Re: [PATCH] parser: Remove escape from the state transitions

[Eric Snowberg]

> On Oct 9, 2017, at 5:48 AM, Daniel Kiper <address@hidden> wrote:
> 
> On Fri, Oct 06, 2017 at 09:37:54AM -0600, Eric Snowberg wrote:
>>> On Oct 6, 2017, at 8:47 AM, Daniel Kiper <address@hidden> wrote:
>>> On Tue, May 30, 2017 at 04:07:52PM -0600, Eric Snowberg wrote:
>>>> Remove GRUB_PARSER_STATE_ESC with state GRUB_PARSER_STATE_TEXT from
>>>> the list of not allowed characters.
>>> 
>>> Once again, NACK for this patch. I explained why earlier but...
>>> 
>>>> This fixes a problem where a properly escaped comma is in the disk path.
>>>> 
>>>> For example: 
>>>> /address@hidden/address@hidden/LSI,address@hidden/address@hidden:a
>>>> 
>>>> During grub install, the search.fs_uuid is correctly stored in the
>>>> core.img.
>>>> 
>>>> As seen here:
>>>> 
>>>> 001e380: 7365 6172 6368 2e66 735f 7575 6964 2039  search.fs_uuid 9
>>>> 001e390: 6462 6137 6333 362d 6431 6432 2d34 6163  dba7c36-d1d2-4ac
>>>> 001e3a0: 642d 6135 3037 2d30 3634 6132 3462 3538  d-a507-064a24b58
>>>> 001e3b0: 3666 3420 726f 6f74 2069 6565 6531 3237  6f4 root ieee127
>>>> 001e3c0: 352f 2f70 6369 4033 3036 2f70 6369 4031  
>>>> 5//address@hidden/address@hidden
>>>> 001e3d0: 2f4c 5349 5c2c 6d72 7361 7340 302f 6469  /LSI\,address@hidden/di
>>>> 001e3e0: 736b 4030 3a61 200a 7365 7420 7072 6566  address@hidden:a .set 
>>>> pref
>>>> 001e3f0: 6978 3d28 2472 6f6f 7429 272f 6772 7562  ix=($root)'/grub
>>>> 001e400: 3227 0a00 0000 0000 0000 0003 0000 0010  2'..............
>>>> 001e410: 2f67 7275 6232 0000                      /grub2..
>>>> 
>>>> Before this change the following args would be sent to
>>>> grub_cmd_do_search:
>>>> 
>>>> key: 9dba7c36-d1d2-4acd-a507-064a24b586f4
>>>> var: root
>>>> hint: 
>>>> ieee1275//address@hidden/address@hidden/LSI,address@hidden/address@hidden:a
>>> 
>>> ...because hint should be quoted in core.img using double quotes or even 
>>> single quotes...
>>> Or every control char should be escaped. Normal shell rules apply here.
>> 
>> Hints are written during the install into the core.img. Once the system
>> boots, the parser is used to retrieve information from the core.img.
>> Currently the parser will strip double quotes, single quotes and escapes.
>> So I don’t understand how you recommend fixing this then.
> 
> Could you send me or point a script which creates embedded config for you?
> 

There is no script. 

As I explained in the patch.  If your boot device name has a comma, which it 
does with a Megaraid, you can not boot GRUB.

Install as follows:

$ grub-install —force /dev/sda1  

By default it creates a core.img with what I provided in the git comment:

001e380: 7365 6172 6368 2e66 735f 7575 6964 2039  search.fs_uuid 9
001e390: 6462 6137 6333 362d 6431 6432 2d34 6163  dba7c36-d1d2-4ac
001e3a0: 642d 6135 3037 2d30 3634 6132 3462 3538  d-a507-064a24b58
001e3b0: 3666 3420 726f 6f74 2069 6565 6531 3237  6f4 root ieee127
001e3c0: 352f 2f70 6369 4033 3036 2f70 6369 4031  
5//address@hidden/address@hidden
001e3d0: 2f4c 5349 5c2c 6d72 7361 7340 302f 6469  /LSI\,address@hidden/di
001e3e0: 736b 4030 3a61 200a 7365 7420 7072 6566  address@hidden:a .set pref
001e3f0: 6978 3d28 2472 6f6f 7429 272f 6772 7562  ix=($root)'/grub
001e400: 3227 0a00 0000 0000 0000 0003 0000 0010  2'..............
001e410: 2f67 7275 6232 0000                      /grub2..

As you can see, everything is escaped as GRUB expects.

Now during boot, the parser is used.  Without my patch, it will strip the \,.

So it changes the hint from:

ieee1275//address@hidden/address@hidden/LSI,address@hidden/address@hidden:a
to
ieee1275//address@hidden/address@hidden/LSI\,address@hidden/address@hidden:a

Later on, when it tries to use this disk, it incorrectly truncates the device 
name since the comma isn’t escaped and tries to do the grub_disk_open with 
ieee1275//address@hidden/address@hidden/LSI.