/src/git/credential.c

Source
#define DISABLE_SIGN_COMPARE_WARNINGS

#include "git-compat-util.h"
#include "abspath.h"
#include "config.h"
#include "credential.h"
#include "gettext.h"
#include "string-list.h"
#include "run-command.h"
#include "url.h"
#include "prompt.h"
#include "sigchain.h"
#include "strbuf.h"
#include "urlmatch.h"
#include "environment.h"
#include "trace2.h"
#include "repository.h"

void credential_init(struct credential *c)
{
  struct credential blank = CREDENTIAL_INIT;
  memcpy(c, &blank, sizeof(*c));
}

void credential_clear(struct credential *c)
{
  credential_clear_secrets(c);
  free(c->protocol);
  free(c->host);
  free(c->path);
  free(c->username);
  free(c->oauth_refresh_token);
  free(c->authtype);
  string_list_clear(&c->helpers, 0);
  strvec_clear(&c->wwwauth_headers);
  strvec_clear(&c->state_headers);
  strvec_clear(&c->state_headers_to_send);

  credential_init(c);
}

void credential_next_state(struct credential *c)
{
  strvec_clear(&c->state_headers_to_send);
  SWAP(c->state_headers, c->state_headers_to_send);
}

void credential_clear_secrets(struct credential *c)
{
  FREE_AND_NULL(c->password);
  FREE_AND_NULL(c->credential);
}

static void credential_set_capability(struct credential_capability *capa,
              enum credential_op_type op_type)
{
  switch (op_type) {
  case CREDENTIAL_OP_INITIAL:
    capa->request_initial = 1;
    break;
  case CREDENTIAL_OP_HELPER:
    capa->request_helper = 1;
    break;
  case CREDENTIAL_OP_RESPONSE:
    capa->response = 1;
    break;
  }
}


void credential_set_all_capabilities(struct credential *c,
             enum credential_op_type op_type)
{
  credential_set_capability(&c->capa_authtype, op_type);
  credential_set_capability(&c->capa_state, op_type);
}

static void announce_one(struct credential_capability *cc, const char *name, FILE *fp) {
  if (cc->request_initial)
    fprintf(fp, "capability %s\n", name);
}

void credential_announce_capabilities(struct credential *c, FILE *fp) {
  fprintf(fp, "version 0\n");
  announce_one(&c->capa_authtype, "authtype", fp);
  announce_one(&c->capa_state, "state", fp);
}

int credential_match(const struct credential *want,
         const struct credential *have, int match_password)
{
#define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  return CHECK(protocol) &&
         CHECK(host) &&
         CHECK(path) &&
         CHECK(username) &&
         (!match_password || CHECK(password)) &&
         (!match_password || CHECK(credential));
#undef CHECK
}


static int credential_from_potentially_partial_url(struct credential *c,
               const char *url);

static int credential_config_callback(const char *var, const char *value,
              const struct config_context *ctx UNUSED,
              void *data)
{
  struct credential *c = data;
  const char *key;

  if (!skip_prefix(var, "credential.", &key))
    return 0;

  if (!value)
    return config_error_nonbool(var);

  if (!strcmp(key, "helper")) {
    if (*value)
      string_list_append(&c->helpers, value);
    else
      string_list_clear(&c->helpers, 0);
  } else if (!strcmp(key, "username")) {
    if (!c->username_from_proto) {
      free(c->username);
      c->username = xstrdup(value);
    }
  }
  else if (!strcmp(key, "usehttppath"))
    c->use_http_path = git_config_bool(var, value);
  else if (!strcmp(key, "sanitizeprompt"))
    c->sanitize_prompt = git_config_bool(var, value);
  else if (!strcmp(key, "protectprotocol"))
    c->protect_protocol = git_config_bool(var, value);

  return 0;
}

static int proto_is_http(const char *s)
{
  if (!s)
    return 0;
  return !strcmp(s, "https") || !strcmp(s, "http");
}

static void credential_describe(struct credential *c, struct strbuf *out);
static void credential_format(struct credential *c, struct strbuf *out);

static int select_all(const struct urlmatch_item *a UNUSED,
          const struct urlmatch_item *b UNUSED)
{
  return 0;
}

