Solved Linuxlator chroot /compat/linux /bin/bash says stack smash?

G

grandpa

I have been running CUDA with the linuxlator as can be seen in this post for some time now. It has been working really well so I decided to try an upgrade.

After pkg upgrade I get an error when trying to step into the linuxlator. The plan was to step into the linuxlator and upgrade the CUDA stuff.

Code: 
chroot /compat/linux /bin/sh
*** stack smashing detected ***: terminated
Abort trap (core dumped)

I suspect this is a security abort to avoid memory tampering but since I haven't changed the Ubuntu something must have come with the FreeBSD upgrade? Is there a way to make bash trust the FreeBSD again?

The linux in the linuxlator is Ubuntu2204.

Code: 
FreeBSD 15.1-RELEASE-p6 releng/15.1-n283643-95719d8a895b GENERIC amd64

mount
devfs on /dev (devfs)
fdescfs on /dev/fd (fdescfs)
procfs on /proc (procfs, local)
linprocfs on /compat/linux/proc (linprocfs, local)
linsysfs on /compat/linux/sys (linsysfs, local)
devfs on /compat/linux/dev (devfs)
fdescfs on /compat/linux/dev/fd (fdescfs)
tmpfs on /compat/linux/dev/shm (tmpfs, local)

sysctl compat.linux.osrelease
compat.linux.osrelease: 5.15.0

lldb chroot /compat/linux /bin/bash
(lldb) target create "chroot"
Current executable set to '/usr/sbin/chroot' (x86_64).
(lldb) settings set -- target.run-args  "/compat/linux" "/bin/bash"
(lldb) r
Process 3381 launched: '/usr/sbin/chroot' (x86_64)
Process 3381 stopped
* thread #1, name = 'bash', stop reason = exec
    frame #0: 0x0000000801181f30
->  0x801181f30: movq   %rsp, %rdi
    0x801181f33: callq  0x801182ca0
    0x801181f38: movq   %rax, %r12
    0x801181f3b: movl   0x19b97(%rip), %eax
(lldb) c
Process 3381 resuming
*** stack smashing detected ***: terminated
Process 3381 stopped
* thread #1, name = 'bash', stop reason = signal SIGABRT
    frame #0: 0x0000000801296a7c
->  0x801296a7c: movl   %eax, %r13d
    0x801296a7f: negl   %r13d
    0x801296a82: cmpl   $0xfffff000, %eax ; imm = 0xFFFFF000 
    0x801296a87: movl   $0x0, %eax
(lldb)

/grandpa
 
SirDice said:
What did you upgrade? Base OS? Or your ports/packages?


Is kind of ambiguous nowadays, because this might include pkgbase updates.
Click to expand...
I did pkg update && pkg upgrade.

I also did pkg upgrade -r FreeBSD-base to verify that kernel was upgraded and it told me it was already up to date.

cracauer@ said:
Which FreeBSD version is this?
Click to expand...
FreeBSD 15.1-RELEASE-p6 releng/15.1-n283643-95719d8a895b GENERIC amd64

/grandpa
 
Did you change anything before the update? Something that may have activated only after a reboot, which I presume you also did after the upgrade?
 
A freshly updated -current with rl9 linux base works fine here. Of course that is quite different from your stack.
 
SirDice said:
Did you change anything before the update? Something that may have activated only after a reboot, which I presume you also did after the upgrade?
Click to expand...
No changes before upgrade, the machine goes on and off daily.

After the upgrade I upgraded the nvidia drivers from 99 to 104 and the next step would have been to step into the linuxlator to upgrade the cuda stuff.

I guess I could try and rebuild the linuxlator retracing my post and see what happens.

I just got curious since it looks and feels like the stack protection comes from the linux side(?) and since I didn't touch that yet I thought I'd ask.

/grandpa
 
Looks like rebuilding the linux side works. I have a succesful chroot /compat/linux /bin/bash.

I just moved /compat/linux to anoher name, recreated /compat/linux directory and followed the necessary steps from my post. Not quite finished yet but since I made it past the chroot I assume it will work. Closing the thread.

/grandpa
 
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