kprobes: Fix possible use-after-free issue on kprobe registration

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: kprobes: Fix possible use-after-free issue on kprobe registration When unloading a module, its state is changing MODULE_STATE_LIVE -> MODULE_STATE_GOING -> MODULE_STATE_UNFORMED. Each change will take a time. `is_module_text_address()` and `__module_text_address()` works with MODULE_STATE_LIVE and MODULE_STATE_GOING. If we use `is_module_text_address()` and `__module_text_address()` separately, there is a chance that the first one is succeeded but the next one is failed because module->state becomes MODULE_STATE_UNFORMED between those operations. In `check_kprobe_address_safe()`, if the second `__module_text_address()` is failed, that is ignored because it expected a kernel_text address. But it may have failed simply because module->state has been changed to MODULE_STATE_UNFORMED. In this case, arm_kprobe() will try to modify non-exist module text address (use-after-free). To fix this problem, we should not use separated `is_module_text_address()` and `__module_text_address()`, but use only `__module_text_address()` once and do `try_module_get(module)` which is only available with MODULE_STATE_LIVE.

References

• https://git.kernel.org/stable/c/b5808d40093403334d939e2c3c417144d12a6f33
• https://git.kernel.org/stable/c/93eb31e7c3399e326259f2caa17be1e821f5a412
• https://git.kernel.org/stable/c/5062d1f4f07facbdade0f402d9a04a788f52e26d
• https://git.kernel.org/stable/c/2df2dd27066cdba8041e46a64362325626bdfb2e
• https://git.kernel.org/stable/c/62029bc9ff2c17a4e3a2478d83418ec575413808
• https://git.kernel.org/stable/c/d15023fb407337028a654237d8968fefdcf87c2f
• https://git.kernel.org/stable/c/36b57c7d2f8b7de224980f1a284432846ad71ca0
• https://git.kernel.org/stable/c/325f3fb551f8cd672dbbfc4cf58b14f9ee3fc9e8