X-Git-Url: https://vcs.fsf.org/?p=exim.git;a=blobdiff_plain;f=src%2Fsrc%2Fpdkim%2Fpdkim.c;h=441f96cb55b2217cac5c4b54fa8aedfad65e6d23;hp=f3959cdc7339c8e64993f4d68044f844a6ff4410;hb=9b2583c440ab9104070054dfa02e8611799f777b;hpb=c2f669a4994192344613569e198c7b503d46d45e diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c index f3959cdc7..441f96cb5 100644 --- a/src/src/pdkim/pdkim.c +++ b/src/src/pdkim/pdkim.c @@ -2,7 +2,7 @@ * PDKIM - a RFC4871 (DKIM) implementation * * Copyright (C) 2009 - 2016 Tom Kistner - * Copyright (C) 2016 Jeremy Harris + * Copyright (C) 2016 - 2017 Jeremy Harris * * http://duncanthrax.net/pdkim/ * @@ -42,10 +42,10 @@ #endif #include "pdkim.h" -#include "rsa.h" +#include "signing.h" #define PDKIM_SIGNATURE_VERSION "1" -#define PDKIM_PUB_RECORD_VERSION "DKIM1" +#define PDKIM_PUB_RECORD_VERSION US "DKIM1" #define PDKIM_MAX_HEADER_LEN 65536 #define PDKIM_MAX_HEADERS 512 @@ -62,51 +62,53 @@ /* -------------------------------------------------------------------------- */ struct pdkim_stringlist { - char *value; - int tag; - void *next; + uschar * value; + int tag; + void * next; }; /* -------------------------------------------------------------------------- */ /* A bunch of list constants */ -const char *pdkim_querymethods[] = { - "dns/txt", +const uschar * pdkim_querymethods[] = { + US"dns/txt", NULL }; -const char *pdkim_algos[] = { - "rsa-sha256", - "rsa-sha1", +const uschar * pdkim_algos[] = { + US"rsa-sha256", + US"rsa-sha1", NULL }; -const char *pdkim_canons[] = { - "simple", - "relaxed", +const uschar * pdkim_canons[] = { + US"simple", + US"relaxed", NULL }; -const char *pdkim_hashes[] = { - "sha256", - "sha1", +/*XXX currently unused */ +const uschar * pdkim_hashes[] = { + US"sha256", + US"sha1", NULL }; -const char *pdkim_keytypes[] = { - "rsa", +/*XXX currently unused */ +const uschar * pdkim_keytypes[] = { + US"rsa", NULL }; typedef struct pdkim_combined_canon_entry { - const char *str; + const uschar * str; int canon_headers; int canon_body; } pdkim_combined_canon_entry; pdkim_combined_canon_entry pdkim_combined_canons[] = { - { "simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, - { "simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, - { "relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, - { "relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, - { "simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, - { "relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, - { NULL, 0, 0 } + { US"simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, + { US"simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, + { US"relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, + { US"relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, + { US"simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, + { US"relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, + { NULL, 0, 0 } }; @@ -115,26 +117,48 @@ pdkim_combined_canon_entry pdkim_combined_canons[] = { const char * pdkim_verify_status_str(int status) { - switch(status) { - case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; - case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; - case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; - case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; - default: return "PDKIM_VERIFY_UNKNOWN"; +switch(status) + { + case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; + case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; + case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; + case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; + default: return "PDKIM_VERIFY_UNKNOWN"; } } const char * pdkim_verify_ext_status_str(int ext_status) { - switch(ext_status) { - case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; - case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; - case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; - case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; - case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD"; - case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT"; - default: