On 08/05/2015 05:14 PM, David Daney wrote:
On 08/05/2015 05:06 PM, Leonid Yegoshin wrote:
On 08/05/2015 04:55 PM, Paul Burton wrote:
As was pointed out last time you posted this, it breaks backwards
compatibility with userland & thus cannot be applied.
Never observed since first version.
In other side, the problem with apps like ssh_keygen is observed in
absence of executable stack protection.
You cannot change the default.
If your ssh_keygen is broken, get a working version.
It is actually any application which requests non-executable stack
protection and needs some emulation BEFORE GLIBC cancels that
non-executable stack protection due to libraries.
If you build all libraries with PT_GNU_STACK 'non-executable' and use
application with the same protection then you can't emulate even a
single instruction - it crashes immediately. So, it is not a bad
application, it is a bad choice for emulation space in past.
I have never had a problem running ssh_keygen (on platforms requiring
emulation).
Create a buildroot FS with PT_GNU_STACK 'non-executable' libraries. Then
run ssh_keygen on CPU without FPU and look.
You also may try to run MIPS R2 Debian on MIPS R6 CPU, and see a
spectacular failure of ssh_keygen (it tries to emulate MIPS R2
instruction before first library is loaded and that fails due to
non-executable stack protection.
- Leonid.
