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diff --git a/src/pdkim/pdkim.h b/src/pdkim/pdkim.h
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+/*
+ * PDKIM - a RFC4871 (DKIM) implementation
+ *
+ * Copyright (C) 2009 - 2012 Tom Kistner <tom@duncanthrax.net>
+ * Copyright (c) 2016 - 2020 Jeremy Harris
+ *
+ * http://duncanthrax.net/pdkim/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef PDKIM_H
+#define PDKIM_H
+
+#include "../blob.h"
+#include "../hash.h"
+
+#define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\
+ "Message-ID:To:Cc:MIME-Version:Content-Type:"\
+ "Content-Transfer-Encoding:Content-ID:"\
+ "Content-Description:Resent-Date:Resent-From:"\
+ "Resent-Sender:Resent-To:Resent-Cc:"\
+ "Resent-Message-ID:In-Reply-To:References:"\
+ "List-Id:List-Help:List-Unsubscribe:"\
+ "List-Subscribe:List-Post:List-Owner:List-Archive"
+
+#define PDKIM_OVERSIGN_HEADERS "+From:+Sender:+Reply-To:+Subject:+Date:"\
+ "+Message-ID:+To:+Cc:+MIME-Version:+Content-Type:"\
+ "+Content-Transfer-Encoding:+Content-ID:"\
+ "+Content-Description:+Resent-Date:+Resent-From:"\
+ "+Resent-Sender:+Resent-To:+Resent-Cc:"\
+ "+Resent-Message-ID:+In-Reply-To:+References:"\
+ "+List-Id:+List-Help:+List-Unsubscribe:"\
+ "+List-Subscribe:+List-Post:+List-Owner:+List-Archive"
+
+/* -------------------------------------------------------------------------- */
+/* Length of the preallocated buffer for the "answer" from the dns/txt
+ callback function. This should match the maximum RDLENGTH from DNS. */
+#define PDKIM_DNS_TXT_MAX_RECLEN (1 << 16)
+
+/* -------------------------------------------------------------------------- */
+/* Function success / error codes */
+#define PDKIM_OK 0
+#define PDKIM_FAIL -1
+#define PDKIM_ERR_RSA_PRIVKEY -101
+#define PDKIM_ERR_RSA_SIGNING -102
+#define PDKIM_ERR_LONG_LINE -103
+#define PDKIM_ERR_BUFFER_TOO_SMALL -104
+#define PDKIM_ERR_EXCESS_SIGS -105
+#define PDKIM_SIGN_PRIVKEY_WRAP -106
+#define PDKIM_SIGN_PRIVKEY_B64D -107
+
+/* -------------------------------------------------------------------------- */
+/* Main/Extended verification status */
+#define PDKIM_VERIFY_NONE 0
+#define PDKIM_VERIFY_INVALID 1
+#define PDKIM_VERIFY_FAIL 2
+#define PDKIM_VERIFY_PASS 3
+#define PDKIM_VERIFY_POLICY BIT(31)
+
+#define PDKIM_VERIFY_FAIL_BODY 1
+#define PDKIM_VERIFY_FAIL_MESSAGE 2
+#define PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH 3
+#define PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE 4
+#define PDKIM_VERIFY_INVALID_BUFFER_SIZE 5
+#define PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD 6
+#define PDKIM_VERIFY_INVALID_PUBKEY_IMPORT 7
+#define PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE 8
+#define PDKIM_VERIFY_INVALID_SIGNATURE_ERROR 9
+#define PDKIM_VERIFY_INVALID_DKIM_VERSION 10
+
+/* -------------------------------------------------------------------------- */
+/* Some parameter values */
+#define PDKIM_QUERYMETHOD_DNS_TXT 0
+
+#define PDKIM_CANON_SIMPLE 0
+#define PDKIM_CANON_RELAXED 1
+
+/* -------------------------------------------------------------------------- */
+/* Some required forward declarations, please ignore */
+typedef struct pdkim_stringlist pdkim_stringlist;
+typedef struct pdkim_str pdkim_str;
+typedef struct sha1_context sha1_context;
+typedef struct sha2_context sha2_context;
+#define HAVE_SHA1_CONTEXT
+#define HAVE_SHA2_CONTEXT
+
+/* -------------------------------------------------------------------------- */
+/* Some concessions towards Redmond */
+#ifdef WINDOWS
+#define snprintf _snprintf
+#define strcasecmp _stricmp
+#define strncasecmp _strnicmp
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+
+/* -------------------------------------------------------------------------- */
+/* Public key as (usually) fetched from DNS */
+typedef struct pdkim_pubkey {
+ const uschar * version; /* v= */
+ const uschar *granularity; /* g= */
+
+ const uschar * hashes; /* h= */
