When parsing a truncated clearsigned message (one that includes the
opening header but no armored data), the existing implementation of
clearsign.Decode() hangs in an infinite loop. This commit changes
Decode() to detect the end of the buffer and return as if no
clearsigned message was found.
Change-Id: Ibc85b29a08d22868470f48fe300bf8fcb4749768
Reviewed-on: https://go-review.googlesource.com/17693
Reviewed-by: Adam Langley <agl@golang.org>
clearsign.Encode currently creates bad signatures for inputs containing
lines that that consist of only whitespace (gpg --verify and
clearsign.Decode both agree the signature is bad).
RFC 4880 section 7.1 says trailing whitespace is removed when generating
the signature. The previous code correctly handled this for the case of
not being at the beginning of the line by buffering the whitespace.
The previous code had incorrect behavior for the case of being at the
beginning of a line. It was only special-casing dashes and newlines,
directly hashing all other characters.
This happened to work for lines that had leading whitespace followed by
non-whitespace characters, since in that case the leading whitespace is
not trailing.
However, this behavior is incorrect for whitespace-only lines: The
previous code would incorrectly add the first whitespace character to
the hash, when instead it should have been dropped.
This commit moves the whitespace check so that it always happens,
regardless of whether we are at the beginning of a line.
This adds a few tests to capture the expected behavior. The last three
tests fail without the included code change.
Change-Id: I17848b8aaad6f7a4cee414d486be236f7edddd0b
Reviewed-on: https://go-review.googlesource.com/13681
Reviewed-by: Adam Langley <agl@golang.org>
Clear signed messages are often seen in email and are formatted so
that the plaintext of the signed message is readable without any
special tools.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5604043
Benjamin Wester
Peter Tseng
Andrew Gerrand
Adam Langley