programs that lack PT_PHDR are not properly loaded
This is an upstream of https://smartos.org/bugview/OS-4128 from illumos-joyent
Without this, malicious, broken or fuzzed ELF binaries can be misinterpreted and lead to excessive kernel memory consumption.
From the original Joyent ticket:
Apparently, on some conditions (yet to be determined), Linux (or Ubuntu 14.10 or some version of gcc or something else in the toolchain) will generate a binary that lacks the PT_PHDR program header. According to ELF, this is an optional program header, but our binaries have always had it. When this program header is not found, the system annoyingly stops further loading but otherwise returns success -- practically fating the program to die a horrible death in the linker. These binaries are peculiar but they aren't corrupt; we should be able to accommodate them.