HTML: Fix XSS vulnerability in description/comments (#4852)

Before this PR, the comment/description content was not HTML escaped when 'parse_description()'
was called with a JSON object lacking the "commandRuns" entry.

Closes issue 4727
This commit is contained in:
Samantaz Fox 2024-08-24 20:49:17 +02:00
commit 2876ee0f9f
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@ -36,7 +36,13 @@ def parse_description(desc, video_id : String) : String?
return "" if content.empty? return "" if content.empty?
commands = desc["commandRuns"]?.try &.as_a commands = desc["commandRuns"]?.try &.as_a
return content if commands.nil? if commands.nil?
# Slightly faster than HTML.escape, as we're only doing one pass on
# the string instead of five for the standard library
return String.build do |str|
copy_string(str, content.each_codepoint, content.size)
end
end
# Not everything is stored in UTF-8 on youtube's side. The SMP codepoints # Not everything is stored in UTF-8 on youtube's side. The SMP codepoints
# (0x10000 and above) are encoded as UTF-16 surrogate pairs, which are # (0x10000 and above) are encoded as UTF-16 surrogate pairs, which are