Messages in this thread | | | Date | Tue, 19 Jan 1999 02:55:47 -0600 | From | Michael Elizabeth Chastain <> | Subject | Re: Adding checkpointing API to Linux kernel |
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Hi Alexander,
> And from time to time, security issues regarding ioctls that are not > checking for privileges when they should are found. A central > ioctl-directory is a good place to have privilege information too.
This is much less frequent in 2.1 with the current uaccess.h implementations of copy_from_user, copy_to_user, get_user, put_user. At least on i386, these facilities cannot stomp on kernel memory no matter *what* values the user specifies.
There were some problems around 2.1.77 or so with buggy sound driver code that had lots of __get_user and __put_user.
In fact, I would advise someone who wants to do a security check of the kernel (either a Good Guy or a Bad Guy) to make a list of the unchecked functions in uaccess.h, grep the entire kernel source for these functions, and validate all of the use cases. They should all have explicit constraint checks.
Michael
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