static int match_partial_url(const char *url, void *cb)
{
  struct credential *c = cb;
  struct credential want = CREDENTIAL_INIT;
  int matches = 0;

  if (credential_from_potentially_partial_url(&want, url) < 0)
    warning(_("skipping credential lookup for key: credential.%s"),
      url);
  else
    matches = credential_match(&want, c, 0);
  credential_clear(&want);

  return matches;
}

static void credential_apply_config(struct repository *r, struct credential *c)
{
  char *normalized_url;
  struct urlmatch_config config = URLMATCH_CONFIG_INIT;
  struct strbuf url = STRBUF_INIT;

  if (!c->host)
    die(_("refusing to work with credential missing host field"));
  if (!c->protocol)
    die(_("refusing to work with credential missing protocol field"));

  if (c->configured)
    return;

  config.section = "credential";
  config.key = NULL;
  config.collect_fn = credential_config_callback;
  config.cascade_fn = NULL;
  config.select_fn = select_all;
  config.fallback_match_fn = match_partial_url;
  config.cb = c;

  credential_format(c, &url);
  normalized_url = url_normalize(url.buf, &config.url);

  repo_config(r, urlmatch_config_entry, &config);
  string_list_clear(&config.vars, 1);
  free(normalized_url);
  urlmatch_config_release(&config);
  strbuf_release(&url);

  c->configured = 1;

  if (!c->use_http_path && proto_is_http(c->protocol)) {
    FREE_AND_NULL(c->path);
  }
}

static void credential_describe(struct credential *c, struct strbuf *out)
{
  if (!c->protocol)
    return;
  strbuf_addf(out, "%s://", c->protocol);
  if (c->username && *c->username)
    strbuf_addf(out, "%s@", c->username);
  if (c->host)
    strbuf_addstr(out, c->host);
  if (c->path)
    strbuf_addf(out, "/%s", c->path);
}

static void credential_format(struct credential *c, struct strbuf *out)
{
  if (!c->protocol)
    return;
  strbuf_addf(out, "%s://", c->protocol);
  if (c->username && *c->username) {
    strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
    strbuf_addch(out, '@');
  }
  if (c->host)
    strbuf_add_percentencode(out, c->host,
           STRBUF_ENCODE_HOST_AND_PORT);
  if (c->path) {
    strbuf_addch(out, '/');
    strbuf_add_percentencode(out, c->path, 0);
  }
}

static char *credential_ask_one(const char *what, struct credential *c,
        int flags)
{
  struct strbuf desc = STRBUF_INIT;
  struct strbuf prompt = STRBUF_INIT;
  char *r;

  if (c->sanitize_prompt)
    credential_format(c, &desc);
  else
    credential_describe(c, &desc);
  if (desc.len)
    strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
  else
    strbuf_addf(&prompt, "%s: ", what);

  r = git_prompt(prompt.buf, flags);

  strbuf_release(&desc);
  strbuf_release(&prompt);
  return xstrdup(r);
}

static int credential_getpass(struct repository *r, struct credential *c)
{
  int interactive;
  char *value;
  if (!repo_config_get_maybe_bool(r, "credential.interactive", &interactive) &&
      !interactive) {
    trace2_data_intmax("credential", r,
           "interactive/skipped", 1);
    return -1;
  }
  if (!repo_config_get_string(r, "credential.interactive", &value)) {
    int same = !strcmp(value, "never");
    free(value);
    if (same) {
      trace2_data_intmax("credential", r,
             "interactive/skipped", 1);
      return -1;
    }
  }

  trace2_region_enter("credential", "interactive", r);
  if (!c->username)
    c->username = credential_ask_one("Username", c,
             PROMPT_ASKPASS|PROMPT_ECHO);
  if (!c->password)
    c->password = credential_ask_one("Password", c,
             PROMPT_ASKPASS);
  trace2_region_leave("credential", "interactive", r);

  return 0;
}

int credential_has_capability(const struct credential_capability *capa,
            enum credential_op_type op_type)
{
  /*
   * We're checking here if each previous step indicated that we had the
   * capability.  If it did, then we want to pass it along; conversely, if
   * it did not, we don't want to report that to our caller.
   */
  switch (op_type) {
  case CREDENTIAL_OP_HELPER:
    return capa->request_initial;
  case CREDENTIAL_OP_RESPONSE:
    return capa->request_initial && capa->request_helper;
  default:
    return 0;
  }
}