return "PDKIM_VERIFY_UNKNOWN"; +switch(ext_status) + { + case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; + case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; + case PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH: return "PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH"; + case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; + case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; + case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD"; + case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT"; + case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR"; + case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION"; + default: return "PDKIM_VERIFY_UNKNOWN"; + } +} + +const uschar * +pdkim_errstr(int status) +{ +switch(status) + { + case PDKIM_OK: return US"OK"; + case PDKIM_FAIL: return US"FAIL"; + case PDKIM_ERR_RSA_PRIVKEY: return US"RSA_PRIVKEY"; + case PDKIM_ERR_RSA_SIGNING: return US"RSA SIGNING"; + case PDKIM_ERR_LONG_LINE: return US"RSA_LONG_LINE"; + case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL"; + case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP"; + case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D"; + default: return US"(unknown)"; } } @@ -171,7 +195,8 @@ static void pdkim_hexprint(const uschar *data, int len) { int i; -for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]); +if (data) for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]); +else debug_printf(""); debug_printf("\n"); } @@ -224,7 +249,7 @@ pdkim_free_ctx(pdkim_ctx *ctx) /*XXX might be safer done using a pdkim_stringlist for "tick" */ static int -header_name_match(const uschar * header, char * tick) +header_name_match(const uschar * header, uschar * tick) { uschar * hname; uschar * lcopy; @@ -266,7 +291,7 @@ found: /* Performs "relaxed" canonicalization of a header. */ static uschar * -pdkim_relax_header(const uschar * header, int crlf) +pdkim_relax_header(const uschar * header, BOOL append_crlf) { BOOL past_field_name = FALSE; BOOL seen_wsp = FALSE; @@ -277,8 +302,8 @@ uschar * q = relaxed; for (p = header; *p; p++) { uschar c = *p; - /* Ignore CR & LF */ - if (c == '\r' || c == '\n') + + if (c == '\r' || c == '\n') /* Ignore CR & LF */ continue; if (c == '\t' || c == ' ') { @@ -290,8 +315,8 @@ for (p = header; *p; p++) else if (!past_field_name && c == ':') { - if (seen_wsp) q--; /* This removes WSP before the colon */ - seen_wsp = TRUE; /* This removes WSP after the colon */ + if (seen_wsp) q--; /* This removes WSP immediately before the colon */ + seen_wsp = TRUE; /* This removes WSP immediately after the colon */ past_field_name = TRUE; } else @@ -304,7 +329,7 @@ for (p = header; *p; p++) if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */ -if (crlf) { *q++ = '\r'; *q++ = '\n'; } +if (append_crlf) { *q++ = '\r'; *q++ = '\n'; } *q = '\0'; return relaxed; } @@ -313,10 +338,10 @@ return relaxed; /* -------------------------------------------------------------------------- */ #define PDKIM_QP_ERROR_DECODE -1 -static char * -pdkim_decode_qp_char(char *qp_p, int *c) +static const uschar * +pdkim_decode_qp_char(const uschar *qp_p, int *c) { -char *initial_pos = qp_p; +const uschar *initial_pos = qp_p; /* Advance one char */ qp_p++; @@ -338,12 +363,12 @@ return initial_pos; /* -------------------------------------------------------------------------- */ -static char * -pdkim_decode_qp(uschar * str) +static uschar * +pdkim_decode_qp(const uschar * str) { int nchar = 0; uschar * q; -uschar * p = str; +const uschar * p = str; uschar * n = store_get(Ustrlen(str)+1); *n = '\0'; @@ -371,7 +396,7 @@ return n; /* -------------------------------------------------------------------------- */ static void -pdkim_decode_base64(uschar *str, blob * b) +pdkim_decode_base64(const