In src/dhcp-manager/nm-dhcp-manager.c, atoi() is used to convert a string containing the MTU value to an int. atoi() doesn't really do any error checking, so strtol() should be used in its place when appropriate. I saw some other uses on atoi() in the source but some of those seem fine since (I assume) glib is doing some checking when storing TYPE_INT and such, but you may want to change all of those to be consistent.
Created attachment 306295 [details] NetworkManager-0.7.0-strtol.patch
committed to trunk, r3776