Messages in this thread | | | Date | Wed, 26 Aug 1998 13:59:31 +0200 | From | Martin Mares <> | Subject | Re: copy_from_user() fix |
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> Consider a userland pointer verification library that worked in about > 10 lines of code by passing the pointer in question to a sys_write() > call to /dev/null... but this wouldn't work actually these days due to > how the kernel won't even verify the pointer in this case.
It would probably work on several systems, but all standards I know of say that passing of invalid pointer to syscalls has totally undefined effect. Dirty, unportable, hic sunt leones :))
Anyway, it might be interesting to implement a reliable way how to check address ranges (a syscall or maybe a ioctl on /proc/self/mem?)...
Have a nice fortnight -- Martin `MJ' Mares <mj@ucw.cz> http://atrey.karlin.mff.cuni.cz/~mj/ Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth "A LISP programmer knows value of everything, but cost of nothing."
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