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ask-password-api: several modernizations for ask_password_agent()

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* Replace goto cleanup with block_signals_reset + CLEANUP_TMPFILE_AT
* Use RENAME_NOREPLACE to make sure we don't overwrite any ongoing request
* Reword log messages a bit
This commit is contained in:
Mike Yuan
2026-02-11 02:39:26 +01:00
parent 41615d59fa
commit 4153a2a6f4
1 changed files with 87 additions and 134 deletions
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src/shared/ask-password-api.c
+87 -134
View File
@@ -831,10 +831,6 @@ int ask_password_agent(
_cleanup_close_ int socket_fd = -EBADF, signal_fd = -EBADF, inotify_fd = -EBADF, dfd = -EBADF;
_cleanup_(unlink_and_freep) char *socket_name = NULL;
_cleanup_free_ char *temp = NULL, *final = NULL;
_cleanup_strv_free_erase_ char **l = NULL;
_cleanup_fclose_ FILE *f = NULL;
sigset_t mask, oldmask;
int r;
assert(req);
@@ -850,64 +846,59 @@ int ask_password_agent(
if (req->flag_file)
return -EOPNOTSUPP;
_cleanup_free_ char *askpwdir = NULL;
r = get_ask_password_directory_for_flags(flags, &askpwdir);
if (r < 0)
return r;
if (r == 0)
return -ENXIO;
dfd = open_mkdir(askpwdir, O_CLOEXEC, 0755);
if (dfd < 0)
return log_debug_errno(dfd, "Failed to open directory '%s': %m", askpwdir);
if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && req->keyring) {
r = ask_password_keyring(req, flags, ret);
if (r != -ENOKEY)
return r;
inotify_fd = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
if (inotify_fd < 0)
return -errno;
r = inotify_add_watch_fd(inotify_fd, dfd, IN_ONLYDIR|IN_ATTRIB /* for mtime */);
if (r < 0)
return r;
}
sigset_t mask, oldmask;
_unused_ _cleanup_(block_signals_reset) sigset_t *saved_ssp = NULL;
assert_se(sigemptyset(&mask) >= 0);
assert_se(sigset_add_many(&mask, SIGINT, SIGTERM) >= 0);
assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
_cleanup_free_ char *askpwdir = NULL;
r = get_ask_password_directory_for_flags(flags, &askpwdir);
saved_ssp = &oldmask;
_cleanup_free_ char *fname = NULL, *final = NULL;
_cleanup_fclose_ FILE *f = NULL;
if (asprintf(&final, "ask.%" PRIu64, random_u64()) < 0)
return -ENOMEM;
r = fopen_temporary_at(dfd, final, &f, &fname);
if (r < 0)
goto finish;
if (r == 0) {
r = -ENXIO;
goto finish;
}
return r;
dfd = open_mkdir(askpwdir, O_RDONLY|O_CLOEXEC, 0755);
if (dfd < 0) {
r = log_debug_errno(dfd, "Failed to open directory '%s': %m", askpwdir);
goto finish;
}
if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && req->keyring) {
r = ask_password_keyring(req, flags, ret);
if (r >= 0) {
r = 0;
goto finish;
} else if (r != -ENOKEY)
goto finish;
inotify_fd = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
if (inotify_fd < 0) {
r = -errno;
goto finish;
}
r = inotify_add_watch_fd(inotify_fd, dfd, IN_ONLYDIR|IN_ATTRIB /* for mtime */);
if (r < 0)
goto finish;
}
if (asprintf(&final, "ask.%" PRIu64, random_u64()) < 0) {
r = -ENOMEM;
goto finish;
}
r = fopen_temporary_at(dfd, final, &f, &temp);
if (r < 0)
goto finish;
CLEANUP_TMPFILE_AT(dfd, fname);
signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
if (signal_fd < 0) {
r = -errno;
goto finish;
}
if (signal_fd < 0)
return -errno;
socket_fd = create_socket(askpwdir, &socket_name);
if (socket_fd < 0) {
r = socket_fd;
goto finish;
}
if (socket_fd < 0)
return socket_fd;
fprintf(f,
"[Ask]\n"
@@ -933,21 +924,19 @@ int ask_password_agent(
if (req->id)
fprintf(f, "Id=%s\n", req->id);
if (fchmod(fileno(f), 0644) < 0) {
r = -errno;
goto finish;
}
if (fchmod(fileno(f), 0644) < 0)
return -errno;
r = fflush_and_check(f);
if (r < 0)
goto finish;
return r;
if (renameat(dfd, temp, dfd, final) < 0) {
r = -errno;
goto finish;
}
/* Paranoia: never clobber an ongoing request */
r = rename_noreplace(dfd, fname, dfd, final);
if (r < 0)
return r;
temp = mfree(temp);
free_and_replace(fname, final);
