busybox/mailutils/sendmail.c

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C
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2008-11-07 05:12:42 +05:30
/* vi: set sw=4 ts=4: */
/*
* bare bones sendmail
*
* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
//config:config SENDMAIL
//config: bool "sendmail (14 kb)"
//config: default y
//config: help
//config: Barebones sendmail.
//applet:IF_SENDMAIL(APPLET(sendmail, BB_DIR_USR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_SENDMAIL) += sendmail.o mail.o
//usage:#define sendmail_trivial_usage
//usage: "[-tv] [-f SENDER] [-amLOGIN 4<user_pass.txt | -auUSER -apPASS]"
//usage: "\n [-w SECS] [-H 'PROG ARGS' | -S HOST] [RECIPIENT_EMAIL]..."
//usage:#define sendmail_full_usage "\n\n"
//usage: "Read email from stdin and send it\n"
//usage: "\nStandard options:"
//usage: "\n -t Read additional recipients from message body"
//usage: "\n -f SENDER For use in MAIL FROM:<sender>. Can be empty string"
//usage: "\n Default: -auUSER, or username of current UID"
//usage: "\n -o OPTIONS Various options. -oi implied, others are ignored"
//usage: "\n -i -oi synonym, implied and ignored"
//usage: "\n"
//usage: "\nBusybox specific options:"
//usage: "\n -v Verbose"
//usage: "\n -w SECS Network timeout"
//usage: "\n -H 'PROG ARGS' Run connection helper. Examples:"
//usage: "\n openssl s_client -quiet -tls1 -starttls smtp -connect smtp.gmail.com:25"
//usage: "\n openssl s_client -quiet -tls1 -connect smtp.gmail.com:465"
//usage: "\n $SMTP_ANTISPAM_DELAY: seconds to wait after helper connect"
//usage: "\n -S HOST[:PORT] Server (default $SMTPHOST or 127.0.0.1)"
//usage: "\n -amLOGIN Log in using AUTH LOGIN"
//usage: "\n -amPLAIN or AUTH PLAIN"
//usage: "\n (-amCRAM-MD5 not supported)"
//usage: "\n -auUSER Username for AUTH"
//usage: "\n -apPASS Password for AUTH"
//usage: "\n"
//usage: "\nIf no -a options are given, authentication is not done."
//usage: "\nIf -amLOGIN is given but no -au/-ap, user/password is read from fd #4."
//usage: "\nOther options are silently ignored; -oi is implied."
//usage: IF_MAKEMIME(
//usage: "\nUse makemime to create emails with attachments."
//usage: )
/* Currently we don't sanitize or escape user-supplied SENDER and RECIPIENT_EMAILs.
* We may need to do so. For one, '.' in usernames seems to require escaping!
*
* From http://cr.yp.to/smtp/address.html:
*
* SMTP offers three ways to encode a character inside an address:
*
* "safe": the character, if it is not <>()[].,;:@, backslash,
* double-quote, space, or an ASCII control character;
* "quoted": the character, if it is not \012, \015, backslash,
* or double-quote; or
* "slashed": backslash followed by the character.
*
* An encoded box part is either (1) a sequence of one or more slashed
* or safe characters or (2) a double quote, a sequence of zero or more
* slashed or quoted characters, and a double quote. It represents
* the concatenation of the characters encoded inside it.
*
* For example, the encoded box parts
* angels
* \a\n\g\e\l\s
* "\a\n\g\e\l\s"
* "angels"
* "ang\els"
* all represent the 6-byte string "angels", and the encoded box parts
* a\,comma
* \a\,\c\o\m\m\a
* "a,comma"
* all represent the 7-byte string "a,comma".
*
* An encoded address contains
* the byte <;
* optionally, a route followed by a colon;
* an encoded box part, the byte @, and a domain; and
* the byte >.
*
* It represents an Internet mail address, given by concatenating
* the string represented by the encoded box part, the byte @,
* and the domain. For example, the encoded addresses
* <God@heaven.af.mil>
* <\God@heaven.af.mil>
* <"God"@heaven.af.mil>
* <@gateway.af.mil,@uucp.local:"\G\o\d"@heaven.af.mil>
* all represent the Internet mail address "God@heaven.af.mil".
