UPX pads its output to a 4 byte boundary before it writes the loader
stub, and l_lsize counts from that boundary. The block chain resumed at
the end of the last PT_LOAD extent plus l_lsize, so whenever the
compressed extents ended off a 4 byte boundary it landed 1 to 3 bytes
early, read a misaligned b_info, and stopped. The padding between the
segments was never filled in, the reconstruction ended at that first
hole, and .go.buildinfo in the data segment went with it, so the binary
contributed no packages.
The loader skip now rounds up to 4 before adding l_lsize, which matches
the funpad4 in UPX's own unpacker. The crafted fixture for the tail
extents put its stub straight after the head extent, the layout the bug
assumed, so it now pads the way UPX does.
Signed-off-by: huuyafwww <huuya.yamauchi@3-shake.com>
