[indiana-discuss] Free (freelist) 1717987020927 pages

[Dennis Clarke]

On Tue, Jul 1, 2008 at 9:40 PM, Mike Gerdts <mgerdts at gmail.com> wrote:
> On Tue, Jul 1, 2008 at 11:53 AM, Dennis Clarke <blastwave at gmail.com> wrote:
>> As a side note, and tangential to this discussion, I have long felt
>> that we need a md5hash database in the system that would prevent this
>> sort of hackery from taking place and making a change to a system
>> state via some hacked up binary. Making a change to the kernel should
>> be a strict no no .. but it is possible.
>
> Excellent idea!
>
> $ elfsign verify /kernel/kmdb/sparcv9/genunix
> elfsign: verification of /kernel/kmdb/sparcv9/genunix passed.

# ls -lap /etc/crypto/certs
total 20
drwxr-xr-x   2 root     sys          512 Apr 16 17:14 ./
drwxr-xr-x   4 root     sys          512 Apr 16 17:48 ../
-rw-r--r--   1 root     sys         1194 Jan 21  2005 CA
-rw-r--r--   2 root     sys         1761 Mar 12 04:12 SUNWObjectCA
-rw-r--r--   1 root     sys         1665 Jan 21  2005 SUNW_SunOS_5.10
-rw-r--r--   1 root     sys         1591 Aug  9  2007 SUNW_SunOS_5.11_Limited
# elfsign verify -v /kernel/kmdb/sparcv9/genunix
elfsign: verification of /kernel/kmdb/sparcv9/genunix passed.
format: rsa_md5_sha1.
signer: CN=SunOS 5.10, OU=Solaris Signed Execution, O=Sun Microsystems Inc.
#

I'm not sure how that works but I can only guess that it does. If I
hack up the kernel with a hex editor I don't see how GRUB ( on x86 )
is going to catch that and stop the boot process.

>
> $ elfdump /kernel/kmdb/sparcv9/genunix
> ...
> Section Header[19]:  sh_name: .SUNW_signature
>    sh_addr:      0                   sh_flags:   [ SHF_EXCLUDE ]
>    sh_size:      0x10e               sh_type:    [ SHT_SUNW_SIGNATURE ]
>    sh_offset:    0xd897e             sh_entsize: 0
>    sh_link:      0                   sh_info:    0
>    sh_addralign: 0x1
> ...
>
> I thought bits were around or coming to only execute those things with
> a valid signature.

could be .. I don't really know

Dennis