[01:14] <SturmFlut> I am building an app for Ubuntu Touch which makes use of an unprivileged ICMP socket. The call    socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP)    works on my phone (Nexus 4, Ubuntu Touch r14, Kernel 3.4.0-5-mako), but returns EACCES on my Desktop (Vivid, Kernel 3.18.0-9-generic). I already checked that the 3.18.0-9-generic kernel contains the necessary code for unprivileged ICMP sockets and there are no AppArmor 
[01:14] <SturmFlut> violations on the Desktop.
[01:14] <SturmFlut> Any ideas?
[01:44] <jjohansen> SturmFlut: first I would check that it works correctly from a privileged user
[01:50] <SturmFlut> jjohansen: I'll build a minimal example in C, all I currently have is a lot of C++ code
[02:13] <SturmFlut> jjohansen: https://github.com/Sturmflut/unprivileged-icmp/ should contain a working example. It fails with errno = 13 (EACCES) after the socket() call on my desktop, and completes successfully on the phone. It also fails with errno = 13 when run as root on the desktop.
[02:15] <SturmFlut> jjohansen: I could compare the source code of the 3.4.0-5-mako kernel with 3.18.0-9-generic and find out if there are any differences regarding unprivileged ICMP
[02:15] <jjohansen> sure
[02:16] <SturmFlut> It is 03:16 AM here in Europe, though ;)
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[10:49] <SturmFlut> I found the solution to my unprivileged ICMP socket problem
[10:50] <SturmFlut> The file /proc/sys/net/ipv4/ping_group_range controls which group id ranges are allowed to create such a socket
[10:50] <SturmFlut> On the phone, the content of the file is "0	2147483647", effectively allowing access to anybody
[10:50] <SturmFlut> On the desktop the content is "1 0", effectively disabling the feature completely
[10:58] <SturmFlut> I think this setting should be consistent across devices, but it has some security implications. Fedora 21 Workstation e.g. also ships with the feature disabled
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[23:44] <aeoril> I am interested in working with the ubuntu community on low level stuff - kernel, modules, vms, etc.  This is a long term goal, and I want to prepare myself properly.  I have a history of doing real-time, embedded programming at my last job in C.  However, I want to read up on operating systems development and was hoping for pointers to good resources to help bring me up to speed.  I am 
[23:44] <aeoril> thinking of buying "Modern Operating Systems" by Tanenbaum version 4, but it is expensive and wanted to make sure this was a wise investment.  Any pointers would be appreciated to prepare me to contribute in this area.
[23:45] <aeoril> Note that I already have Modern Operating Systems v. 3 and found it very good, but it seems version 4 is much more up-to-date and releveant today
[23:48] <aeoril> Note that I have looked at the kernel development wiki for Ubuntu and understand there is a ton of stuff there, but wanted to get into some of the academic side of things to be better prepared overall for this direction