sslutil: issue warning when [hostfingerprint] is used
Mercurial 3.9 added the [hostsecurity] section, which is better
than [hostfingerprints] in every way.
One of the ways that [hostsecurity] is better is that it supports
SHA-256 and SHA-512 fingerprints, not just SHA-1 fingerprints.
The world is moving away from SHA-1 because it is borderline
secure. Mercurial should be part of that movement.
This patch adds a warning when a valid SHA-1 fingerprint from
the [hostfingerprints] section is being used. The warning informs
users to switch to [hostsecurity]. It even prints the config
option they should set. It uses the SHA-256 fingerprint because
recommending a SHA-1 fingerprint in 2017 would be ill-advised.
The warning will print itself on every connection to a server until
it is fixed. There is no way to suppress the warning. I admit this
is annoying. But given the security implications of sticking with
SHA-1, I think this is justified. If this patch is accepted,
I'll likely send a follow-up to start warning on SHA-1
certificates in [hostsecurity] as well. Then sometime down
the road, we can drop support for SHA-1 fingerprints.
Credit for this idea comes from timeless in issue 5466.
#require gpg
Test the GPG extension
$ cat <<EOF >> $HGRCPATH
> [extensions]
> gpg=
>
> [gpg]
> cmd=gpg --no-permission-warning --no-secmem-warning --no-auto-check-trustdb
> EOF
$ GNUPGHOME="$TESTTMP/gpg"; export GNUPGHOME
$ cp -R "$TESTDIR/gpg" "$GNUPGHOME"
Start gpg-agent, which is required by GnuPG v2
#if gpg21
$ gpg-connect-agent -q --subst /serverpid '/echo ${get serverpid}' /bye \
> >> $DAEMON_PIDS
#endif
and migrate secret keys
#if gpg2
$ gpg --no-permission-warning --no-secmem-warning --list-secret-keys \
> > /dev/null 2>&1
#endif
$ hg init r
$ cd r
$ echo foo > foo
$ hg ci -Amfoo
adding foo
$ hg sigs
$ HGEDITOR=cat hg sign -e 0
signing 0:e63c23eaa88a
Added signature for changeset e63c23eaa88a
HG: Enter commit message. Lines beginning with 'HG:' are removed.
HG: Leave message empty to abort commit.
HG: --
HG: user: test
HG: branch 'default'
HG: added .hgsigs
$ hg sigs
hgtest 0:e63c23eaa88ae77967edcf4ea194d31167c478b0
$ hg sigcheck 0
e63c23eaa88a is signed by:
hgtest
$ cd ..