int credential_read(struct credential *c, FILE *fp,
        enum credential_op_type op_type)
{
  struct strbuf line = STRBUF_INIT;

  while (strbuf_getline(&line, fp) != EOF) {
    char *key = line.buf;
    char *value = strchr(key, '=');

    if (!line.len)
      break;

    if (!value) {
      warning("invalid credential line: %s", key);
      strbuf_release(&line);
      return -1;
    }
    *value++ = '\0';

    if (!strcmp(key, "username")) {
      free(c->username);
      c->username = xstrdup(value);
      c->username_from_proto = 1;
    } else if (!strcmp(key, "password")) {
      free(c->password);
      c->password = xstrdup(value);
    } else if (!strcmp(key, "credential")) {
      free(c->credential);
      c->credential = xstrdup(value);
    } else if (!strcmp(key, "protocol")) {
      free(c->protocol);
      c->protocol = xstrdup(value);
    } else if (!strcmp(key, "host")) {
      free(c->host);
      c->host = xstrdup(value);
    } else if (!strcmp(key, "path")) {
      free(c->path);
      c->path = xstrdup(value);
    } else if (!strcmp(key, "ephemeral")) {
      c->ephemeral = !!git_config_bool("ephemeral", value);
    } else if (!strcmp(key, "wwwauth[]")) {
      strvec_push(&c->wwwauth_headers, value);
    } else if (!strcmp(key, "state[]")) {
      strvec_push(&c->state_headers, value);
    } else if (!strcmp(key, "capability[]")) {
      if (!strcmp(value, "authtype"))
        credential_set_capability(&c->capa_authtype, op_type);
      else if (!strcmp(value, "state"))
        credential_set_capability(&c->capa_state, op_type);
    } else if (!strcmp(key, "continue")) {
      c->multistage = !!git_config_bool("continue", value);
    } else if (!strcmp(key, "password_expiry_utc")) {
      errno = 0;
      c->password_expiry_utc = parse_timestamp(value, NULL, 10);
      if (c->password_expiry_utc == 0 || errno == ERANGE)
        c->password_expiry_utc = TIME_MAX;
    } else if (!strcmp(key, "oauth_refresh_token")) {
      free(c->oauth_refresh_token);
      c->oauth_refresh_token = xstrdup(value);
    } else if (!strcmp(key, "authtype")) {
      free(c->authtype);
      c->authtype = xstrdup(value);
    } else if (!strcmp(key, "url")) {
      credential_from_url(c, value);
    } else if (!strcmp(key, "quit")) {
      c->quit = !!git_config_bool("quit", value);
    }
    /*
     * Ignore other lines; we don't know what they mean, but
     * this future-proofs us when later versions of git do
     * learn new lines, and the helpers are updated to match.
     */
  }

  strbuf_release(&line);
  return 0;
}

static void credential_write_item(const struct credential *c,
          FILE *fp, const char *key, const char *value,
          int required)
{
  if (!value && required)
    BUG("credential value for %s is missing", key);
  if (!value)
    return;
  if (strchr(value, '\n'))
    die("credential value for %s contains newline", key);
  if (c->protect_protocol && strchr(value, '\r'))
    die("credential value for %s contains carriage return\n"
        "If this is intended, set `credential.protectProtocol=false`",
        key);
  fprintf(fp, "%s=%s\n", key, value);
}

void credential_write(const struct credential *c, FILE *fp,
          enum credential_op_type op_type)
{
  if (credential_has_capability(&c->capa_authtype, op_type))
    credential_write_item(c, fp, "capability[]", "authtype", 0);
  if (credential_has_capability(&c->capa_state, op_type))
    credential_write_item(c, fp, "capability[]", "state", 0);

