ssh signing: verify ssh-keygen in test prereq

Do a full ssh signing, find-principals and verify operation in the test
prereq's to make sure ssh-keygen works as expected. Only generating the
keys and verifying its presence is not sufficient in some situations.
One example was ssh-keygen creating unusable ssh keys in cygwin because
of unsafe default permissions for the key files. The other a broken
openssh 8.7 that segfaulted on any find-principals operation. This
extended prereq check avoids future test breakages in case ssh-keygen or
any environment behaviour changes.

Signed-off-by: Fabian Stelzer <fs@gigacodes.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/lib-gpg.sh b/t/lib-gpg.sh
index fc03c8f89bc31490939a32ec8c353dc20d7b945c..3fadfcb306a2dd885e131170b32ab53aa3878028 100644 (file)
--- a/t/lib-gpg.sh
+++ b/t/lib-gpg.sh
@@ -109,34 +109,61 @@ test_lazy_prereq GPGSSH '
        echo $ssh_version | grep -q "find-principals:missing signature file"
        test $? = 0 || exit 1;
 
-       # some broken versions of ssh-keygen segfault on find-principals;
-       # avoid testing with them.
-       ssh-keygen -Y find-principals -f /dev/null -s /dev/null
-       test $? = 139 && exit 1
-
+       # Setup some keys and an allowed signers file
        mkdir -p "${GNUPGHOME}" &&
        chmod 0700 "${GNUPGHOME}" &&
        (setfacl -k "${GNUPGHOME}" 2>/dev/null || true) &&
        ssh-keygen -t ed25519 -N "" -C "git ed25519 key" -f "${GPGSSH_KEY_PRIMARY}" >/dev/null &&
-       echo "\"principal with number 1\" $(cat "${GPGSSH_KEY_PRIMARY}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
        ssh-keygen -t rsa -b 2048 -N "" -C "git rsa2048 key" -f "${GPGSSH_KEY_SECONDARY}" >/dev/null &&
-       echo "\"principal with number 2\" $(cat "${GPGSSH_KEY_SECONDARY}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
        ssh-keygen -t ed25519 -N "${GPGSSH_KEY_PASSPHRASE}" -C "git ed25519 encrypted key" -f "${GPGSSH_KEY_WITH_PASSPHRASE}" >/dev/null &&
-       echo "\"principal with number 3\" $(cat "${GPGSSH_KEY_WITH_PASSPHRASE}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
-       ssh-keygen -t ed25519 -N "" -C "git ed25519 key" -f "${GPGSSH_KEY_UNTRUSTED}" >/dev/null
+       ssh-keygen -t ed25519 -N "" -C "git ed25519 key" -f "${GPGSSH_KEY_UNTRUSTED}" >/dev/null &&
+
+       cat >"${GPGSSH_ALLOWED_SIGNERS}" <<-EOF &&
+       "principal with number 1" $(cat "${GPGSSH_KEY_PRIMARY}.pub")"
+       "principal with number 2" $(cat "${GPGSSH_KEY_SECONDARY}.pub")"
+       "principal with number 3" $(cat "${GPGSSH_KEY_WITH_PASSPHRASE}.pub")"
+       EOF
+
+       # Verify if at least one key and ssh-keygen works as expected
+       echo "testpayload" |
+       ssh-keygen -Y sign -n "git" -f "${GPGSSH_KEY_PRIMARY}" >gpgssh_prereq.sig &&
+       ssh-keygen -Y find-principals -f "${GPGSSH_ALLOWED_SIGNERS}" -s gpgssh_prereq.sig &&
+       echo "testpayload" |
+       ssh-keygen -Y verify -n "git" -f "${GPGSSH_ALLOWED_SIGNERS}" -I "principal with number 1" -s gpgssh_prereq.sig
 '
 
 test_lazy_prereq GPGSSH_VERIFYTIME '
        # Check if ssh-keygen has a verify-time option by passing an invalid date to it
        ssh-keygen -Overify-time=INVALID -Y check-novalidate -s doesnotmatter 2>&1 | grep -q -F "Invalid \"verify-time\"" &&
+
+       # Set up keys with key lifetimes
        ssh-keygen -t ed25519 -N "" -C "timeboxed valid key" -f "${GPGSSH_KEY_TIMEBOXEDVALID}" >/dev/null &&
-       echo "\"timeboxed valid key\" valid-after=\"20050407000000\",valid-before=\"200504100000\" $(cat "${GPGSSH_KEY_TIMEBOXEDVALID}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
+       key_valid=$(cat "${GPGSSH_KEY_TIMEBOXEDVALID}.pub") &&
        ssh-keygen -t ed25519 -N "" -C "timeboxed invalid key" -f "${GPGSSH_KEY_TIMEBOXEDINVALID}" >/dev/null &&
-       echo "\"timeboxed invalid key\" valid-after=\"20050401000000\",valid-before=\"20050402000000\" $(cat "${GPGSSH_KEY_TIMEBOXEDINVALID}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
+       key_invalid=$(cat "${GPGSSH_KEY_TIMEBOXEDINVALID}.pub") &&
        ssh-keygen -t ed25519 -N "" -C "expired key" -f "${GPGSSH_KEY_EXPIRED}" >/dev/null &&
-       echo "\"principal with expired key\" valid-before=\"20000101000000\" $(cat "${GPGSSH_KEY_EXPIRED}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
+       key_expired=$(cat "${GPGSSH_KEY_EXPIRED}.pub") &&
        ssh-keygen -t ed25519 -N "" -C "not yet valid key" -f "${GPGSSH_KEY_NOTYETVALID}" >/dev/null &&
-       echo "\"principal with not yet valid key\" valid-after=\"29990101000000\" $(cat "${GPGSSH_KEY_NOTYETVALID}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}"
+       key_notyetvalid=$(cat "${GPGSSH_KEY_NOTYETVALID}.pub") &&
+
+       # Timestamps outside of test_tick span
+       ts2005a=20050401000000 ts2005b=200504020000 &&
+       # Timestamps within test_tick span
+       ts2005c=20050407000000 ts2005d=200504100000 &&
+       # Definitely not yet valid / expired timestamps
+       ts2000=20000101000000 ts2999=29990101000000 &&
+
+       cat >>"${GPGSSH_ALLOWED_SIGNERS}" <<-EOF &&
+       "timeboxed valid key" valid-after="$ts2005c",valid-before="$ts2005d" $key_valid"
+       "timeboxed invalid key" valid-after="$ts2005a",valid-before="$ts2005b" $key_invalid"
+       "principal with expired key" valid-before="$ts2000" $key_expired"
+       "principal with not yet valid key" valid-after="$ts2999" $key_notyetvalid"
+       EOF
+
+       # and verify ssh-keygen verifies the key lifetime
+       echo "testpayload" |
+       ssh-keygen -Y sign -n "git" -f "${GPGSSH_KEY_EXPIRED}" >gpgssh_verifytime_prereq.sig &&
+       ! (ssh-keygen -Y verify -n "git" -f "${GPGSSH_ALLOWED_SIGNERS}" -I "principal with expired key" -s gpgssh_verifytime_prereq.sig)
 '
 
 sanitize_pgp() {