enum {
POLL_SOCKET,
@@ -969,20 +958,17 @@ int ask_password_agent(
.events = POLLIN,
};
if (req->hup_fd >= 0)
pollfd[hup_fd_idx = n_pollfd ++] = (struct pollfd) {
pollfd[hup_fd_idx = n_pollfd++] = (struct pollfd) {
.fd = req->hup_fd,
.events = POLLHUP,
};
assert(n_pollfd <= _POLL_MAX);
_cleanup_strv_free_erase_ char **l = NULL;
for (;;) {
CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
char passphrase[LINE_MAX+1];
struct iovec iovec;
struct ucred *ucred;
usec_t timeout;
ssize_t n;
if (req->until > 0)
timeout = usec_sub_unsigned(req->until, now(CLOCK_MONOTONIC));
@@ -993,45 +979,34 @@ int ask_password_agent(
if (r == -EINTR)
continue;
if (r < 0)
goto finish;
if (r == 0) {
r = -ETIME;
goto finish;
}
return r;
if (r == 0)
return -ETIME;
if (pollfd[POLL_SIGNAL].revents & POLLIN) {
r = -EINTR;
goto finish;
}
if (pollfd[POLL_SIGNAL].revents & POLLIN)
return -EINTR;
if (req->hup_fd >= 0 && pollfd[hup_fd_idx].revents & POLLHUP) {
r = -ECONNRESET;
goto finish;
}
if (req->hup_fd >= 0 && pollfd[hup_fd_idx].revents & POLLHUP)
return -ECONNRESET;
if (inotify_fd >= 0 && pollfd[inotify_idx].revents != 0) {
(void) flush_fd(inotify_fd);
if (req->keyring) {
r = ask_password_keyring(req, flags, ret);
if (r >= 0) {
r = 0;
goto finish;
} else if (r != -ENOKEY)
goto finish;
if (r != -ENOKEY)
return r;
}
}
if (pollfd[POLL_SOCKET].revents == 0)
continue;
if (pollfd[POLL_SOCKET].revents != POLLIN)
return -EIO;
if (pollfd[POLL_SOCKET].revents != POLLIN) {
r = -EIO;
goto finish;
}
iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
char passphrase[LINE_MAX+1];
struct iovec iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
struct msghdr msghdr = {
.msg_iov = &iovec,
.msg_iovlen = 1,
@@ -1039,7 +1014,7 @@ int ask_password_agent(
.msg_controllen = sizeof(control),
};
n = recvmsg_safe(socket_fd, &msghdr, 0);
ssize_t n = recvmsg_safe(socket_fd, &msghdr, 0);
if (ERRNO_IS_NEG_TRANSIENT(n))
continue;
if (n == -ECHRNG) {
@@ -1050,30 +1025,30 @@ int ask_password_agent(
log_debug_errno(n, "Got message with truncated payload data, ignoring.");
continue;
}
if (n < 0) {
r = (int) n;
goto finish;
}
if (n < 0)
return n;
CLEANUP_ERASE(passphrase);
cmsg_close_all(&msghdr);
if (n == 0) {
log_debug("Message too short");
log_debug("Got empty reply from ask-password agent, ignoring.");
continue;
}
ucred = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
struct ucred *ucred = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
if (!ucred) {
log_debug("Received message without credentials. Ignoring.");
log_debug("Received message without credentials, ignoring.");
continue;
}
if (ucred->uid != getuid() && ucred->uid != 0) {
log_debug("Got password response from bad user, ignoring.");
continue;
}
if (ucred->uid != getuid() && ucred->uid != 0) {
log_debug("Got response from bad user. Ignoring.");
continue;
}
if (passphrase[0] == '-')
return -ECANCELED;
if (passphrase[0] == '+') {
/* An empty message refers to the empty password */
@@ -1081,45 +1056,23 @@ int ask_password_agent(
l = strv_new("");
else
l = strv_parse_nulstr(passphrase+1, n-1);
if (!l) {
r = -ENOMEM;
goto finish;
}
if (!l)
return -ENOMEM;
if (strv_isempty(l)) {
l = strv_free(l);
log_debug("Invalid packet");
continue;
}
if (!strv_isempty(l))
break;
break;
l = strv_free(l);
}
if (passphrase[0] == '-') {
r = -ECANCELED;
goto finish;
}
log_debug("Invalid packet");
log_debug("Got invalid response from ask-password agent, ignoring.");
}
if (req->keyring)
(void) add_to_keyring_and_log(req->keyring, flags, l);
*ret = TAKE_PTR(l);
r = 0;
finish:
if (temp) {
assert(dfd >= 0);
(void) unlinkat(dfd, temp, 0);
} else if (final) {
assert(dfd >= 0);
(void) unlinkat(dfd, final, 0);
}
assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
return r;
return 0;
}
static int ask_password_credential(const AskPasswordRequest *req, AskPasswordFlags flags, char ***ret) {