CVE-2019-11840

jdstrand

snapd contains an embedded copy of golang-go.crypto with the affected code snapd doesn't import/use the salsa code directly, but does vendor golang-gopkg-macaroon.v1, which imports golang.org/x/crypto/nacl/secretbox which does import salsa and contains the affected salsa2020XORKeyStream. snapd uses secretbox.Open() and secretbox.Seal(), both of which use salsa.XORKeyStream() (which wraps salsa2020XORKeyStream) via the internal decrypt() and encrypt() functions, respectively. In macaroon.v1, encrypt() is only used via AddThirdPartyCaveat() and decrypt() via Verify(). . overlord/auth/auth.go in snapd uses Verify() in CheckMacaroon(), daemon/api.go uses CheckMacaroon() in UserFromRequest(), which is called by ServeHTTP(), the service used to process snap commands from the local system to the local snapd. This CVE does not affect decrypt() operations. . AddThirdPartyCaveat() is only used in unit tests, but not in the binaries of snapd builds. . For snapd, ignoring since only encryption operations (ie, secretbox.Seal()) are affected with regard to loss of confidentiality/predictability and this function is only ever (ultimately) called via the snapd unit tests. lxd contains an embedded copy of golang-go.crypto, but does not import golang.org/x/crypto/nacl/secretbox or salsa. lxd in cosmic and later does not contain the affected code.