On Wed, Jan 21 2015, Daniel Kahn Gillmor <dkg at fifthhorseman.net> wrote:
> If i send a message with a text/html part (either it's only text/html, > or all parts are rendered, or it's multipart/alternative with only a > text/html subpart) and that HTML has <img > src="http://example.org/test.png"/> in it, then notmuch will make a > network request for that image. I noticed the same a few days ago and first test to avoid that was (defun open-network-stream (&rest) nil) (but then I tried to send email and that failed ;/) next was M-x debug-on-entry RER open-network-stream RET ... but I don,t remember how to manipulate how that continues. Latest I've been thinking defadvice around open-network-stream which asks whether to proceed to it or just return nil. I'd like to have buffer-local defadvices... ;) .. but there one could probably store original open-network-stream location and then flet (or was it letf) it there... Anyway, if there is better, more robust alternative I am (also) very interested of it... Tomi > > This is a privacy disaster, because it enables an e-mail sender to use > "web bugs" to tell when a given notmuch user has opened their e-mail. > > It's also a bit of a consistency/storage/indexing disaster because it > means that what you see when you open a given message will change > depending on the network environment you're in when you open it. > > It's also potentially a security problem because it means that anyone in > control of the remote server (or the network between you and the remote > server if the image isn't sourced over https) can feed arbitrary data > into whatever emacs image rendering library is being used. (granted, > this is not a unique problem because this can already be done by the > original message sender with a multipart/mixed message, but it's an > additional exposure of attack surface) > > I just raised this on #notmuch, and i don't have the time or the > knowledge to look into it now, but i think the defaults here need to be > to avoid network access entirely unless the user explicitly requests it. > > --dkg > _______________________________________________ > notmuch mailing list > notmuch at notmuchmail.org > http://notmuchmail.org/mailman/listinfo/notmuch
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