H
Harald Welte
laforge.gnumonks.org · Personal blog · on HN since 2008
Harald Welte, an open source GSM and telecom developer, writes about cellular protocols, baseband security, and GPL enforcement cases.
What HN saysHN links it for GSM and cellular modem details and for firsthand reports on GPL court cases like VMware's.
56HN people shared it
10linked it in comments
76stories submitted
2.5Kstory points
1 year agolast shared
2008people per year2026
Most-shared posts
- 1Report from the VMware GPL court hearing3 people · 201 points · first shared 2016 · 49 comments on HN
- 2A brief history on the withdrawal of the A5/2 ciphering algorithm in GSM3 people · 35 points · first shared 2010 · discussion on HN
- 3Ten years anniversary of Openmoko3 people · 6 points · first shared 2016 · discussion on HN
- 4Why do self-respecting hackers use Gmail & Co?2 people · 235 points · first shared 2011 · 262 comments on HN
- 5HTC's delays in releasing Linux source code are unacceptable2 people · 149 points · first shared 2011 · 25 comments on HN
- 6Worlds first 20 minute voice call from a Free Software GSM stack on a phone2 people · 84 points · first shared 2010 · 10 comments on HN
- 7Report from the Geniatech vs. McHardy GPL violation court hearing2 people · 69 points · first shared 2018 · 23 comments on HN
- 8The sad state of voice support in cellular modems2 people · 68 points · first shared 2017 · 20 comments on HN
- 9Android is a screwed, hard-coded, non-portable abomination.2 people · 25 points · first shared 2009 · 25 comments on HN
- 10Power-cycling a USB port should be simple, right? (2017)2 people · 21 points · first shared 2020 · 15 comments on HN
- 11Harald Welte: Inside a cavity duplexer2 people · 19 points · first shared 2012 · discussion on HN
- 12Student sentenced for detecting flaws in Slovenian police and army TETRA network2 people · 9 points · first shared 2016 · discussion on HN
- 13Sometimes software development is a struggle2 people · 4 points · first shared 2019 · discussion on HN
- 14Developers wanted for Osmocom GSM related work2 people · 4 points · first shared 2016 · discussion on HN
- 15Anatomy of contemporary GSM cellphone hardware [pdf]2 people · 3 points · first shared 2010 · discussion on HN
What HN people wrote when they linked it
tyingq · 2024-01-23
"So far the theory. If you look at the Paging Channel (PCH) of cells in real-world networks, you see a significant (10-20%) amount of paging requests that contain paging by IMSI. This seems strange on first sight, given the theory..."[1]
So you can't spy on everyone, but you can spy on some subscribers whose phone is in that state.
[1] https://laforge.gnumonks.org/blog/20100628-the_reason_for_paging_by_im…
gsich · 2022-08-17
Examples?
https://laforge.gnumonks.org/blog/20170902-cellular_modems-voice/
comes to mind. Regardless of age.
davidgerard · 2016-03-03
> Has anyone ever seen GPL being encorced in any country?
... yes? Lots and lots.
There's a prominent case involving VMware versus Christoph Hellwig on right now: http://laforge.gnumonks.org/blog/20160225-vmware-gpl/
One manufacturer violation ended up with Busybox/SFC awarded a pile of the violating televisions ... http://arstechnica.com/information-technology/2010/08/court-rules-gpl-…
viraptor · 2014-01-26
As much as I'd like to believe that they did mess up the interception reporting (if they really do interception like that), I've seen enough crazy tracking reports that I wouldn't be surprised if it was just a stupid mistake.
Just googling for "funny delivery tracking route" for example will give you things like:
- 4 times over the ocean - http://i696.photobucket.com/albums/vv325/oneupmanship34/Fg0eg.png?t=12…
- let's send it to Canada, 3 times - http://i30.photobucket.com/albums/c325/duffer987/UPSFTD_zps68aae690.jp…
- Germany, HK, Germany, HK, ... - http://laforge.gnumonks.org/fun/dhl-hk-leipzig-hk-leipzig-hk.jpg
Getting a strange route within one country is probably an improvement compared to those...
citrin_ru · 2013-11-19
I doubt it is fully open phone. At least soft, that works on baseband processor probably closed. More about this problem: https://laforge.gnumonks.org/papers/gsm_phone-anatomy-latest.pdf
hosay123 · 2013-01-14
There was quite a lot of dissent about 29c3 primarily because it moved. I think that is also the reason the schedule suffered, so hopefully it's just temporary. Here's Harald Welte discussing why he didn't participate this year: http://laforge.gnumonks.org/weblog/2012/12/18/#20121218-29c3
bryanlarsen · 2011-06-20
This is much more than your typical license violation -- AVM is suing Cybits because Cybits exercised their GPL rights. So this is a very important case to legitimize the GPL.
more information on Harald Welte's blog: http://laforge.gnumonks.org/weblog/2011/06/20/#20110620-avm_cybits_gpl…
mctavjb9 · 2010-08-02
This demonstration is neither particularly novel nor particularly legal.
http://laforge.gnumonks.org/weblog/2010/08/01/#20100801-on_recent_news…
seiji · 2009-12-07
Just because something is available doesn't mean it should be used.
Android actually kinda sucks (second post on page): http://laforge.gnumonks.org/weblog/2009/11/04/
themulticaster · 2021-08-26
In addition to what myself248 said:
In case you aren't familiar with the details of consumer RF standards (including IEEE 802.11, but especially LTE or anything cellular related) or don't have some prior RF knowledge: To put it mildly, LTE is not an easy standard to implement on an SDR, especially if it's your contact with SDRs. Even GSM is nowhere near a simple stack.
If you want to get a feeling for what kind of cellular projects are possible using SDRs from a hobbyist/free software perspective, have a look at the Osmocom (Open Source Mobile Communications) projects [1] as well as Harald Welte's blog [2] (one of the main Osmocom contributors). The Osmocom projects are focused on the carrier side of LTE/GSM networks AFAIK.
Another warning: While cellular technology involves lots of networks, it is completely different from the standards and terminology used in the Internet. For example, citing the description for OsmoHNBGW:
"An Open Source implementation of a HNB-GW (HomeNodeB-Gateway), implementing the Iuh, IuCS and IuPS interfaces. It aggregates the Iuh links from femtocells (hNodeBs) and presents them as regular IuCS and IuPS towards MSC and SGSN (such as OsmoMSC and OsmoSGSN). It uses M3UA as signaling transport."
The description totally makes sense to an insider, but if you only dabbled with TCP/IP, routers and switches so far, be prepared for learning a whole new world of networking terms.
If you are familiar with RF/cellular engineering and/or if you're trying to…