+ const uschar * keytype; /* k= */
+ const uschar * srvtype; /* s= */
+ uschar *notes; /* n= */
+
+ blob key; /* p= */
+ int testing; /* t=y */
+ int no_subdomaining; /* t=s */
+} pdkim_pubkey;
+
+/* -------------------------------------------------------------------------- */
+/* Body-hash to be calculated */
+typedef struct pdkim_bodyhash {
+ struct pdkim_bodyhash * next;
+ int hashtype;
+ int canon_method;
+ long bodylength;
+
+ hctx body_hash_ctx;
+ unsigned long signed_body_bytes; /* done so far */
+ int num_buffered_blanklines;
+
+ blob bh; /* completed hash */
+} pdkim_bodyhash;
+
+/* -------------------------------------------------------------------------- */
+/* Signature as it appears in a DKIM-Signature header */
+typedef struct pdkim_signature {
+ struct pdkim_signature * next;
+
+ /* Bits stored in a DKIM signature header --------------------------- */
+
+ /* (v=) The version, as an integer. Currently, always "1" */
+ int version;
+
+ /* (a=) The signature algorithm. */
+ int keytype; /* pdkim_keytypes index */
+ unsigned keybits; /* size of the key */
+ int hashtype; /* pdkim_hashes index */
+
+ /* (c=x/) Header canonicalization method. Either PDKIM_CANON_SIMPLE
+ or PDKIM_CANON_RELAXED */
+ int canon_headers;
+
+ /* (c=/x) Body canonicalization method. Either PDKIM_CANON_SIMPLE
+ or PDKIM_CANON_RELAXED */
+ int canon_body;
+
+ /* (q=) Query Method. Currently, only PDKIM_QUERYMETHOD_DNS_TXT
+ is specified */
+ int querymethod;
+
+ /* (s=) The selector string as given in the signature */
+ uschar *selector;
+
+ /* (d=) The domain as given in the signature */
+ uschar *domain;
+
+ /* (i=) The identity as given in the signature */
+ uschar *identity;
+
+ /* (t=) Timestamp of signature creation */
+ unsigned long created;
+
+ /* (x=) Timestamp of expiry of signature */
+ unsigned long expires;
+
+ /* (l=) Amount of hashed body bytes (after canonicalization). Default
+ is -1. Note: a value of 0 means that the body is unsigned! */
+ long bodylength;
+
+ /* (h=) Colon-separated list of header names that are included in the
+ signature */
+ uschar *headernames;
+
+ /* (z=) */
+ uschar *copiedheaders;
+
+ /* (b=) Raw signature data, along with its length in bytes */
+ blob sighash;
+
+ /* (bh=) Raw body hash data, along with its length in bytes */
+ blob bodyhash;
+
+ /* Folded DKIM-Signature: header. Signing only, NULL for verifying.
+ Ready for insertion into the message. Note: Folded using CRLFTB,
+ but final line terminator is NOT included. Note2: This buffer is
+ free()d when you call pdkim_free_ctx(). */
+ uschar *signature_header;
+
+ /* The main verification status. Verification only. One of:
+
+ PDKIM_VERIFY_NONE Verification was not attempted. This status
+ should not appear.
+
+ PDKIM_VERIFY_INVALID There was an error while trying to verify
+ the signature. A more precise description
+ is available in verify_ext_status.
+
+ PDKIM_VERIFY_FAIL Verification failed because either the body
+ hash did not match, or the signature verification
+ failed. This means the message was modified.
+ Check verify_ext_status for the exact reason.
+
+ PDKIM_VERIFY_PASS Verification succeeded.
+ */
+ int verify_status;
+
+ /* Extended verification status. Verification only. Depending on the value
+ of verify_status, it can contain:
+
+ For verify_status == PDKIM_VERIFY_INVALID:
+
+ PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE
+ Unable to retrieve a public key container.
+
+ PDKIM_VERIFY_INVALID_BUFFER_SIZE
+ Either the DNS name constructed to retrieve the public key record
+ does not fit into PDKIM_DNS_TXT_MAX_NAMELEN bytes, or the retrieved
+ record is longer than PDKIM_DNS_TXT_MAX_RECLEN bytes.
+
+ PDKIM_VERIFY_INVALID_PUBKEY_PARSING
+ (Syntax) error while parsing the retrieved public key record.
+
+
+ For verify_status == PDKIM_VERIFY_FAIL:
+
+ PDKIM_VERIFY_FAIL_BODY
+ The calculated body hash does not match the advertised body hash
+ from the bh= tag of the signature.
