[Bug 229925] [EXP-RUN] Disallow escaping ordinary characters in regex(3)

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=229925

--- Comment #37 from commit-hook at FreeBSD.org ---
A commit references this bug:

Author: kevans
Date: Wed Jul 29 23:21:57 UTC 2020
New revision: 363679
URL: https://svnweb.freebsd.org/changeset/base/363679

Log:
  regex(3): Interpret many escaped ordinary characters as EESCAPE

  In IEEE 1003.1-2008 [1] and earlier revisions, BRE/ERE grammar allows for
  any character to be escaped, but "ORD_CHAR preceded by an unescaped
  <backslash> character [gives undefined results]".

  Historically, we've interpreted an escaped ordinary character as the
  ordinary character itself. This becomes problematic when some extensions
  give special meanings to an otherwise ordinary character
  (e.g. GNU's \b, \s, \w), meaning we may have two different valid
  interpretations of the same sequence.

  To make this easier to deal with and given that the standard calls this
  undefined, we should throw an error (EESCAPE) if we run into this scenario
  to ease transition into a state where some escaped ordinaries are blessed
  with a special meaning -- it will either error out or have extended
  behavior, rather than have two entirely different versions of undefined
  behavior that leave the consumer of regex(3) guessing as to what behavior
  will be used or leaving them with false impressions.

  This change bumps the symbol version of regcomp to FBSD_1.6 and provides the
  old escape semantics for legacy applications, just in case one has an older
  application that would immediately turn into a pumpkin because of an
  extraneous escape that's embedded or otherwise critical to its operation.

  This is the final piece needed before enhancing libregex with GNU extensions
  and flipping the switch on bsdgrep.

  [1] http://pubs.opengroup.org/onlinepubs/9699919799.2016edition/

  PR:           229925 (exp-run, courtesy of antoine)
  Differential Revision:        https://reviews.freebsd.org/D10510

Changes:
  head/contrib/netbsd-tests/lib/libc/regex/data/meta.in
  head/contrib/netbsd-tests/lib/libc/regex/data/subexp.in
  head/lib/libc/regex/Symbol.map
  head/lib/libc/regex/regcomp.c

-- 
You are receiving this mail because:
You are on the CC list for the bug.