub@linux.microsoft.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tracing/user_events: Fixes and improvements for 6.4 | expand |
On Tue, 11 Apr 2023 14:17:07 -0700 Beau Belgrave <beaub@linux.microsoft.com> wrote: > 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. > > Fixes: 7f5a08c79df3 ("user_events: Add minimal support for trace_event into ftrace") > Reported-by: Doug Cook <dcook@linux.microsoft.com> > Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Looks good to me. Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Thanks! > --- > kernel/trace/trace_events_user.c | 3 +++ > tools/testing/selftests/user_events/ftrace_test.c | 5 +++++ > 2 files changed, 8 insertions(+) > > diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c > index cc8c6d8b69b5..e7dff24aa724 100644 > --- a/kernel/trace/trace_events_user.c > +++ b/kernel/trace/trace_events_user.c > @@ -1821,6 +1821,9 @@ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i) > if (unlikely(copy_from_iter(&idx, sizeof(idx), i) != sizeof(idx))) > return -EFAULT; > > + if (idx < 0) > + return -EINVAL; > + > rcu_read_lock_sched(); > > refs = rcu_dereference_sched(info->refs); > 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) { > -- > 2.25.1 >
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index cc8c6d8b69b5..e7dff24aa724 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -1821,6 +1821,9 @@ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i) if (unlikely(copy_from_iter(&idx, sizeof(idx), i) != sizeof(idx))) return -EFAULT; + if (idx < 0) + return -EINVAL; + rcu_read_lock_sched(); refs = rcu_dereference_sched(info->refs); 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) {
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. Fixes: 7f5a08c79df3 ("user_events: Add minimal support for trace_event into ftrace") Reported-by: Doug Cook <dcook@linux.microsoft.com> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> --- kernel/trace/trace_events_user.c | 3 +++ tools/testing/selftests/user_events/ftrace_test.c | 5 +++++ 2 files changed, 8 insertions(+)