git format-patch --in-reply-to allows header injection. Intended?

Hi,

I just wanted to ask if the --in-reply-to flag of git format-patch is supposed to write the given string unmodified into the email or whether it ought to perform some check against header injection.

For example, if you pass "--in-reply-to=<msgid>\nTo: <other@example.com"
(notice lack of trailing `>`), then the generated email will actually
contain a
  To: <other@example.com>
header.

(Depending on your shell you might also use "--in-reply-to=`cat`" to get the above working more easily.)

Is this known and working as intended, or undesired?

Thanks! Niklas

Niklas Hambüchen <mail@nh2.me> writes:

While I do not think of a reason to specify such a string to the in-reply-to option (I'd rather edit the output in the editor if I wanted to do anything fancy [*1*]), I do not think there is a reason why you want to add a code to forbid such use, either.

[Footnote]

*1* For that matter, --in-reply-to option itself is superfluous.

On 04/09/14 23:36, Junio C Hamano wrote:

My question was to find out whether I can pass untrusted user input to --in-reply-to and expect that no header beyond "In-Reply-To" and "References" is modified, but your answer makes clear that I cannot.

A possible alternative might have been that git verifies that the input to --in-reply-to matches the format specified RFC2822 (section 3.6.4.).

Thanks!

Niklas Hambüchen <mail@nh2.me> writes:

Ah, in general, anybody who passes unvetted user input to any Git Porcelain deserves what s/he gets, so perhaps you would want to at least make sure that the input is a single line, or something.