uschar * str, blob * b) { int dlen; dlen = b64decode(str, &b->data); @@ -394,7 +419,7 @@ return b64encode(b->data, b->len); static pdkim_signature * pdkim_parse_sig_header(pdkim_ctx *ctx, uschar * raw_hdr) { -pdkim_signature *sig ; +pdkim_signature * sig; uschar *p, *q; uschar * cur_tag = NULL; int ts = 0, tl = 0; uschar * cur_val = NULL; int vs = 0, vl = 0; @@ -407,6 +432,10 @@ sig = store_get(sizeof(pdkim_signature)); memset(sig, 0, sizeof(pdkim_signature)); sig->bodylength = -1; +/* Set so invalid/missing data error display is accurate */ +sig->algo = -1; +sig->version = 0; + q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1); for (p = raw_hdr; ; p++) @@ -468,18 +497,17 @@ for (p = raw_hdr; ; p++) switch (*cur_tag) { case 'b': - if (cur_tag[1] == 'h') - pdkim_decode_base64(cur_val, &sig->bodyhash); - else - pdkim_decode_base64(cur_val, &sig->sigdata); + pdkim_decode_base64(cur_val, + cur_tag[1] == 'h' ? &sig->bodyhash : &sig->sighash); break; case 'v': /* We only support version 1, and that is currently the only version there is. */ - if (Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0) - sig->version = 1; + sig->version = + Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; break; case 'a': +/*XXX this searches a list of combined (algo + hash-method)s */ for (i = 0; pdkim_algos[i]; i++) if (Ustrcmp(cur_val, pdkim_algos[i]) == 0) { @@ -542,10 +570,6 @@ NEXT_CHAR: *q++ = c; } -/* Make sure the most important bits are there. */ -if (!sig->version) - return NULL; - *q = '\0'; /* Chomp raw header. The final newline must not be added to the signature. */ while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n')) @@ -555,14 +579,20 @@ DEBUG(D_acl) { debug_printf( "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); - pdkim_quoteprint(US sig->rawsig_no_b_val, strlen(sig->rawsig_no_b_val)); + pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val)); debug_printf( - "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sigdata.len*8); + "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8); debug_printf( "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); } -exim_sha_init(&sig->body_hash, sig->algo == PDKIM_ALGO_RSA_SHA1); +/*XXX hash method: extend for sha512 */ +if (!exim_sha_init(&sig->body_hash_ctx, + sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hash init internal error\n"); + return NULL; + } return sig; } @@ -570,108 +600,60 @@ return sig; /* -------------------------------------------------------------------------- */ static pdkim_pubkey * -pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record) +pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record) { -pdkim_pubkey *pub; -char *p; -uschar * cur_tag = NULL; int ts = 0, tl = 0; -uschar * cur_val = NULL; int vs = 0, vl = 0; -int where = PDKIM_HDR_LIMBO; +const uschar * ele; +int sep = ';'; +pdkim_pubkey * pub; pub = store_get(sizeof(pdkim_pubkey)); memset(pub, 0, sizeof(pdkim_pubkey)); -for (p = raw_record; ; p++) +while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0))) { - char c = *p; + const uschar * val; - /* Ignore FWS */ - if (c == '\r' || c == '\n') - goto NEXT_CHAR; - - if (where == PDKIM_HDR_LIMBO) + if ((val = Ustrchr(ele, '='))) { - /* In limbo, just wait for a tag-char to appear */ - if (!(c >= 'a' && c <= 'z')) - goto NEXT_CHAR; + int taglen = val++ - ele; - where = PDKIM_HDR_TAG; - } - - if (where == PDKIM_HDR_TAG) - { - if (c >= 'a' && c <= 'z') - cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); - - if (c == '=') + DEBUG(D_acl) debug_printf(" %.