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34c469ae0

Denys Vlasenko
Denys Vlasenko
2011-09-18
FAILED Duration: 207s

Subject

sendmail: don't talk until 220 code is seen. Closes 3487

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

mailutils/mail.c +7 -4mailutils/sendmail.c +51 -39
mailutils/mail.c+7 -4
@@ -57,10 +57,13 @@ void FAST_FUNC launch_helper(const char **argv)
G.helper_pid = xvfork();
i = (!G.helper_pid) * 2; // for parent:0, for child:2
- close(pipes[i + 1]); // 1 or 3 - closing one write end
- close(pipes[2 - i]); // 2 or 0 - closing one read end
- xmove_fd(pipes[i], STDIN_FILENO); // 0 or 2 - using other read end
- xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - other write end
+ close(pipes[i + 1]); // 1 or 3 - closing one write end
+ close(pipes[2 - i]); // 2 or 0 - closing one read end
+ xmove_fd(pipes[i], STDIN_FILENO); // 0 or 2 - using other read end
+ xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - using other write end
+ // End result:
+ // parent stdout [3] -> child stdin [2]
+ // child stdout [1] -> parent stdin [0]
if (!G.helper_pid) {
// child: try to execute connection helper
mailutils/sendmail.c+51 -39
@@ -26,18 +26,18 @@
//usage: "\n Examples:"
//usage: "\n -H 'exec openssl s_client -quiet -tls1 -starttls smtp"
//usage: "\n -connect smtp.gmail.com:25' <email.txt"
-//usage: "\n [4<username_and_passwd.txt | -au<username> -ap<password>]"
+//usage: "\n [4<username_and_passwd.txt | -auUSER -apPASS]"
//usage: "\n -H 'exec openssl s_client -quiet -tls1"
//usage: "\n -connect smtp.gmail.com:465' <email.txt"
-//usage: "\n [4<username_and_passwd.txt | -au<username> -ap<password>]"
+//usage: "\n [4<username_and_passwd.txt | -auUSER -apPASS]"
//usage: "\n -S HOST[:PORT] Server"
-//usage: "\n -au<username> Username for AUTH LOGIN"
-//usage: "\n -ap<password> Password for AUTH LOGIN"
-//usage: "\n -am<method> Authentication method. Ignored. LOGIN is implied"
+//usage: "\n -auUSER Username for AUTH LOGIN"
+//usage: "\n -apPASS Password for AUTH LOGIN"
+////usage: "\n -amMETHOD Authentication method. Ignored. LOGIN is implied"
//usage: "\n"
//usage: "\nOther options are silently ignored; -oi -t is implied"
//usage: IF_MAKEMIME(
-//usage: "\nUse makemime applet to create message with attachments"
+//usage: "\nUse makemime to create emails with attachments"
//usage: )
#include "libbb.h"
@@ -66,7 +66,7 @@ static int smtp_checkp(const char *fmt, const char *param, int code)
// if not equal -> die saying msg
while ((answer = xmalloc_fgetline(stdin)) != NULL) {
if (verbose)
- bb_error_msg("recv:'%.*s' %d", (int)(strchrnul(answer, '\r') - answer), answer, verbose);
+ bb_error_msg("recv:'%.*s'", (int)(strchrnul(answer, '\r') - answer), answer);
if (strlen(answer) <= 3 || '-' != answer[3])
break;
free(answer);
@@ -75,10 +75,11 @@ static int smtp_checkp(const char *fmt, const char *param, int code)
int n = atoi(answer);
if (timeout)
alarm(0);
- free(msg);
free(answer);
- if (-1 == code || n == code)
+ if (-1 == code || n == code) {
+ free(msg);
return n;
+ }
}
bb_error_msg_and_die("%s failed", msg);
}
@@ -176,11 +177,35 @@ int sendmail_main(int argc UNUSED_PARAM, char **argv)
const char *args[] = { "sh", "-c", opt_connect, NULL };
// plug it in
launch_helper(args);
- // vanilla connection
+ // Now:
+ // our stdout will go to helper's stdin,
+ // helper's stdout will be available on our stdin.
+
+ // Wait for initial server message.
+ // If helper (such as openssl) invokes STARTTLS, the initial 220
+ // is swallowed by helper (and not repeated after TLS is initiated).
+ // We will send NOOP cmd to server and check the response.
+ // We should get 220+250 on plain connection, 250 on STARTTLSed session.
+ //
+ // The problem here is some servers delay initial 220 message,
+ // and consider client to be a spammer if it starts sending cmds
+ // before 220 reached it. The code below is unsafe in this regard:
