check if a kernel page is read-only
From: Valdis.Kletnieks at vt.edu <hidden>
Date: 2016-09-07 16:48:58
On Wed, 07 Sep 2016 15:47:30 +0200, Oscar Salvador said:
You are right regarding security stuff, but was not my will either bypassing memory protections or crashing the system.
Never said that was your intent. The problem is that given that tool, some other person can abuse your module with that intent.
- I write a user program which allocates a buffer, then writes something to it and calls a my module via read/write
OK, I'll bite - how are you hooking the read/write syscalls to code in your module? Via a pseudo-device and a struct *file_ops that points at your code? Oh - while you're at it, make sure your code deals properly with buffers that cross page boundaries (for instance, a 512 byte buffer that starts at 3840 bytes into a 4K page, and ends 256 bytes into the next page - particularly fun if the next page is either non-existent or paged out to swap. There's reasons why the code in copy_(to|from)_user() is ugly... -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 830 bytes Desc: not available Url : http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20160907/9e553dd9/attachment.bin