1975 Unix flaw fixed – The INQUIRER

A BUG IN UNIX that has been in existence since 1975 has finally been fixed.

The bug in an AT&T version of Unix, which was undiscovered until recently, has been with us ever since the Who’s Tommy flick premiered in London, the first microcomputer the Altair 8800 hit the shops, and three people were found guilty in the Watergate cover-up

It was spotted by OpenBSD developer Otto Moerbeek and affected the YACC parser generator. This followed a discovery of a 25 year old BSD flaw in May.

Moerbeek found the Unix bug when he was testing a new implementation of malloc, a general-purpose memory allocator. There was a problem with the Sparc64 hardware platform and using the new malloc, compiling large C projects would sometimes fail with an internal compiler error.

He found that the bug was in YACC, a parser generator developed by Stephen Johnson at AT&T which had been a part of Unix since the 1970s.

Johnson’s code worked for so long because the older malloc’s didn’t catch buffer overflows so efficiently. The bug is triggered only on Sparc64 systems