Change was in 2.6.23 kernel update, lines 18-21 of /etc/sysctl.conf. Suggested vm.mmap_min_addr be changed back to zero for Intrepid, as functionality for non-technical users should be more important the protecting the lower 64kb of memory. The linux kernel has a good track record for security vulnerabilities and vulnerabilities exploiting a dereferenced NULL pointer are rare. This also affects hardware virtualisation.
This was discussed in the LKML (https://kerneltrap.org/mailarchive /linux-kernel/2007/6/5/100078) and it was decided that min_addr=0 should be the default behavior so as not to break user-land by default. Excerpt from /etc/sysctl.conf below: # protect bottom 64k of memory from mmap to prevent NULL-dereference # attacks against potential future kernel security vulnerabilities. # (Added in kernel 2.6.23.) vm.mmap_min_addr = 65536 Suggested change to: # If enabled (set to 65536) will prevent userland from allocating # more memory, which is more secure. However some features will # break including dosemu, wine and hardware virtualisation. vm.mmap_min_addr = 0 Finally I request this bug be moved to the ubuntu kernel, as it affects not only dosemu, but also wine, hardware virtualisation and an unknown number of other userland programs. ** Attachment added: "mmap_min_addr.patch" http://launchpadlibrarian.net/18801004/mmap_min_addr.patch -- dosemu segfaults on startup https://bugs.launchpad.net/bugs/216398 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