*s=%s\n", taglen, ele, val); + switch (ele[0]) { - cur_tag[tl] = '\0'; - where = PDKIM_HDR_VALUE; - goto NEXT_CHAR; - } - } - - if (where == PDKIM_HDR_VALUE) - { - if (c == ';' || c == '\0') - { - if (tl && vl) - { - cur_val[vl] = '\0'; - pdkim_strtrim(cur_val); - DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); - - switch (cur_tag[0]) - { - case 'v': - /* This tag isn't evaluated because: - - We only support version DKIM1. - - Which is the default for this value (set below) - - Other versions are currently not specified. */ - break; - case 'h': - case 'k': - pub->hashes = string_copy(cur_val); break; - case 'g': - pub->granularity = string_copy(cur_val); break; - case 'n': - pub->notes = pdkim_decode_qp(cur_val); break; - case 'p': - pdkim_decode_base64(US cur_val, &pub->key); - break; - case 's': - pub->srvtype = string_copy(cur_val); break; - case 't': - if (strchr(cur_val, 'y') != NULL) pub->testing = 1; - if (strchr(cur_val, 's') != NULL) pub->no_subdomaining = 1; - break; - default: - DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); - break; - } - } - tl = 0; - vl = 0; - where = PDKIM_HDR_LIMBO; + case 'v': pub->version = val; break; + case 'h': pub->hashes = val; break; + case 'k': break; + case 'g': pub->granularity = val; break; + case 'n': pub->notes = pdkim_decode_qp(val); break; + case 'p': pdkim_decode_base64(val, &pub->key); break; + case 's': pub->srvtype = val; break; + case 't': if (Ustrchr(val, 'y')) pub->testing = 1; + if (Ustrchr(val, 's')) pub->no_subdomaining = 1; + break; + default: DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); break; } - else - cur_val = string_catn(cur_val, &vs, &vl, p, 1); } - -NEXT_CHAR: - if (c == '\0') break; } /* Set fallback defaults */ if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION); -if (!pub->granularity) pub->granularity = string_copy(US"*"); -if (!pub->keytype ) pub->keytype = string_copy("rsa"); -if (!pub->srvtype ) pub->srvtype = string_copy(US"*"); +else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0) + { + DEBUG(D_acl) debug_printf(" Bad v= field\n"); + return NULL; + } + +if (!pub->granularity) pub->granularity = US"*"; +/* +if (!pub->keytype ) pub->keytype = US"rsa"; +*/ +if (!pub->srvtype ) pub->srvtype = US"*"; /* p= is required */ if (pub->key.data) return pub; +DEBUG(D_acl) debug_printf(" Missing p= field\n"); return NULL; } @@ -679,15 +661,14 @@ return NULL; /* -------------------------------------------------------------------------- */ static int -pdkim_update_bodyhash(pdkim_ctx *ctx, const char *data, int len) +pdkim_update_bodyhash(pdkim_ctx * ctx, const char * data, int len) { -pdkim_signature *sig = ctx->sig; -/* Cache relaxed version of data */ -uschar *relaxed_data = NULL; -int relaxed_len = 0; +pdkim_signature * sig; +uschar * relaxed_data = NULL; /* Cache relaxed version of data */ +int relaxed_len = 0; /* Traverse all signatures, updating their hashes. */ -while (sig) +for (sig = ctx->sig; sig; sig = sig->next) { /* Defaults to simple canon (no further treatment necessary) */ const uschar *canon_data = CUS data; @@ -702,7 +683,12 @@ while (sig) const char *p; int q = 0; - relaxed_data = store_get(len+1); + /* We want to be able to free this else we allocate + for the entire message which could be many MB. Since + we don't know what allocations the SHA routines might + do, not safe to use store_get()/store_reset(). */ + + relaxed_data = store_malloc(len+1); for (p = data; *p; p++) { @@ -738,14 +724,13 @@ while (sig) if (canon_len > 0) { - exim_sha_update(&sig->body_hash, CCS canon_data, canon_len); + exim_sha_update(&sig->body_hash_ctx, CUS canon_data, canon_len); sig->signed_body_bytes += canon_len; DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len); } - - sig = sig->next; } +if (relaxed_data) store_free(relaxed_data); return PDKIM_OK; } @@ -762,18 +747,18 @@ for (sig = ctx->sig; sig; sig = sig->next) { /* Finish hashes */ blob bh; - exim_sha_finish(&sig->body_hash, &bh); + exim_sha_finish(&sig->body_hash_ctx, &bh); DEBUG(D_acl) { debug_printf("PDKIM [%s] Body bytes hashed: %lu\n" - "PDKIM [%s] bh computed: ", + "PDKIM [%s] Body hash computed: ", sig->domain, sig->signed_body_bytes, sig->domain); pdkim_hexprint(CUS bh.data, bh.len); } /* SIGNING -------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) + if (ctx->flags & PDKIM_MODE_SIGN) { sig->bodyhash = bh; @@ -783,11 +768,11 @@ for (sig = ctx->sig; sig; sig = sig->next) sig->bodylength = -1; } - /* VERIFICATION --------------------------------------------------------- */ else - { - /* Compare bodyhash */ - if (memcmp(bh.data, sig->bodyhash.data, bh.len) == 0) + /* VERIFICATION --------------------------------------------------------- */ + /* Be careful that the header sig included a bodyash */ + + if (sig->bodyhash.data && memcmp(bh.data, sig->bodyhash.data, bh.len) == 0) { DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain); } @@ -795,22 +780,44 @@ for (sig = ctx->sig; sig; sig = sig->next) { DEBUG(D_acl) { - debug_printf("PDKIM [%s] bh signature: ", sig->domain); - pdkim_hexprint(sig->bodyhash.data, - exim_sha_hashlen(&sig->body_hash)); + debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain); + pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len); debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain); } sig->verify_status = PDKIM_VERIFY_FAIL; sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY; } - } } } +static int +pdkim_body_complete(pdkim_ctx * ctx) +{ +pdkim_signature * sig = ctx->sig; /*XXX assumes only one sig */ + +/* In simple body mode, if any empty lines were buffered, +replace with one. rfc 4871 3.4.3 */ +/*XXX checking the signed-body-bytes is a gross hack; I think +it indicates that all linebreaks should be buffered, including +the one terminating a text line */ + +if ( sig && sig->canon_body == PDKIM_CANON_SIMPLE + && sig->signed_body_bytes == 0 + && ctx->num_buffered_crlf > 0 + ) + pdkim_update_bodyhash(ctx, "\r\n", 2); + +ctx->flags |= PDKIM_SEEN_EOD; +ctx->linebuf_offset = 0; +return PDKIM_OK; +} + + + /* -------------------------------------------------------------------------- */ -/* Callback from pdkim_feed below for processing complete body lines */ +/* Call from pdkim_feed below for processing complete body lines */ static int pdkim_bodyline_complete(pdkim_ctx *ctx) @@ -820,33 +827,23 @@ int n = ctx->linebuf_offset; pdkim_signature *sig = ctx->sig; /*XXX assumes only one sig */ /* Ignore extra data if we've seen the end-of-data marker */ -if (ctx->seen_eod) goto BAIL; +if (ctx->flags & PDKIM_SEEN_EOD) goto BAIL; /* We've always got one extra byte to stuff a zero ... */ ctx->linebuf[ctx->linebuf_offset] = '\0'; /* Terminate on EOD marker */ -if (memcmp(p, ".\r\n", 3) == 0) +if (ctx->flags & PDKIM_DOT_TERM) { - /* In simple body mode, if any empty lines were buffered, - replace with one. rfc 4871 3.4.3 */ - /*XXX checking the signed-body-bytes is a gross hack; I think - it indicates that all linebreaks should be buffered, including - the one terminating a text line */ - if ( sig && sig->canon_body == PDKIM_CANON_SIMPLE - && sig->signed_body_bytes == 0 - && ctx->num_buffered_crlf > 0 - ) - pdkim_update_bodyhash(ctx, "\r\n", 2); + if (memcmp(p, ".\r\n", 3) == 0) + return pdkim_body_complete(ctx); - ctx->seen_eod = TRUE; - goto BAIL; - } -/* Unstuff dots */ -if (memcmp(p, "..", 2) == 0) - { - p++; - n--; + /* Unstuff dots */ + if (memcmp(p, "..", 2) == 0) + { + p++; + n--; + } } /* Empty lines need to be buffered until we find a non-empty line */ @@ -894,68 +891,65 @@ return PDKIM_OK; #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" static int -pdkim_header_complete(pdkim_ctx *ctx) +pdkim_header_complete(pdkim_ctx * ctx) { +pdkim_signature * sig, * last_sig; + /* Special case: The last header can have an extra \r appended */ if ( (ctx->cur_header_len > 1) && (ctx->cur_header[(ctx->cur_header_len)-1] == '\r') ) --ctx->cur_header_len; ctx->cur_header[ctx->cur_header_len] = '\0'; -ctx->num_headers++; -if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; +if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; /* SIGNING -------------------------------------------------------------- */ -if (ctx->mode == PDKIM_MODE_SIGN) - { - pdkim_signature *sig; - +if (ctx->flags & PDKIM_MODE_SIGN) for (sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */ /* Add header to the signed headers list (in reverse order) */ sig->headers = pdkim_prepend_stringlist(sig->headers, ctx->cur_header); - } /* VERIFICATION ----------------------------------------------------------- */ /* DKIM-Signature: headers are added to the verification list */ -if (ctx->mode == PDKIM_MODE_VERIFY) +else { - if (strncasecmp(ctx->cur_header, +#ifdef notdef + DEBUG(D_acl) + { + debug_printf("PDKIM >> raw hdr: "); + pdkim_quoteprint(CUS ctx->cur_header, ctx->cur_header_len); + } +#endif + if (strncasecmp(CCS ctx->cur_header, DKIM_SIGNATURE_HEADERNAME, - strlen(DKIM_SIGNATURE_HEADERNAME)) == 0) + Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0) { - pdkim_signature *new_sig; + /* Create and chain new signature block. We could error-check for all + required tags here, but prefer to create the internal sig and expicitly + fail verification of it later. */ - /* Create and chain new signature block */ DEBUG(D_acl) debug_printf( "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); - if ((new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header))) + sig = pdkim_parse_sig_header(ctx, ctx->cur_header); + + if (!(last_sig = ctx->sig)) + ctx->sig = sig; + else { - pdkim_signature *last_sig = ctx->sig; - if (!last_sig) - ctx->sig = new_sig; - else - { - while (last_sig->next) last_sig = last_sig->next; - last_sig->next = new_sig; - } + while (last_sig->next) last_sig = last_sig->next; + last_sig->next = sig; } - else - DEBUG(D_acl) debug_printf( - "Error while parsing signature header\n" - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); } - /* every other header is stored for signature verification */ - else - ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header); + /* all headers are stored for signature verification */ + ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header); } BAIL: -*ctx->cur_header = '\0'; -ctx->cur_header_len = 0; /* leave buffer for reuse */ +ctx->cur_header[ctx->cur_header_len = 0] = '\0'; /* leave buffer for reuse */ return PDKIM_OK; } @@ -965,61 +959,76 @@ return PDKIM_OK; #define HEADER_BUFFER_FRAG_SIZE 256 DLLEXPORT int -pdkim_feed(pdkim_ctx *ctx, char *data, int len) +pdkim_feed(pdkim_ctx * ctx, uschar * data, int len) { -int p; +int p, rc; -for (p = 0; ppast_headers) + if (ctx->flags & PDKIM_PAST_HDRS) { + if (c == '\n' && !(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ + { + ctx->linebuf[ctx->linebuf_offset++] = '\r'; + if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) + return PDKIM_ERR_LONG_LINE; + } + /* Processing body byte */ ctx->linebuf[ctx->linebuf_offset++] = c; - if (c == '\n') + if (c == '\r') + ctx->flags |= PDKIM_SEEN_CR; + else if (c == '\n') { - int rc = pdkim_bodyline_complete(ctx); /* End of line */ - if (rc != PDKIM_OK) return rc; + ctx->flags &= ~PDKIM_SEEN_CR; + if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK) + return rc; } - if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1)) + + if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) return PDKIM_ERR_LONG_LINE; } else { /* Processing header byte */ - if (c != '\r') + if (c == '\r') + ctx->flags |= PDKIM_SEEN_CR; + else if (c == '\n') { - if (c == '\n') - { - if (ctx->seen_lf) - { - int rc = pdkim_header_complete(ctx); /* Seen last header line */ - if (rc != PDKIM_OK) return rc; - - ctx->past_headers = TRUE; - ctx->seen_lf = 0; - DEBUG(D_acl) debug_printf( - "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>\n"); - continue; - } - else - ctx->seen_lf = TRUE; - } - else if (ctx->seen_lf) - { - if (!(c == '\t' || c == ' ')) - { - int rc = pdkim_header_complete(ctx); /* End of header */ - if (rc != PDKIM_OK) return rc; - } - ctx->seen_lf = FALSE; + if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ + ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, + &ctx->cur_header_len, CUS "\r", 1); + + if (ctx->flags & PDKIM_SEEN_LF) /* Seen last header line */ + { + if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) + return rc; + + ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS; + DEBUG(D_acl) debug_printf( + "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + continue; } + else + ctx->flags = (ctx->flags & ~PDKIM_SEEN_CR) | PDKIM_SEEN_LF; + } + else if (ctx->flags & PDKIM_SEEN_LF) + { + if (!