Misc¶

__ro_after_init¶

Introduction¶

There is a lot of data in the Linux kernel that is only initialized during the __init phase and is never changed afterwards. Memory marked with __ro_after_init cannot be modified again after the init phase ends.

Attack¶

We can use set_memory_rw(unsigned long addr, int numpages) to modify the permissions of the corresponding pages.

mmap_min_addr¶

mmap_min_addr is used to counter NULL Pointer Dereference. It specifies the lowest virtual memory address that a user process can use through mmap.

References¶

• https://lwn.net/Articles/676145/
• https://lwn.net/Articles/666550/
• https://lore.kernel.org/patchwork/patch/621386/