diff options
| -rw-r--r-- | Documentation/config/gpg.txt | 4 | ||||
| -rw-r--r-- | Documentation/config/user.txt | 5 | ||||
| -rw-r--r-- | gpg-interface.c | 138 |
3 files changed, 137 insertions, 10 deletions
diff --git a/Documentation/config/gpg.txt b/Documentation/config/gpg.txt index d94025c..88531b1 100644 --- a/Documentation/config/gpg.txt +++ b/Documentation/config/gpg.txt @@ -11,13 +11,13 @@ gpg.program:: gpg.format:: Specifies which key format to use when signing with `--gpg-sign`. - Default is "openpgp" and another possible value is "x509". + Default is "openpgp". Other possible values are "x509", "ssh". gpg.<format>.program:: Use this to customize the program used for the signing format you chose. (see `gpg.program` and `gpg.format`) `gpg.program` can still be used as a legacy synonym for `gpg.openpgp.program`. The default - value for `gpg.x509.program` is "gpgsm". + value for `gpg.x509.program` is "gpgsm" and `gpg.ssh.program` is "ssh-keygen". gpg.minTrustLevel:: Specifies a minimum trust level for signature verification. If diff --git a/Documentation/config/user.txt b/Documentation/config/user.txt index 59aec7c..2155128 100644 --- a/Documentation/config/user.txt +++ b/Documentation/config/user.txt @@ -36,3 +36,8 @@ user.signingKey:: commit, you can override the default selection with this variable. This option is passed unchanged to gpg's --local-user parameter, so you may specify a key using any method that gpg supports. + If gpg.format is set to "ssh" this can contain the literal ssh public + key (e.g.: "ssh-rsa XXXXXX identifier") or a file which contains it and + corresponds to the private key used for signing. The private key + needs to be available via ssh-agent. Alternatively it can be set to + a file containing a private key directly. diff --git a/gpg-interface.c b/gpg-interface.c index db54b05..7ca682a 100644 --- a/gpg-interface.c +++ b/gpg-interface.c @@ -41,12 +41,20 @@ static const char *x509_sigs[] = { NULL }; +static const char *ssh_verify_args[] = { NULL }; +static const char *ssh_sigs[] = { + "-----BEGIN SSH SIGNATURE-----", + NULL +}; + static int verify_gpg_signed_buffer(struct signature_check *sigc, struct gpg_format *fmt, const char *payload, size_t payload_size, const char *signature, size_t signature_size); static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, const char *signing_key); +static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature, + const char *signing_key); static struct gpg_format gpg_format[] = { { @@ -65,6 +73,14 @@ static struct gpg_format gpg_format[] = { .verify_signed_buffer = verify_gpg_signed_buffer, .sign_buffer = sign_buffer_gpg, }, + { + .name = "ssh", + .program = "ssh-keygen", + .verify_args = ssh_verify_args, + .sigs = ssh_sigs, + .verify_signed_buffer = NULL, /* TODO */ + .sign_buffer = sign_buffer_ssh + }, }; static struct gpg_format *use_format = &gpg_format[0]; @@ -443,6 +459,9 @@ int git_gpg_config(const char *var, const char *value, void *cb) if (!strcmp(var, "gpg.x509.program")) fmtname = "x509"; + if (!strcmp(var, "gpg.ssh.program")) + fmtname = "ssh"; + if (fmtname) { fmt = get_format_by_name(fmtname); return git_config_string(&fmt->program, var, value); @@ -463,12 +482,30 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig return use_format->sign_buffer(buffer, signature, signing_key); } +/* + * Strip CR from the line endings, in case we are on Windows. + * NEEDSWORK: make it trim only CRs before LFs and rename + */ +static void remove_cr_after(struct strbuf *buffer, size_t offset) +{ + size_t i, j; + + for (i = j = offset; i < buffer->len; i++) { + if (buffer->buf[i] != '\r') { + if (i != j) + buffer->buf[j] = buffer->buf[i]; + j++; + } + } + strbuf_setlen(buffer, j); +} + static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, const char *signing_key) { struct child_process gpg = CHILD_PROCESS_INIT; int ret; - size_t i, j, bottom; + size_t bottom; struct strbuf gpg_status = STRBUF_INIT; strvec_pushl(&gpg.args, @@ -494,13 +531,98 @@ static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, return error(_("gpg failed to sign the data")); /* Strip CR from the line endings, in case we are on Windows. */ - for (i = j = bottom; i < signature->len; i++) - if (signature->buf[i] != '\r') { - if (i != j) - signature->buf[j] = signature->buf[i]; - j++; - } - strbuf_setlen(signature, j); + remove_cr_after(signature, bottom); return 0; } + +static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature, + const char *signing_key) +{ + struct child_process signer = CHILD_PROCESS_INIT; + int ret = -1; + size_t bottom, keylen; + struct strbuf signer_stderr = STRBUF_INIT; + struct tempfile *key_file = NULL, *buffer_file = NULL; + char *ssh_signing_key_file = NULL; + struct strbuf ssh_signature_filename = STRBUF_INIT; + + if (!signing_key || signing_key[0] == '\0') + return error( + _("user.signingkey needs to be set for ssh signing")); + + if (starts_with(signing_key, "ssh-")) { + /* 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 || + close_tempfile_gently(key_file) < 0) { + error_errno(_("failed writing ssh signing key to '%s'"), + key_file->filename.buf); + goto out; + } + ssh_signing_key_file = strbuf_detach(&key_file->filename, NULL); + } else { + /* We assume a file */ + ssh_signing_key_file = expand_user_path(signing_key, 1); + } + + buffer_file = mks_tempfile_t(".git_signing_buffer_tmpXXXXXX"); + if (!buffer_file) { + error_errno(_("could not create temporary file")); + goto out; + } + + if (write_in_full(buffer_file->fd, buffer->buf, buffer->len) < 0 || + close_tempfile_gently(buffer_file) < 0) { + error_errno(_("failed writing ssh signing key buffer to '%s'"), + buffer_file->filename.buf); + goto out; + } + + strvec_pushl(&signer.args, use_format->program, + "-Y", "sign", + "-n", "git", + "-f", ssh_signing_key_file, + buffer_file->filename.buf, + NULL); + + sigchain_push(SIGPIPE, SIG_IGN); + ret = pipe_command(&signer, NULL, 0, NULL, 0, &signer_stderr, 0); + sigchain_pop(SIGPIPE); + + if (ret) { + if (strstr(signer_stderr.buf, "usage:")) + error(_("ssh-keygen -Y sign is needed for ssh signing (available in openssh version 8.2p1+)")); + + error("%s", signer_stderr.buf); + goto out; + } + + bottom = signature->len; + + strbuf_addbuf(&ssh_signature_filename, &buffer_file->filename); + strbuf_addstr(&ssh_signature_filename, ".sig"); + if (strbuf_read_file(signature, ssh_signature_filename.buf, 0) < 0) { + error_errno( + _("failed reading ssh signing data buffer from '%s'"), + ssh_signature_filename.buf); + } + unlink_or_warn(ssh_signature_filename.buf); + + /* Strip CR from the line endings, in case we are on Windows. */ + remove_cr_after(signature, bottom); + +out: + if (key_file) + delete_tempfile(&key_file); + if (buffer_file) + delete_tempfile(&buffer_file); + strbuf_release(&signer_stderr); + strbuf_release(&ssh_signature_filename); + FREE_AND_NULL(ssh_signing_key_file); + return ret; +} |