OSDev.org

https://wiki.osdev.org/System_Calls mentions, that Linux fails to verify pointers from userland. Can someone explain if that's still (or was ever) true and why exactly did Linux lack such safety checks?

Thanks

angods wrote:https://wiki.osdev.org/System_Calls mentions, that Linux fails to verify pointers from userland. Can someone explain if that's still (or was ever) true and why exactly did Linux lack such safety checks?

Thanks

I don't think that is true. Linux provides access checks and copying to/from user memory:

https://elixir.bootlin.com/linux/v5.14. ... cess.h#L52

thewrongchristian wrote:

angods wrote:https://wiki.osdev.org/System_Calls mentions, that Linux fails to verify pointers from userland. Can someone explain if that's still (or was ever) true and why exactly did Linux lack such safety checks?

Thanks

I don't think that is true. Linux provides access checks and copying to/from user memory:

https://elixir.bootlin.com/linux/v5.14. ... cess.h#L52

Then the osdev page should be corrected

I was getting around to that...

Sorry. I added the wrong sentence, and I also just removed it. I originally got tripped up by the difference between get_user and __get_user. The former verifies the pointer is in range, the latter doesn't.