ssh signing: support non ssh-* keytypes
The user.signingKey config for ssh signing supports either a path to a
file containing the key or for the sake of convenience a literal string
with the ssh public key. To differentiate between those two cases we
check if the first few characters contain "ssh-" which is unlikely to be
the start of a path. ssh supports other key types which are not prefixed
with "ssh-" and will currently be treated as a file path and therefore
fail to load. To remedy this we move the prefix check into its own
function and introduce the prefix `key::` for literal ssh keys. This way
we don't need to add new key types when they become available. The
existing `ssh-` prefix is retained for compatibility with current user
configs but removed from the official documentation to discourage its
use.
Signed-off-by: Fabian Stelzer <fs@gigacodes.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/gpg-interface.c b/gpg-interface.c
index 3e7255a..73554ea 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -707,6 +707,21 @@ int git_gpg_config(const char *var, const char *value, void *cb)
return 0;
}
+/*
+ * Returns 1 if `string` contains a literal ssh key, 0 otherwise
+ * `key` will be set to the start of the actual key if a prefix is present.
+ */
+static int is_literal_ssh_key(const char *string, const char **key)
+{
+ if (skip_prefix(string, "key::", key))
+ return 1;
+ if (starts_with(string, "ssh-")) {
+ *key = string;
+ return 1;
+ }
+ return 0;
+}
+
static char *get_ssh_key_fingerprint(const char *signing_key)
{
struct child_process ssh_keygen = CHILD_PROCESS_INIT;
@@ -714,15 +729,16 @@ static char *get_ssh_key_fingerprint(const char *signing_key)
struct strbuf fingerprint_stdout = STRBUF_INIT;
struct strbuf **fingerprint;
char *fingerprint_ret;
+ const char *literal_key = NULL;
/*
* With SSH Signing this can contain a filename or a public key
* For textual representation we usually want a fingerprint
*/
- if (starts_with(signing_key, "ssh-")) {
+ if (is_literal_ssh_key(signing_key, &literal_key)) {
strvec_pushl(&ssh_keygen.args, "ssh-keygen", "-lf", "-", NULL);
- ret = pipe_command(&ssh_keygen, signing_key,
- strlen(signing_key), &fingerprint_stdout, 0,
+ ret = pipe_command(&ssh_keygen, literal_key,
+ strlen(literal_key), &fingerprint_stdout, 0,
NULL, 0);
} else {
strvec_pushl(&ssh_keygen.args, "ssh-keygen", "-lf",
@@ -757,6 +773,7 @@ static const char *get_default_ssh_signing_key(void)
const char **argv;
int n;
char *default_key = NULL;
+ const char *literal_key = NULL;
if (!ssh_default_key_command)
die(_("either user.signingkey or gpg.ssh.defaultKeyCommand needs to be configured"));
@@ -774,7 +791,11 @@ static const char *get_default_ssh_signing_key(void)
if (!ret) {
keys = strbuf_split_max(&key_stdout, '\n', 2);
- if (keys[0] && starts_with(keys[0]->buf, "ssh-")) {
+ if (keys[0] && is_literal_ssh_key(keys[0]->buf, &literal_key)) {
+ /*
+ * We only use `is_literal_ssh_key` here to check validity
+ * The prefix will be stripped when the key is used.
+ */
default_key = strbuf_detach(keys[0], NULL);
} else {
warning(_("gpg.ssh.defaultKeyCommand succeeded but returned no keys: %s %s"),
@@ -889,19 +910,20 @@ static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature,
struct tempfile *key_file = NULL, *buffer_file = NULL;
char *ssh_signing_key_file = NULL;
struct strbuf ssh_signature_filename = STRBUF_INIT;
+ const char *literal_key = NULL;
if (!signing_key || signing_key[0] == '\0')
return error(
_("user.signingkey needs to be set for ssh signing"));
- if (starts_with(signing_key, "ssh-")) {
+ if (is_literal_ssh_key(signing_key, &literal_key)) {
/* A literal ssh key */
key_file = mks_tempfile_t(".git_signing_key_tmpXXXXXX");
if (!key_file)
return error_errno(
_("could not create temporary file"));
- keylen = strlen(signing_key);
- if (write_in_full(key_file->fd, signing_key, keylen) < 0 ||
+ keylen = strlen(literal_key);
+ if (write_in_full(key_file->fd, literal_key, keylen) < 0 ||
close_tempfile_gently(key_file) < 0) {
error_errno(_("failed writing ssh signing key to '%s'"),
key_file->filename.buf);
