Re: segfault on kernel v2.4.0

[Michael Driscoll <fenris@ulf.edgemail.com>]

On Tue, Jan 30, 2001 at 08:04:20PM -0500, Chris Kuklewicz wrote:
> Reboot.  Then lsmod to see there are no crypto modules.  Then modprobe
> or insmod the blowfish module (as root).  Look at the error log, look
> at lsmod.  Did that trigger it?  Now try losteup....

Thanks for the tip.  I found that if "modprobe cipher-blowfish" was
manually performed before the "losetup -e blowfish" then everything would
run fine; I only seem to get the segfault+kernelfault when losetup tries
to modprobe the blowfish cipher automatically.

Here are the cases I tried:

modprobe cipher-blowfish
losetup
=> no problem

modprobe cipher-blowfish
modprobe loop
losetup
=> no problem

modprobe loop
losetup
=> segfault

/* no manual modprobes */
losetup
=> segfault

modprobe cryptoapi
losetup
=> segfault


Also, could the following lines be significant?  This is what I see when
I get the segfault:

Jan 30 18:43:26 diva kernel: loop: enabling 8 loop devices
Jan 30 18:43:26 diva modprobe: modprobe: Can't locate module cipher-blowfish-cbc
Jan 30 18:43:27 diva kernel: cipher-blowfish-cbccipher-blowfish<6>cryptoapi: Registered blowfish-ecb (0)
Jan 30 18:43:27 diva kernel: cryptoapi: Registered blowfish-cbc (65536)
Jan 30 18:43:27 diva kernel: divide error: 0000

Note the corruption in the second and third line (I realize it might be a
harmless race in syslog as well).

And here is what it looks like when I enable the modules "by hand":

Jan 30 18:26:54 diva kernel: loop: enabling 8 loop devices
Jan 30 18:27:16 diva kernel: cryptoapi: Registered blowfish-ecb (0)
Jan 30 18:27:16 diva kernel: cryptoapi: Registered blowfish-cbc (65536)

> Hmmm...I am just a user (kernel 2.2.18).  But I do not think you can
> change encryption in place.  You may have to create a second
> filesystem and copy over the data.

(This is exactly what I meant, creating a new fs and copying everything
from the old to the new)

PS. 2.4.1+patch-int-2.4.0.3 still shows these segfaults.

-- 
Michael Driscoll
fenris@ulf.edgemail.com

Linux-crypto:  cryptography in and on the Linux system
Archive:       http://mail.nl.linux.org/linux-crypto/