The implementations of streams for bz2 and php://output improperly implemented...

Vulnerability Description

The implementations of streams for bz2 and php://output improperly implemented their readImpl functions, returning -1 consistently. This behavior caused some stream functions, such as stream_get_line, to trigger an out-of-bounds read when operating on such malformed streams. The implementations were updated to return valid values consistently. This affects all supported versions of HHVM (3.30 and 3.27.4 and below).

References

• https://hhvm.com/blog/2019/01/14/hhvm-3.30.2.html
• https://github.com/facebook/hhvm/commit/6e4dd9ec3f14b48170fc45dc9d13a3261765f994