(c == '\t' || c == ' ')) /* End of header */ + if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) + return rc; + ctx->flags &= ~PDKIM_SEEN_LF; } if (ctx->cur_header_len < PDKIM_MAX_HEADER_LEN) ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, - &ctx->cur_header_len, &data[p], 1); + &ctx->cur_header_len, CUS &data[p], 1); } } return PDKIM_OK; @@ -1175,11 +1184,12 @@ canon_all = string_cat (canon_all, &can_size, &can_len, canon_all[can_len] = '\0'; hdr = string_cat(NULL, &hdr_size, &hdr_len, - "DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); + US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); col = hdr_len; /* Required and static bits */ hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=", +/*XXX this is a combo of algo and hash-method */ pdkim_algos[sig->algo]); hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"q=", pdkim_querymethods[sig->querymethod]); @@ -1192,7 +1202,7 @@ hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"s=", /* list of header names can be split between items. */ { - uschar * n = CS string_copy(sig->headernames); + uschar * n = string_copy(sig->headernames); uschar * i = US"h="; uschar * s = US";"; @@ -1225,48 +1235,127 @@ if (sig->identity) if (sig->created > 0) { - char minibuf[20]; + uschar minibuf[20]; - snprintf(minibuf, 20, "%lu", sig->created); + snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created); hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"t=", minibuf); } if (sig->expires > 0) { - char minibuf[20]; + uschar minibuf[20]; - snprintf(minibuf, 20, "%lu", sig->expires); + snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires); hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"x=", minibuf); } if (sig->bodylength >= 0) { - char minibuf[20]; + uschar minibuf[20]; - snprintf(minibuf, 20, "%lu", sig->bodylength); + snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength); hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"l=", minibuf); } /* Preliminary or final version? */ -base64_b = final ? pdkim_encode_base64(&sig->sigdata) : US""; -hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=", base64_b); +if (final) + { + base64_b = pdkim_encode_base64(&sig->sighash); + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=", base64_b); -/* add trailing semicolon: I'm not sure if this is actually needed */ -hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US""); + /* add trailing semicolon: I'm not sure if this is actually needed */ + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US""); + } +else + { + /* To satisfy the rule "all surrounding whitespace [...] deleted" + ( RFC 6376 section 3.7 ) we ensure there is no whitespace here. Otherwise + the headcat routine could insert a linebreak which the relaxer would reduce + to a single space preceding the terminating semicolon, resulting in an + incorrect header-hash. */ + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=;", US""); + } hdr[hdr_len] = '\0'; return hdr; } +/* -------------------------------------------------------------------------- */ + +static pdkim_pubkey * +pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx, + const uschar ** errstr) +{ +uschar * dns_txt_name, * dns_txt_reply; +pdkim_pubkey * p; + +/* Fetch public key for signing domain, from DNS */ + +dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain); + +dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN); +memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN); + +if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK + || dns_txt_reply[0] == '\0' + ) + { + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; + return NULL; + } + +DEBUG(D_acl) + { + debug_printf( + "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" + " Raw record: "); + pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); + } + +if ( !