Bug #19750: Ruby hangs when parsing Regexp with unterminated unicode "/\u{"

• Status: Closed
• Assignee: jeremyevans0 (Jeremy Evans)
• Target version: -
• ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [arm64-darwin22]
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: DONE

[tompng (tomoya ishida)]

Ruby hangs up for a while and gets failed to allocate memory (NoMemoryError)

$ ruby -e "/\\u{"
ruby: failed to allocate memory (NoMemoryError)

RubyVM::AbstractSyntaxTree.parse "/\\u{"
# => SyntaxError

RubyVM::AbstractSyntaxTree.parse "/\\u{\n"
# => failed to allocate memory (NoMemoryError)

Found in https://github.com/ruby/irb/issues/620

[mame (Yusuke Endoh)]

• Related to Bug #18294: error when parsing regexp comment added

[mame (Yusuke Endoh)]

• Status changed from Open to Assigned
• Assignee set to jeremyevans0 (Jeremy Evans)

According to git bisect, this is since ec3542229b29ec93062e9d90e877ea29d3c19472. @jeremyevans0 (Jeremy Evans) Could you take a look at this issue?

[jeremyevans0 (Jeremy Evans)]

mame (Yusuke Endoh) wrote in #note-2:

According to git bisect, this is since ec3542229b29ec93062e9d90e877ea29d3c19472. @jeremyevans0 (Jeremy Evans) Could you take a look at this issue?

Sure, I'll take a look today.

[jeremyevans0 (Jeremy Evans)]

I submitted a pull request to fix this: https://github.com/ruby/ruby/pull/8003

• Status changed from Assigned to Closed

Applied in changeset git|1bc8838d60ef3fc6812d3b64ed87caaf0ae943d9.

---

Handle unterminated unicode escapes in regexps

This fixes an infinite loop possible after ec3542229b29ec93062e9d90e877ea29d3c19472.
For \u{} escapes in regexps, skip validation in the parser, and rely on the regexp
code to handle validation. This is necessary so that invalid unicode escapes in
comments in extended regexps are allowed.

Fixes [Bug #19750]

Co-authored-by: Nobuyoshi Nakada [e-mail]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN to 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: REQUIRED to 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: DONE

ruby_3_2 3f6187a94797d3c4a7db00563a885e4e613b51cf merged revision(s) 1bc8838d60ef3fc6812d3b64ed87caaf0ae943d9.