*/
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#include "libbb.h"
#include "mail.h"
// limit maximum allowed number of headers to prevent overflows.
// set to 0 to not limit
#define MAX_HEADERS 256
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static int smtp_checkp(const char *fmt, const char *param, int code)
{
char *answer;
char *msg = send_mail_command(fmt, param);
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// read stdin
// if the string has a form NNN- -- read next string. E.g. EHLO response
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// parse first bytes to a number
// if code = -1 then just return this number
// if code != -1 then checks whether the number equals the code
// if not equal -> die saying msg
//FIXME: limit max len!!!
while ((answer = xmalloc_fgetline(stdin)) != NULL) {
if (G.verbose)
bb_error_msg("recv:'%.*s'", (int)(strchrnul(answer, '\r') - answer), answer);
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if (strlen(answer) <= 3 || '-' != answer[3])
break;
free(answer);
}
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if (answer) {
int n = atoi(answer);
if (G.timeout)
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alarm(0);
free(answer);
if (-1 == code || n == code) {
free(msg);
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return n;
}
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}
bb_error_msg_and_die("%s failed", msg);
}
static int smtp_check(const char *fmt, int code)
{
return smtp_checkp(fmt, NULL, code);
}
// strip argument of bad chars
static char *sane_address(char *str)
{
char *s;
trim(str);
s = str;
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while (*s) {
/* Standard allows these chars in username without quoting:
* /!#$%&'*+-=?^_`{|}~
* and allows dot (.) with some restrictions.
* I chose to only allow a saner subset.
* I propose to expand it only on user's request.
*/
if (!isalnum(*s) && !strchr("=+_-.@", *s)) {
bb_error_msg("bad address '%s'", str);
/* returning "": */
str[0] = '\0';
return str;
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}
s++;
}
return str;
}
// check for an address inside angle brackets, if not found fall back to normal
static char *angle_address(char *str)
{
char *s, *e;
e = trim(str);
if (e != str && *--e == '>') {
s = strrchr(str, '<');
if (s) {
*e = '\0';
str = s + 1;
}
}
return sane_address(str);
}
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static void rcptto(const char *s)
{
if (!*s)
return;
// N.B. we don't die if recipient is rejected, for the other recipients may be accepted
if (250 != smtp_checkp("RCPT TO:<%s>", s, -1))
bb_error_msg("Bad recipient: <%s>", s);
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}
// send to a list of comma separated addresses
static void rcptto_list(const char *list)
{
char *free_me = xstrdup(list);
char *str = free_me;
char *s = free_me;
char prev = 0;
int in_quote = 0;
while (*s) {
char ch = *s++;
if (ch == '"' && prev != '\\') {
in_quote = !in_quote;
} else if (!in_quote && ch == ',') {
s[-1] = '\0';
rcptto(angle_address(str));
str = s;
}
prev = ch;
}
if (prev != ',')
rcptto(angle_address(str));
free(free_me);
}
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int sendmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int sendmail_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opts;
char *opt_connect;
char *opt_from = NULL;
char *s;
llist_t *list = NULL;
char *host = sane_address(safe_gethostname());
unsigned nheaders = 0;
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int code;
enum {
HDR_OTHER = 0,
HDR_TOCC,
HDR_BCC,
} last_hdr = 0;
int check_hdr;
int has_to = 0;
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enum {
//--- standard options
OPT_t = 1 << 0, // read message for recipients, append them to those on cmdline
OPT_f = 1 << 1, // sender address
OPT_o = 1 << 2, // various options. -oi IMPLIED! others are IGNORED!
OPT_i = 1 << 3, // IMPLIED!
