Bug #20595: Corruption of encoding name string

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: REQUIRED

[peterzhu2118 (Peter Zhu)]

GitHub PR: https://github.com/ruby/ruby/pull/11062

enc_set_default_encoding will free the C string if the encoding is nil, but the C string can be used by the encoding name string. This will cause the encoding name string to be corrupted.

Consider the following code:

Encoding.default_internal = Encoding::ASCII_8BIT
names = Encoding.default_internal.names
p names
Encoding.default_internal = nil
p names

It outputs:

["ASCII-8BIT", "BINARY", "internal"]
["ASCII-8BIT", "BINARY", "\x00\x00\x00\x00\x00\x00\x00\x00"]

[peterzhu2118 (Peter Zhu)]

The Ruby 3.3 backport PR is here: https://github.com/ruby/ruby/pull/11063

[peterzhu2118 (Peter Zhu)]

• Status changed from Open to Closed

Applied in changeset git|c6a0d03649c686a537c1f513a1e32205ac6a6512.

---

Fix corruption of encoding name string

[Bug #20595]

enc_set_default_encoding will free the C string if the encoding is nil,
but the C string can be used by the encoding name string. This will cause
the encoding name string to be corrupted.

Consider the following code:

Encoding.default_internal = Encoding::ASCII_8BIT
names = Encoding.default_internal.names
p names
Encoding.default_internal = nil
p names

It outputs:

["ASCII-8BIT", "BINARY", "internal"]
["ASCII-8BIT", "BINARY", "\x00\x00\x00\x00\x00\x00\x00\x00"]

Co-authored-by: Matthew Valentine-House [e-mail]