+
+ PDKIM_VERIFY_FAIL_MESSAGE
+ RSA verification of the signature (b= tag) failed.
+ */
+ int verify_ext_status;
+
+ /* Pointer to a public key record that was used to verify the signature.
+ See pdkim_pubkey declaration above for more information.
+ Caution: is NULL if signing or if no record was retrieved. */
+ pdkim_pubkey *pubkey;
+
+ /* Properties below this point are used internally only ------------- */
+
+ /* Per-signature helper variables ----------------------------------- */
+ pdkim_bodyhash *calc_body_hash; /* hash to be / being calculated */
+
+ pdkim_stringlist *headers; /* Raw headers included in the sig */
+
+ /* Signing specific ------------------------------------------------- */
+ uschar * privkey; /* Private key */
+ uschar * sign_headers; /* To-be-signed header names */
+ uschar * rawsig_no_b_val; /* Original signature header w/o b= tag value. */
+} pdkim_signature;
+
+
+/* -------------------------------------------------------------------------- */
+/* Context to keep state between all operations. */
+typedef struct pdkim_ctx {
+
+#define PDKIM_MODE_SIGN BIT(0) /* if unset, mode==verify */
+#define PDKIM_DOT_TERM BIT(1) /* dot termination and unstuffing */
+#define PDKIM_SEEN_CR BIT(2)
+#define PDKIM_SEEN_LF BIT(3)
+#define PDKIM_PAST_HDRS BIT(4)
+#define PDKIM_SEEN_EOD BIT(5)
+ unsigned flags;
+
+ /* One (signing) or several chained (verification) signatures */
+ pdkim_signature *sig;
+
+ /* One (signing) or several chained (verification) bodyhashes */
+ pdkim_bodyhash *bodyhash;
+
+ /* Callback for dns/txt query method (verification only) */
+ uschar * (*dns_txt_callback)(const uschar *);
+
+ /* Coder's little helpers */
+ gstring *cur_header;
+ uschar *linebuf;
+ int linebuf_offset;
+ int num_headers;
+ pdkim_stringlist *headers; /* Raw headers for verification */
+} pdkim_ctx;
+
+
+/******************************************************************************/
+
+typedef struct {
+ const uschar * dkim_hashname;
+ hashmethod exim_hashmethod;
+} pdkim_hashtype;
+extern const pdkim_hashtype pdkim_hashes[];
+
+/******************************************************************************/
+
+
+/* -------------------------------------------------------------------------- */
+/* API functions. Please see the sample code in sample/test_sign.c and
+ sample/test_verify.c for documentation.
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void pdkim_init (void);
+
+void pdkim_init_context (pdkim_ctx *, BOOL, uschar * (*)(const uschar *));
+
+DLLEXPORT
+pdkim_signature *pdkim_init_sign (pdkim_ctx *,
+ uschar *, uschar *, uschar *, uschar *,
+ const uschar **);
+
+DLLEXPORT
+pdkim_ctx *pdkim_init_verify (uschar * (*)(const uschar *), BOOL);
+
+DLLEXPORT
+void pdkim_set_optional (pdkim_signature *, char *, char *,int, int,
+ long,
+ unsigned long,
+ unsigned long);
+
+int pdkim_hashname_to_hashtype(const uschar *, unsigned);
+void pdkim_cstring_to_canons(const uschar *, unsigned, int *, int *);
+pdkim_bodyhash *pdkim_set_bodyhash(pdkim_ctx *, int, int, long);
+pdkim_bodyhash *pdkim_set_sig_bodyhash(pdkim_ctx *, pdkim_signature *);
+
+DLLEXPORT
+int pdkim_feed (pdkim_ctx *, uschar *, int);
+DLLEXPORT
+int pdkim_feed_finish (pdkim_ctx *, pdkim_signature **, const uschar **);
+
+DLLEXPORT
+void pdkim_free_ctx (pdkim_ctx *);
+
+
+const uschar * pdkim_errstr(int);
+
+extern uschar * pdkim_encode_base64(blob *);
+extern void pdkim_decode_base64(const uschar *, blob *);
+extern void pdkim_hexprint(const uschar *, int);
+extern void pdkim_quoteprint(const uschar *, int);
+extern pdkim_pubkey * pdkim_parse_pubkey_record(const uschar *);
+extern uschar * pdkim_relax_header_n(const uschar *, int, BOOL);
+extern uschar * pdkim_relax_header(const uschar *, BOOL);
+extern uschar * dkim_sig_to_a_tag(const pdkim_signature *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif