Bug #17675: StringIO#each_byte doesn't check for readabilty while iterating

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: DONE

[wyhaines (Kirk Haines)]

Bug #17661 is a failure to check readability on each_byte of an IO, causing a segmentation fault.

StringIO has an independent, but related implementation, and it shares the same flaw in its implementation, where it fails to check for the readability of the StringIO object while iterating over the bytes. Unlike IO, this does not result in a segmentation fault. It does, however, allow the continued reading from an object that has been closed.

require "stringio"

strio = StringIO.new
strio.each_byte do |byte|
  puts byte
  strio.close
end

That code should print the first byte, and then throw an IOError, but instead, it iterates through the entire data buffer for the object, calling the block for each byte, without ever raising an exception.

I have a PR for this which I will submit on Github and link to.
The PR simply inserts an appropriate check into the loop for each_byte.

[wyhaines (Kirk Haines)]

The PR is:

https://github.com/ruby/ruby/pull/4245

[nobu (Nobuyoshi Nakada)]

Please submit to https://github.com/ruby/stringio

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|32a13591e0bb6e96b05452e214f14eda21ee3aa9.

---

[ruby/stringio] Check if closed in loop

[Bug #17675] https://bugs.ruby-lang.org/issues/17675

https://github.com/ruby/stringio/commit/1ed61d0cbc

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN to 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: DONE

Backported into ruby_3_0 at e6fced73e55dda487f026c929d97542cf1832252. Thank you hsbt san.