How far back?

How far back?

Posted Dec 4, 2003 12:07 UTC (Thu) by IkeTo (subscriber, #2122)
In reply to: How far back? by ncm
Parent article: The brk() vulnerability

2.2 does not have the special case code for brk(), i.e., do_brk, which tries to speed things up because the end of the text segment is special. In 2.2, do_mmap is used to do brk, and do_mmap do all the checking. I think the kernel developers forget that the ELF-header can be modified to start the program such that the text segment might be at the end of the memory space, so they think that it is not possible to have brk() called in such a way that can extend through the end of the address space---normally, the virtual memory bound checking will stop anything wrong from happening.

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