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earlneo

Contributor

Registered: 2016-10-01

Posts: 36

Legic dump is successful. But hf legic info Segmentation fault

Hi iceman & all,

I can legic dump successful, but have issue with legic info command.

I received following errors - Segmentation fault on Segment 04. The proxymark3 client also terminated due to this error.

I tried on another card which have similar errors at Segment 02.

I haven't test the dump data to another card, but any possibility the dump data have issues?

I have load the data into emulator and start tag emulator without any issue.

What would be the problem with the following errors?

Segment 04
raw header | 0x79 0x79 0x79 0x79
Segment len: 2425,  Flag: 0x7 (valid:1, last:0), WRP: 121, WRC: 07, RD: 0, CRC: 0x79 (fail)         
WRC protected area:   (I 4924 | K 4919| WRC 7)         

row  | data         
-----+------------------------------------------------         
[00] | 79 79 79 79 79 79 79
Remaining write protected area:  (I 4931 | K 4931 | WRC 7 | WRP 121  WRP_LEN 114)         

row  | data         
-----+------------------------------------------------         
[00] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[01] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[02] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[03] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[04] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[05] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[06] | 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79 79
[07] | 79 79
Remaining segment payload:  (I 5045 | K 5045 | Remain LEN 2299)         

row  | data         
-----+------------------------------------------------         
Segmentation fault
root@kali:~/Desktop/proxmark3/client#

Last edited by earlneo (2016-10-19 16:06:54)

iceman

Administrator

Registered: 2013-04-25

Posts: 9,538

Website

Re: Legic dump is successful. But hf legic info Segmentation fault

Which version are you using?   PM3 master or icemanfork?

The PM3 Master has known issues with hf legic decode

Icemanfork has known issues with hf legic sim,   The hf legic info  only reads 22bytes,  it should read and decode all available data. its on my todo-list.

earlneo

Contributor

Registered: 2016-10-01

Posts: 36

Re: Legic dump is successful. But hf legic info Segmentation fault

Icemanfork.

I managed to dump, eload, and sim without any errors.

However i havent restore the data yet to a blank card.

Any command for checking .bin file?

iceman

Administrator

Registered: 2013-04-25

Posts: 9,538

Website

Re: Legic dump is successful. But hf legic info Segmentation fault

you can edit the number of bytes read for "hf legic info"  to match your tag size.  It will then decode the whole tag for you.
like it should.

hf legic sim doesnt work at all still.

hf legic dump and hf legic restore works, so you should be able to write a dump onto a blank tag.

mosci

Contributor

Registered: 2016-01-09

Posts: 94

Website

Re: Legic dump is successful. But hf legic info Segmentation fault

this is simply because the tag is empty

Segment 04
raw header | 0x79 0x79 0x79 0x79
Segment len: 2425,  Flag: 0x7 (valid:1, last:0), WRP: 121, WRC: 07, RD: 0, CRC: 0x79 (fail)

every byte is set to 0x79 (should be the MCC) - which is 0x00 de-obfuscated
so the segment-header say's 'this is a valid segment with a length of 2445 bytes' ...
as far as i Know  legic-prime-tags have a maximum of 1024 bytes capacity
thus the logic of the code try's to read bytes beyond the existing address-space - which seems to produce a segmentation-fault.

if you create at least one valid segment on this tag, it should be readable/dumpable without any problems.
even if the 'valid'-flag is set to '1' on this segment 04 - it's simply not the truth ;-) - that's just coincidence

iceman

Administrator

Registered: 2013-04-25

Posts: 9,538

Website

Re: Legic dump is successful. But hf legic info Segmentation fault

Welcome back @mosci,  I've missed you. 

There is a known issue with icemanfork and hf legic info  It needs to be adjusted to read the whole tag.