diff options
Diffstat (limited to 'transact.c')
| -rw-r--r-- | transact.c | 91 |
1 files changed, 53 insertions, 38 deletions
@@ -377,6 +377,11 @@ int readheaders(int sock, if (msgblk.headers) free(msgblk.headers); + /* initially, no message ID */ + if (ctl->thisid) + free(ctl->thisid); + ctl->thisid = NULL; + msgblk.headers = received_for = delivered_to = NULL; from_offs = reply_to_offs = resent_from_offs = app_from_offs = sender_offs = resent_sender_offs = env_offs = -1; @@ -514,44 +519,9 @@ int readheaders(int sock, /* we see an ordinary (non-header, non-message-delimiter line */ has_nuls = (linelen != strlen(line)); - /* - * When mail delivered to a multidrop mailbox on the server is - * addressed to multiple people on the client machine, there - * will be one copy left in the box for each recipient. Thus, - * if the mail is addressed to N people, each recipient will - * get N copies. This is bad when N > 1. - * - * Foil this by suppressing all but one copy of a message with - * a given Message-ID. The accept_count test ensures that - * multiple pieces of email with the same Message-ID, each - * with a *single* addressee (the N == 1 case), won't be - * suppressed. - * - * Note: This implementation only catches runs of successive - * messages with the same ID, but that should be good - * enough. A more general implementation would have to store - * ever-growing lists of seen message-IDs; in a long-running - * daemon this would turn into a memory leak even if the - * implementation were perfect. - * - * Don't mess with this code casually. It would be way too easy - * to break it in a way that blackholed mail. Better to pass - * the occasional duplicate than to do that... - */ + /* save the message's ID, we may use it for killing duplicates later */ if (MULTIDROP(ctl) && !strncasecmp(line, "Message-ID:", 11)) - { - if (ctl->lastid && !strcasecmp(ctl->lastid, line)) - { - if (accept_count > 1) - return(PS_REFUSED); - } - else - { - if (ctl->lastid) - free(ctl->lastid); - ctl->lastid = xstrdup(line); - } - } + ctl->thisid = xstrdup(line); /* * The University of Washington IMAP server (the reference @@ -811,7 +781,52 @@ int readheaders(int sock, } } - process_headers: + process_headers: + /* + * When mail delivered to a multidrop mailbox on the server is + * addressed to multiple people on the client machine, there will + * be one copy left in the box for each recipient. This is not a + * problem if we have the actual recipient address to dispatch on + * (e.g. because we've mined it out of sendmail trace headers, or + * a qmail Delivered-To line, or a declared sender envelope line). + * + * But if we're mining addressees out of the To/Cc/Bcc fields, and + * if the mail is addressed to N people, each recipient will + * get N copies. This is bad when N > 1. + * + * Foil this by suppressing all but one copy of a message with + * a given Message-ID. The accept_count test ensures that + * multiple pieces of email with the same Message-ID, each + * with a *single* addressee (the N == 1 case), won't be + * suppressed. + * + * Note: This implementation only catches runs of successive + * messages with the same ID, but that should be good + * enough. A more general implementation would have to store + * ever-growing lists of seen message-IDs; in a long-running + * daemon this would turn into a memory leak even if the + * implementation were perfect. + * + * Don't mess with this code casually. It would be way too easy + * to break it in a way that blackholed mail. Better to pass + * the occasional duplicate than to do that... + */ + if (!received_for && env_offs == -1 && !delivered_to) + { + if (ctl->lastid && ctl->thisid && !strcasecmp(ctl->lastid, ctl->thisid)) + { + if (accept_count > 1) + return(PS_REFUSED); + } + else + { + if (ctl->lastid) + free(ctl->lastid); + ctl->lastid = ctl->thisid; + ctl->thisid = NULL; + } + } + /* * We want to detect this early in case there are so few headers that the * dispatch logic barfs. |