//--- BB specific options
OPT_w = 1 << 4, // network timeout
OPT_H = 1 << 5, // use external connection helper
OPT_S = 1 << 6, // specify connection string
OPT_a = 1 << 7, // authentication tokens
OPT_v = 1 << 8, // verbosity
//--- for -amMETHOD
OPT_am_plain = 1 << 9, // AUTH PLAIN
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};
// init global variables
INIT_G();
// default HOST[:PORT] is $SMTPHOST, or localhost
opt_connect = getenv("SMTPHOST");
if (!opt_connect)
opt_connect = (char *)"127.0.0.1";
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// save initial stdin since body is piped!
xdup2(STDIN_FILENO, 3);
G.fp0 = xfdopen_for_read(3);
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// parse options
// N.B. since -H and -S are mutually exclusive they do not interfere in opt_connect
// -a is for ssmtp (http://downloads.openwrt.org/people/nico/man/man8/ssmtp.8.html) compatibility,
// it is still under development.
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
opts = getopt32(argv, "^"
"tf:o:iw:+H:S:a:*:v"
"\0"
// -v is a counter, -H and -S are mutually exclusive, -a is a list
"vv:H--S:S--H",
&opt_from, NULL,
&G.timeout, &opt_connect, &opt_connect, &list, &G.verbose
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
);
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//argc -= optind;
argv += optind;
// process -a[upm]<token> options
if ((opts & OPT_a) && !list)
bb_show_usage();
while (list) {
char *a = (char *) llist_pop(&list);
if ('u' == a[0])
G.user = xstrdup(a+1);
if ('p' == a[0])
G.pass = xstrdup(a+1);
if ('m' == a[0]) {
if ((a[1] | 0x20) == 'p') // PLAIN
opts |= OPT_am_plain;
else if ((a[1] | 0x20) == 'l') // LOGIN
; /* do nothing (this is the default) */
else
bb_error_msg_and_die("unsupported AUTH method %s", a+1);
}
}
// N.B. list == NULL here
//bb_error_msg("OPT[%x] AU[%s], AP[%s], AM[%s], ARGV[%s]", opts, au, ap, am, *argv);
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// connect to server
// connection helper ordered? ->
if (opts & OPT_H) {
const char *delay;
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const char *args[] = { "sh", "-c", opt_connect, NULL };
// plug it in
launch_helper(args);
// 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.
//
// If $SMTP_ANTISPAM_DELAY is set, we pause before sending NOOP.
//
delay = getenv("SMTP_ANTISPAM_DELAY");
if (delay)
sleep(atoi(delay));
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)
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die("SMTP init failed");
} else {
// vanilla connection
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int fd;
fd = create_and_connect_stream_or_die(opt_connect, 25);
// and make ourselves a simple IO filter
xmove_fd(fd, STDIN_FILENO);
xdup2(STDIN_FILENO, STDOUT_FILENO);
// Wait for initial server 220 message
smtp_check(NULL, 220);
}
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// we should start with modern EHLO
if (250 != smtp_checkp("EHLO %s", host, -1))
smtp_checkp("HELO %s", host, 250);
// perform authentication
if (opts & OPT_a) {
// read credentials unless they are given via -a[up] options
if (!G.user || !G.pass)
get_cred_or_die(4);
if (opts & OPT_am_plain) {
// C: AUTH PLAIN
// S: 334
// C: base64encoded(auth<NUL>user<NUL>pass)
// S: 235 2.7.0 Authentication successful
//Note: a shorter format is allowed:
// C: AUTH PLAIN base64encoded(auth<NUL>user<NUL>pass)
// S: 235 2.7.0 Authentication successful
smtp_check("AUTH PLAIN", 334);
{
unsigned user_len = strlen(G.user);
unsigned pass_len = strlen(G.pass);
unsigned sz = 1 + user_len + 1 + pass_len;
char plain_auth[sz + 1];
// the format is:
// "authorization identity<NUL>username<NUL>password"
// authorization identity is empty.
plain_auth[0] = '\0';
strcpy(stpcpy(plain_auth + 1, G.user) + 1, G.pass);
printbuf_base64(plain_auth, sz);
}
} else {
// C: AUTH LOGIN
// S: 334 VXNlcm5hbWU6
// ^^^^^^^^^^^^ server says "Username:"
// C: base64encoded(user)
// S: 334 UGFzc3dvcmQ6
// ^^^^^^^^^^^^ server says "Password:"
// C: base64encoded(pass)
// S: 235 2.7.0 Authentication successful
smtp_check("AUTH LOGIN", 334);
printstr_base64(G.user);
smtp_check("", 334);
printstr_base64(G.pass);
}
smtp_check("", 235);
}
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// set sender
// N.B. we have here a very loosely defined algorythm
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// 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.
