seg fault when sending more than one email #30
Description
If I try to send an email more than once in the same process, it crashes in smtp_start_session(). The last event I see from the attempt is SMTP_EV_CONNECT before it fails. The first attempt works great. Any attempts after that fail.
(I was able to reproduce this in the example mail-file.c as well.)
First, here is my function that I'm calling to send an email:
int send_email(char *subject) {
smtp_session_t session = smtp_create_session();
smtp_message_t message = smtp_add_message(session);
smtp_recipient_t recipient;
const smtp_status_t *status;
enum notify_flags notify = Notify_NOTSET;
int res = smtp_starttls_enable(session, Starttls_REQUIRED);
auth_context_t authctx = auth_create_context ();
auth_set_mechanism_flags (authctx, AUTH_PLUGIN_PLAIN, 0);
auth_set_interact_cb (authctx, authinteract, NULL);
smtp_set_eventcb(session, event_cb, NULL);
smtp_auth_set_context (session, authctx);
smtp_set_header(message, "From", "House Controller", "<REDACTED>");
smtp_set_header(message, "To", NULL, "<REDACTED>");
smtp_set_header(message, "Subject", subject);
smtp_set_server(session, "smtp.gmail.com:587");
FILE* fd = fopen("test-mail", "r"); // this is the same test-mail file the came with the example code. The behavior persists with my own files too
smtp_set_message_fp(message, fd);
recipient = smtp_add_recipient(message, "<REDACTED>");
notify = Notify_SUCCESS | Notify_FAILURE | Notify_DELAY;
smtp_dsn_set_notify (recipient, notify);
if (!smtp_start_session(session)) {
printf("failed to start session\n");
smtp_destroy_session(session);
auth_destroy_context (authctx);
fclose(fd);
auth_client_exit();
return 1;
}
smtp_destroy_session(session);
auth_destroy_context (authctx);
fclose(fd);
auth_client_exit();
return 0;
}I can call the above function ONCE in my program, per process instance. Another call will crash. I can call it once, close the program, then call it again no problem. Just never more than once per process instance.
I also reproduced the issue with the example code. The following modifications to the mail-file.c example reproduces the crash:
...
...
/* Free resources consumed by the program.
*/
smtp_destroy_session (session);
auth_destroy_context (authctx);
fclose (fp);
auth_client_exit ();
// <my additions>
// now do it again
printf("waiting 10 seconds...\n");
sleep(10);
auth_client_init ();
session = smtp_create_session ();
message = smtp_add_message (session);
smtp_starttls_enable (session, Starttls_REQUIRED);
smtp_set_server (session, host ? host : "localhost:25");
authctx = auth_create_context ();
auth_set_mechanism_flags (authctx, AUTH_PLUGIN_PLAIN, 0);
auth_set_interact_cb (authctx, authinteract, NULL);
smtp_set_eventcb(session, event_cb, NULL);
smtp_set_reverse_path (message, from);
smtp_set_header (message, "To", NULL, NULL);
fp = fopen (file, "r");
smtp_set_message_fp (message, fp);
recipient = smtp_add_recipient (message, "<REDACTED>");
smtp_dsn_set_notify (recipient, notify);
if (!smtp_start_session (session))
{
char buf[128];
fprintf (stderr, "SMTP server problem %s\n",
smtp_strerror (smtp_errno (), buf, sizeof buf));
}
else
{
/* Report on the success or otherwise of the mail transfer.
*/
status = smtp_message_transfer_status (message);
printf ("%d %s", status->code,
(status->text != NULL) ? status->text : "\n");
smtp_enumerate_recipients (message, print_recipient_status, NULL);
}
/* Free resources consumed by the program.
*/
smtp_destroy_session (session);
auth_destroy_context (authctx);
fclose (fp);
auth_client_exit ();
// </my additions>
exit (0);
}The above experiment also crashes in the second call to smtp_start_session().
Can reproduce in ubuntu 22.04 and Arch.
Before I start diving too much deeper, has anyone seen this before? Perhaps I'm not tearing down the session correctly?
Thanks for reading all that.