  if (credential_has_capability(&c->capa_authtype, op_type)) {
    credential_write_item(c, fp, "authtype", c->authtype, 0);
    credential_write_item(c, fp, "credential", c->credential, 0);
    if (c->ephemeral)
      credential_write_item(c, fp, "ephemeral", "1", 0);
  }
  credential_write_item(c, fp, "protocol", c->protocol, 1);
  credential_write_item(c, fp, "host", c->host, 1);
  credential_write_item(c, fp, "path", c->path, 0);
  credential_write_item(c, fp, "username", c->username, 0);
  credential_write_item(c, fp, "password", c->password, 0);
  credential_write_item(c, fp, "oauth_refresh_token", c->oauth_refresh_token, 0);
  if (c->password_expiry_utc != TIME_MAX) {
    char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
    credential_write_item(c, fp, "password_expiry_utc", s, 0);
    free(s);
  }
  for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
    credential_write_item(c, fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
  if (credential_has_capability(&c->capa_state, op_type)) {
    if (c->multistage)
      credential_write_item(c, fp, "continue", "1", 0);
    for (size_t i = 0; i < c->state_headers_to_send.nr; i++)
      credential_write_item(c, fp, "state[]", c->state_headers_to_send.v[i], 0);
  }
}

static int run_credential_helper(struct credential *c,
         const char *cmd,
         int want_output)
{
  struct child_process helper = CHILD_PROCESS_INIT;
  FILE *fp;

  strvec_push(&helper.args, cmd);
  helper.use_shell = 1;
  helper.in = -1;
  if (want_output)
    helper.out = -1;
  else
    helper.no_stdout = 1;

  if (start_command(&helper) < 0)
    return -1;

  fp = xfdopen(helper.in, "w");
  sigchain_push(SIGPIPE, SIG_IGN);
  credential_write(c, fp, want_output ? CREDENTIAL_OP_HELPER : CREDENTIAL_OP_RESPONSE);
  fclose(fp);
  sigchain_pop(SIGPIPE);

  if (want_output) {
    int r;
    fp = xfdopen(helper.out, "r");
    r = credential_read(c, fp, CREDENTIAL_OP_HELPER);
    fclose(fp);
    if (r < 0) {
      finish_command(&helper);
      return -1;
    }
  }

  if (finish_command(&helper))
    return -1;
  return 0;
}

static int credential_do(struct credential *c, const char *helper,
       const char *operation)
{
  struct strbuf cmd = STRBUF_INIT;
  int r;

  if (helper[0] == '!')
    strbuf_addstr(&cmd, helper + 1);
  else if (is_absolute_path(helper))
    strbuf_addstr(&cmd, helper);
  else
    strbuf_addf(&cmd, "git credential-%s", helper);

  strbuf_addf(&cmd, " %s", operation);
  r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));

  strbuf_release(&cmd);
  return r;
}

void credential_fill(struct repository *r,
         struct credential *c, int all_capabilities)
{
  int i;

  if ((c->username && c->password) || c->credential)
    return;

  credential_next_state(c);
  c->multistage = 0;

  credential_apply_config(r, c);
  if (all_capabilities)
    credential_set_all_capabilities(c, CREDENTIAL_OP_INITIAL);

  for (i = 0; i < c->helpers.nr; i++) {
    credential_do(c, c->helpers.items[i].string, "get");

    if (c->password_expiry_utc < time(NULL)) {
      /*
       * Don't use credential_clear() here: callers such as
       * cmd_credential() expect to still be able to call
       * credential_write() on a struct credential whose
       * secrets have expired.
       */
      credential_clear_secrets(c);
      /* Reset expiry to maintain consistency */
      c->password_expiry_utc = TIME_MAX;
    }
    if ((c->username && c->password) || c->credential) {
      strvec_clear(&c->wwwauth_headers);
      return;
    }
    if (c->quit)
      die("credential helper '%s' told us to quit",
          c->helpers.items[i].string);
  }

  if (credential_getpass(r, c) ||
      (!c->username && !c->password && !c->credential))
    die("unable to get password from user");
}

void credential_approve(struct repository *r, struct credential *c)
{
  int i;

  if (c->approved)
    return;
  if (((!c->username || !c->password) && !c->credential) || c->password_expiry_utc < time(NULL))
    return;

  credential_next_state(c);

  credential_apply_config(r, c);

  for (i = 0; i < c->helpers.nr; i++)
    credential_do(c, c->helpers.items[i].string, "store");
  c->approved = 1;
}

void credential_reject(struct repository *r, struct credential *c)
{
  int i;

  credential_next_state(c);

  credential_apply_config(r, c);

  for (i = 0; i < c->helpers.nr; i++)
    credential_do(c, c->helpers.items[i].string, "erase");

  credential_clear_secrets(c);
  FREE_AND_NULL(c->username);
  FREE_AND_NULL(c->oauth_refresh_token);
  c->password_expiry_utc = TIME_MAX;
  c->approved = 0;
}

static int check_url_component(const char *url, int quiet,
             const char *name, const char *value)
{
  if (!value)
    return 0;
  if (!strchr(value, '\n'))
    return 0;

  if (!quiet)
    warning(_("url contains a newline in its %s component: %s"),
      name, url);
  return -1;
}

