36d7678ec9
From https://www.fehcom.de/qmail/smtpauth.html#PATCHES Generic SMTP authentication for qmail-smtpd and qmail-remote. Complies to RFC 3848 and RFC 4409. * Provides now CRAM-MD5 authentication for qmail-remote as well. * Fine tuning of SMTPAUTH annoncements for qmail-smtpd and SUBMISSION support. * Sender based authentication according to 'Mail From:' and authenticated smarthost relaying for qmail-remote. * Fixed bug (0.8.2): qmail-smtpd secretly allows auth even when disabled! (tx Chris P.) * Fixed AMD64 bug for MD5 (0.8.3) and small others (tx Alan P.)
76 lines
2.6 KiB
C
76 lines
2.6 KiB
C
#include "global.h"
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#include "md5.h"
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/*
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** Function: hmac_md5
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*/
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void hmac_md5(text, text_len, key, key_len, digest)
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unsigned char* text; /* pointer to data stream */
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int text_len; /* length of data stream */
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unsigned char* key; /* pointer to authentication key */
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int key_len; /* length of authentication key */
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unsigned char *digest; /* caller digest to be filled in */
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{
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MD5_CTX context;
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unsigned char k_ipad[65]; /* inner padding -
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* key XORd with ipad
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*/
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unsigned char k_opad[65]; /* outer padding -
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* key XORd with opad
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*/
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unsigned char tk[16];
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int i;
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/* if key is longer than 64 bytes reset it to key=MD5(key) */
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if (key_len > 64) {
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MD5_CTX tctx;
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MD5Init(&tctx);
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MD5Update(&tctx, key, key_len);
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MD5Final(tk, &tctx);
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key = tk;
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key_len = 16;
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}
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/*
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* the HMAC_MD5 transform looks like:
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*
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* MD5(K XOR opad, MD5(K XOR ipad, text))
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*
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* where K is an n byte key
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* ipad is the byte 0x36 repeated 64 times
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* opad is the byte 0x5c repeated 64 times
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* and text is the data being protected
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*/
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/* start out by storing key in pads */
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bzero( k_ipad, sizeof k_ipad);
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bzero( k_opad, sizeof k_opad);
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bcopy( key, k_ipad, key_len);
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bcopy( key, k_opad, key_len);
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/* XOR key with ipad and opad values */
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for (i=0; i<64; i++) {
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k_ipad[i] ^= 0x36;
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k_opad[i] ^= 0x5c;
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}
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/*
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* perform inner MD5
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*/
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MD5Init(&context); /* init context for 1st pass */
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MD5Update(&context, k_ipad, 64); /* start with inner pad */
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MD5Update(&context, text, text_len); /* then text of datagram */
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MD5Final(digest, &context); /* finish up 1st pass */
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/*
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* perform outer MD5
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*/
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MD5Init(&context); /* init context for 2nd
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* pass */
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MD5Update(&context, k_opad, 64); /* start with outer pad */
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MD5Update(&context, digest, 16); /* then results of 1st
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* hash */
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MD5Final(digest, &context); /* finish up 2nd pass */
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}
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