// 2) server can require AUTH ->
// we must provide valid username and password along with a (possibly fake) reply address.
// For the sake of security username and password are to be read either from console or from a secured file.
// Since reading from console may defeat usability, the solution is either to read from a predefined
// file descriptor (e.g. 4), or again from a secured file.
// got no sender address? use auth name, then UID username as a last resort
if (!opt_from) {
opt_from = xasprintf("%s@%s",
G.user ? G.user : xuid2uname(getuid()),
xgethostbyname(host)->h_name);
}
free(host);
smtp_checkp("MAIL FROM:<%s>", opt_from, 250);
// process message
// read recipients from message and add them to those given on cmdline.
// this means we scan stdin for To:, Cc:, Bcc: lines until an empty line
// and then use the rest of stdin as message body
code = 0; // set "analyze headers" mode
//FIXME: limit max len!!!
while ((s = xmalloc_fgetline(G.fp0)) != NULL) {
dump:
// put message lines doubling leading dots
if (code) {
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// escape leading dots
// N.B. this feature is implied even if no -i (-oi) switch given
// N.B. we need to escape the leading dot regardless of
// whether it is single or not character on the line
if ('.' == s[0] /*&& '\0' == s[1] */)
bb_putchar('.');
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// dump read line
send_r_n(s);
free(s);
continue;
}
// analyze headers
// To: or Cc: headers add recipients
check_hdr = (0 == strncasecmp("To:", s, 3));
has_to |= check_hdr;
if (opts & OPT_t) {
if (check_hdr || 0 == strncasecmp("Bcc:" + 1, s, 3)) {
rcptto_list(s+3);
last_hdr = HDR_TOCC;
goto addheader;
}
// Bcc: header adds blind copy (hidden) recipient
if (0 == strncasecmp("Bcc:", s, 4)) {
rcptto_list(s+4);
free(s);
last_hdr = HDR_BCC;
continue; // N.B. Bcc: vanishes from headers!
}
}
check_hdr = (list && isspace(s[0]));
if (strchr(s, ':') || check_hdr) {
// 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.
if (check_hdr && last_hdr != HDR_OTHER) {
rcptto_list(s+1);
if (last_hdr == HDR_BCC)
continue;
// N.B. Bcc: vanishes from headers!
} else {
last_hdr = HDR_OTHER;
}
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);
} 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
check_hdr = 1;
while (*argv) {
char *t = sane_address(*argv);
rcptto(t);
//if (MAX_HEADERS && ++nheaders >= MAX_HEADERS)
// goto bail;
if (!has_to) {
const char *hdr;
if (check_hdr && argv[1])
hdr = "To: %s,";
else if (check_hdr)
hdr = "To: %s";
else if (argv[1])
hdr = "To: %s," + 3;
else
hdr = "To: %s" + 3;
llist_add_to_end(&list,
xasprintf(hdr, t));
check_hdr = 0;
}
argv++;
}
// enter "put message" mode
// N.B. DATA fails iff no recipients were accepted (or even provided)
// in this case just bail out gracefully
if (354 != smtp_check("DATA", -1))
goto bail;
// dump the headers
while (list) {
send_r_n((char *) llist_pop(&list));
}
// stop analyzing headers
code++;
// N.B. !s means: we read nothing, and nothing to be read in the future.
// just dump empty line and break the loop
if (!s) {
send_r_n("");
break;
}
// go dump message body
// N.B. "s" already contains the first non-header line, so pretend we read it from input
goto dump;
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}
}
// odd case: we didn't stop "analyze headers" mode -> message body is empty. Reenter the loop
// N.B. after reenter code will be > 0
if (!code)
goto reenter;
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// finalize the message
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smtp_check(".", 250);
bail:
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// ... and say goodbye
smtp_check("QUIT", 221);
// cleanup
if (ENABLE_FEATURE_CLEAN_UP)
fclose(G.fp0);
return EXIT_SUCCESS;
}