Jonathan Fabrizio
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[+] HP LaserJet 1020 with cups (on a raspberry)

Jonathan Fabrizio - 08/11/23

Under linux, you can use foo2zjs to manage your LaserJet 10xx printer. This printer is particular as, when you switch on the printer, the firmware must be uploaded. With foo2zjs, a script is provided to upload the firmware when the device is on. But, with new version of CUPS, you can get some messages like (use dmesg):

[  217.425424] usblp 1-1.4:1.0: usblp0: USB Bidirectional printer dev 5 if 0 alt 0 proto 2 vid 0x03F0 pid 0x2B17
but right after, you get:
[  325.810139] usblp0: removed
and this process fails to upload the firmware and the printer is useless. I will propose a workaround for this problem. I use it on my raspberry (in order to connect my printer to the network, but I think my workaround can be used on many different linux distributions.



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[+] Use recent version of OpenGL on older machines (using soft pipeline)

Jonathan Fabrizio - 13/11/20

It is sometime necessary to develop/to run OpenGL program that requires a recent version of OpenGL on an older machine, with a GPU (or a video driver) that does not support recent enough version of OpenGL. A solution is to use a software graphical pipeline. The OpenGL instructions are then executed by the CPU. The performances are certainly not as efficient as with hardware accelerated pipeline (on the GPU), but it allows at least to use older hardware. The solution we propose here has the advantage that the current configuration is not modified. There is no risk for the configuration.

Il est parfois nécessaire, de développer/exécuter des programmes OpenGL qui nécessite une version d'OpenGL plus récente que celle supportée par le GPU (ou le driver video) de la machine utilisée. Une solution est d'utiliser un pipeline graphique software. Dans ce cas, les instructions d'OpenGL sont exécutées sur le CPU. Les performances ne sont certainement pas comparables aux performances obtenues avec une accélération graphique, mais dans beaucoup de cas, cela permet au moins de faire des tests sur du matériel plus ancien. L'avantage de la solution que l'on propose ici est que l'on ne modifie pas la configuration de la machine. Il n'y a donc aucun risque.



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[+] How to interpret RAW Bayer data from the PiCam HQ

Jonathan Fabrizio - 01/06/20

The picams (V1, V2 and now HQ) are interesting cameras as they are not expensive and provide raw data from the sensor. Recently, a new one has been released, the PiCam HQ, but the official documentation does not provide any information on the internal format. This document, explains how to extract/interpret raw images with this new PiCam HQ. The complete pdf version is accessible here!



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[+] HP LaserJet 1020 connection over network

Jonathan Fabrizio - 09/03/13

I tried to connect my HP LaserJet 1020 over a USB printer server and it does not work. Many people over Internet complain about this difficulty but I found no solution on Internet. After few tests, I found how to make it works. I am very happy (and a bit proud). I want to share my solution to help other people to connect this printer (and I think this solution can work for other printers).

J'ai voulu connecter mon imprimante HP laserJet 1020 à l'aide d'un serveur d'impression USB (plus exactement ma Freebox) et ça n'a pas fonctionné. Après recherches sur internet, j'ai vu que beaucoup de personnes ont essayé mais sans succès. Après quelques tests, j'ai fini par trouver une solution. Je suis vraiment content d'avoir trouvé (fier ?). Je vais essayer de décrire et problème et partager ma solution – si ça peut aider d'autres personnes... Je pense que cette solution est applicable à d'autres modèles similaires.



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[+] Hijack SUDO

Jonathan Fabrizio - 22/06/12

To finish a small serie on sudo vulnerabilities, I show in this post that, with a simple trick, it is possible to hook sudo by taking advantages of bash negligence. It is not really serious - I found this funny and I do not think that it can be a serious threat...



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[+] SUDO vulnerability (2/2)

Jonathan Fabrizio - 27/02/12

In a previous post, I showed how a trojan horse can become root by the use of sudo. According to it's configuration, sudo may ask password only once and does not ask password again for a predefined period of time. Malicious software can became root silently.
To exploit this vulnerability, I wrote a program that invokes silently sudo until sudo does not ask password. To succeed, this program must be launched in the correct terminal before the correct user invokes sudo (or right after). This means, the threat is rather low. I complete here the previous post with (too) simple tricks to increase chance to become root (simply to show that even the threat is low, it must not be neglected). To finish, I give simple advice to prevent you from being attacked by such program...



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[+] SUDO vulnerability (1/2)

Jonathan Fabrizio - 08/01/12

Allowing sudo to avoid asking password for executing admin operation disrupts me a bit. I think it is a vulnerability and I will try to prove it in this post. This is not a big threat as this implies the system has already be corrupted but this should not be neglected: I think a simple program can easily become root with this mechanism. Most of this post has been written after an old long discussion on french ubuntu forum but I hesitated long time to publish it.



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