/*
 * Potentially-partial URLs can, but do not have to, contain
 *
 * - a protocol (or scheme) of the form "<protocol>://"
 *
 * - a host name (the part after the protocol and before the first slash after
 *   that, if any)
 *
 * - a user name and potentially a password (as "<user>[:<password>]@" part of
 *   the host name)
 *
 * - a path (the part after the host name, if any, starting with the slash)
 *
 * Missing parts will be left unset in `struct credential`. Thus, `https://`
 * will have only the `protocol` set, `example.com` only the host name, and
 * `/git` only the path.
 *
 * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 * be potentially partial, and only then (otherwise, the empty string is used).
 *
 * The credential_from_url() function does not allow partial URLs.
 */
static int credential_from_url_1(struct credential *c, const char *url,
         int allow_partial_url, int quiet)
{
  const char *at, *colon, *cp, *slash, *host, *proto_end;

  credential_clear(c);

  /*
   * Match one of:
   *   (1) proto://<host>/...
   *   (2) proto://<user>@<host>/...
   *   (3) proto://<user>:<pass>@<host>/...
   */
  proto_end = strstr(url, "://");
  if (!allow_partial_url && (!proto_end || proto_end == url)) {
    if (!quiet)
      warning(_("url has no scheme: %s"), url);
    return -1;
  }
  cp = proto_end ? proto_end + 3 : url;
  at = strchr(cp, '@');
  colon = strchr(cp, ':');

  /*
   * A query or fragment marker before the slash ends the host portion.
   * We'll just continue to call this "slash" for simplicity. Notably our
   * "trim leading slashes" part won't skip over this part of the path,
   * but that's what we'd want.
   */
  slash = cp + strcspn(cp, "/?#");

  if (!at || slash <= at) {
    /* Case (1) */
    host = cp;
  }
  else if (!colon || at <= colon) {
    /* Case (2) */
    c->username = url_decode_mem(cp, at - cp);
    if (c->username && *c->username)
      c->username_from_proto = 1;
    host = at + 1;
  } else {
    /* Case (3) */
    c->username = url_decode_mem(cp, colon - cp);
    if (c->username && *c->username)
      c->username_from_proto = 1;
    c->password = url_decode_mem(colon + 1, at - (colon + 1));
    host = at + 1;
  }

  if (proto_end && proto_end - url > 0)
    c->protocol = xmemdupz(url, proto_end - url);
  if (!allow_partial_url || slash - host > 0)
    c->host = url_decode_mem(host, slash - host);
  /* Trim leading and trailing slashes from path */
  while (*slash == '/')
    slash++;
  if (*slash) {
    char *p;
    c->path = url_decode(slash);
    p = c->path + strlen(c->path) - 1;
    while (p > c->path && *p == '/')
      *p-- = '\0';
  }

  if (check_url_component(url, quiet, "username", c->username) < 0 ||
      check_url_component(url, quiet, "password", c->password) < 0 ||
      check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
      check_url_component(url, quiet, "host", c->host) < 0 ||
      check_url_component(url, quiet, "path", c->path) < 0)
    return -1;

  return 0;
}

static int credential_from_potentially_partial_url(struct credential *c,
               const char *url)
{
  return credential_from_url_1(c, url, 1, 0);
}

int credential_from_url_gently(struct credential *c, const char *url, int quiet)
{
  return credential_from_url_1(c, url, 0, quiet);
}

void credential_from_url(struct credential *c, const char *url)
{
  if (credential_from_url_gently(c, url, 0) < 0)
    die(_("credential url cannot be parsed: %s"), url);
}

Coverage Report

Created: 2026-01-09 07:10