Mercurial > prosody-modules
view mod_latex/mod_latex.lua @ 4651:8231774f5bfd
mod_cloud_notify_encrypted: Ensure body substring remains valid UTF-8
The `body:sub()` call risks splitting the string in the middle of a
multi-byte UTF-8 sequence. This should have been caught by util.stanza
validation, but that would have caused some havoc, at the very least causing
the notification to not be sent.
There have been no reports of this happening. Likely because this module
isn't widely deployed among users with languages that use many longer UTF-8
sequences.
The util.encodings.utf8.valid() function is O(n) where only the last
sequence really needs to be checked, but it's in C and expected to be fast.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sun, 22 Aug 2021 13:22:59 +0200 |
parents | df8da7e4c2bf |
children |
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local st = require "stanza"; local urlencode = require "net.http".urlencode; local xmlns_xhtmlim = "http://jabber.org/protocol/xhtml-im"; local xmlns_xhtml = "http://www.w3.org/1999/xhtml"; local function replace_latex(data) local origin, stanza = data.origin, data.stanza; local body = stanza:get_child_text("body"); if not body or not body:match("%$%$") then return; end module:log("debug", "Replacing latex..."); local html = st.stanza("html", { xmlns = xmlns_xhtmlim }) :tag("body", { xmlns = xmlns_xhtml }); local in_latex, last_char; for snippet, up_to in body:gmatch("(.-)%$%$()") do last_char = up_to; if in_latex then -- Render latex and add image, next snippet is text in_latex = nil; html:tag("img", { src = "http://www.mathtran.org/cgi-bin/mathtran?D=2;tex="..urlencode(snippet), alt = snippet }):up(); else -- Add text to HTML, next snippet is latex in_latex = true; html:tag("span"):text(snippet):up(); end end if last_char < #body then html:tag("span"):text(body:sub(last_char, #body)):up(); end for n, tag in ipairs(stanza.tags) do module:log("debug", "Tag: %s|%s", tag.attr.xmlns or "", tag.name or ""); if tag.name == "html" and tag.attr.xmlns == xmlns_xhtmlim then stanza.tags[n] = html; for n, child in ipairs(stanza) do if child == tag then stanza[n] = html; end end return; end end stanza[#stanza+1] = html; stanza.tags[#stanza.tags+1] = html; end module:hook("message/bare", replace_latex, 30); module:hook("message/full", replace_latex, 30);