+ // in non-STARTTLSed case, we potentially send NOOP before 220
+ // is sent by server.
+ // Ideas? (--delay SECS opt? --assume-starttls-helper opt?)
+ code = smtp_check("NOOP", -1);
+ if (code == 220)
+ // we got 220 - this is not STARTTLSed connection,
+ // eat 250 response to our NOOP
+ smtp_check(NULL, 250);
+ else
+ if (code != 250)
+ bb_error_msg_and_die("SMTP init failed");
} else {
+ // vanilla connection
int fd;
// host[:port] not explicitly specified? -> use $SMTPHOST
- // no $SMTPHOST ? -> use localhost
+ // no $SMTPHOST? -> use localhost
if (!(opts & OPT_S)) {
opt_connect = getenv("SMTPHOST");
if (!opt_connect)
@@ -191,25 +216,14 @@ int sendmail_main(int argc UNUSED_PARAM, char **argv)
// and make ourselves a simple IO filter
xmove_fd(fd, STDIN_FILENO);
xdup2(STDIN_FILENO, STDOUT_FILENO);
- }
- // N.B. from now we know nothing about network :)
- // wait for initial server OK
- // N.B. if we used openssl the initial 220 answer is already swallowed during openssl TLS init procedure
- // so we need to kick the server to see whether we are ok
- code = smtp_check("NOOP", -1);
- // 220 on plain connection, 250 on openssl-helped TLS session
- if (220 == code)
- smtp_check(NULL, 250); // reread the code to stay in sync
- else if (250 != code)
- bb_error_msg_and_die("INIT failed");
+ // Wait for initial server 220 message
+ smtp_check(NULL, 220);
+ }
// we should start with modern EHLO
- if (250 != smtp_checkp("EHLO %s", domain, -1)) {
+ if (250 != smtp_checkp("EHLO %s", domain, -1))
smtp_checkp("HELO %s", domain, 250);
- }
- if (ENABLE_FEATURE_CLEAN_UP)
- free(domain);
// perform authentication
if (opts & OPT_a) {
@@ -224,7 +238,7 @@ int sendmail_main(int argc UNUSED_PARAM, char **argv)
}
// set sender
- // N.B. we have here a very loosely defined algotythm
+ // N.B. we have here a very loosely defined algorythm
// since sendmail historically offers no means to specify secrets on cmdline.
// 1) server can require no authentication ->
// we must just provide a (possibly fake) reply address.
@@ -241,8 +255,6 @@ int sendmail_main(int argc UNUSED_PARAM, char **argv)
// G.user = xuid2uname(getuid());
// opt_from = xasprintf("%s@%s", G.user, domain);
//}
- //if (ENABLE_FEATURE_CLEAN_UP)
- // free(domain);
smtp_checkp("MAIL FROM:<%s>", opt_from, 250);
// process message
@@ -272,26 +284,26 @@ int sendmail_main(int argc UNUSED_PARAM, char **argv)
if (0 == strncasecmp("To:", s, 3) || 0 == strncasecmp("Bcc:" + 1, s, 3)) {
rcptto(sane_address(s+3));
goto addheader;
+ }
// Bcc: header adds blind copy (hidden) recipient
- } else if (0 == strncasecmp("Bcc:", s, 4)) {
+ if (0 == strncasecmp("Bcc:", s, 4)) {
rcptto(sane_address(s+4));
free(s);
// N.B. Bcc: vanishes from headers!
-
- // other headers go verbatim
-
- // N.B. RFC2822 2.2.3 "Long Header Fields" allows for headers to occupy several lines.
- // Continuation is denoted by prefixing additional lines with whitespace(s).
- // Thanks (stefan.seyfried at googlemail.com) for pointing this out.
- } else if (strchr(s, ':') || (list && skip_whitespace(s) != s)) {
+ } else
+ if (strchr(s, ':') || (list && skip_whitespace(s) != s)) {
+ // other headers go verbatim
+ // N.B. RFC2822 2.2.3 "Long Header Fields" allows for headers to occupy several lines.
+ // Continuation is denoted by prefixing additional lines with whitespace(s).
+ // Thanks (stefan.seyfried at googlemail.com) for pointing this out.
addheader:
// N.B. we allow MAX_HEADERS generic headers at most to prevent attacks
if (MAX_HEADERS && ++nheaders >= MAX_HEADERS)
goto bail;
llist_add_to_end(&list, s);
- // a line without ":" (an empty line too, by definition) doesn't look like a valid header
- // so stop "analyze headers" mode
} else {
+ // a line without ":" (an empty line too, by definition) doesn't look like a valid header
+ // so stop "analyze headers" mode
reenter:
// put recipients specified on cmdline
while (*argv) {