Re: [PATCH] x86/dumpstack: don't dump kernel memory based on usermode RIP

2018-08-28 Thread Kees Cook
On Tue, Aug 28, 2018 at 8:18 AM, Jann Horn wrote: > show_opcodes() is used both for dumping kernel instructions and for dumping > user instructions. If userspace causes #PF by jumping to a kernel address, > show_opcodes() can be reached with regs->ip controlled by the user, > pointing to kernel co

[PATCH] x86/dumpstack: don't dump kernel memory based on usermode RIP

2018-08-28 Thread Jann Horn
show_opcodes() is used both for dumping kernel instructions and for dumping user instructions. If userspace causes #PF by jumping to a kernel address, show_opcodes() can be reached with regs->ip controlled by the user, pointing to kernel code. Make sure that userspace can't trick us into dumping ke