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply)) + || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0) + ) + { + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD; + + DEBUG(D_acl) + { + if (p) + debug_printf(" Invalid public key service type '%s'\n", p->srvtype); + else + debug_printf(" Error while parsing public key record\n"); + debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + } + return NULL; + } + +DEBUG(D_acl) debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + +/* Import public key */ +if ((*errstr = exim_dkim_verify_init(&p->key, vctx))) + { + DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr); + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; + return NULL; + } + +return p; +} + + /* -------------------------------------------------------------------------- */ DLLEXPORT int -pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) +pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures, + const uschar ** err) { pdkim_signature *sig = ctx->sig; -uschar * headernames = NULL; /* Collected signed header names */ -int hs = 0, hl = 0; /* Check if we must still flush a (partial) header. If that is the case, the message has no body, and we must compute a body hash @@ -1286,9 +1375,10 @@ pdkim_finish_bodyhash(ctx); while (sig) { +/*XXX bool probably not enough */ BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1; hctx hhash_ctx; - uschar * sig_hdr; + uschar * sig_hdr = US""; blob hhash; blob hdata; int hdata_alloc = 0; @@ -1296,10 +1386,14 @@ while (sig) hdata.data = NULL; hdata.len = 0; - exim_sha_init(&hhash_ctx, is_sha1); + if (!exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hask setup internal error\n"); + break; + } DEBUG(D_acl) debug_printf( - "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n"); + "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>\n"); /* SIGNING ---------------------------------------------------------------- */ /* When signing, walk through our header list and add them to the hash. As we @@ -1307,8 +1401,10 @@ while (sig) Then append to that list any remaining header names for which there was no header to sign. */ - if (ctx->mode == PDKIM_MODE_SIGN) + if (ctx->flags & PDKIM_MODE_SIGN) { + uschar * headernames = NULL; /* Collected signed header names */ + int hs = 0, hl = 0; pdkim_stringlist *p; const uschar * l; uschar * s; @@ -1325,14 +1421,14 @@ while (sig) p->value, (q - US p->value) + (p->next ? 1 : 0)); rh = sig->canon_headers == PDKIM_CANON_RELAXED - ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */ + ? pdkim_relax_header(p->value, TRUE) /* cook header for relaxed canon */ : string_copy(CUS p->value); /* just copy it for simple canon */ /* Feed header to the hash algorithm */ - exim_sha_update(&hhash_ctx, CCS rh, Ustrlen(rh)); + exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); /* Remember headers block for signing (when the library cannot do incremental) */ - (void) exim_rsa_data_append(&hdata, &hdata_alloc, rh); + (void) exim_dkim_data_append(&hdata, &hdata_alloc, rh); DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); } @@ -1350,7 +1446,6 @@ while (sig) /* Copy headernames to signature struct */ sig->headernames = headernames; - headernames = NULL, hs = hl = 0; /* Create signature header with b= omitted */ sig_hdr = pdkim_create_header(sig, FALSE); @@ -1361,44 +1456,49 @@ while (sig) add the headers to the hash in that order. */ else { - uschar * b = string_copy(sig->headernames); - uschar * p = b; + uschar * p = sig->headernames; uschar * q; pdkim_stringlist * hdrs; - /* clear tags */ - for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) - hdrs->tag = 0; - - while(1) + if (p) { - if ((q = Ustrchr(p, ':'))) - *q = '\0'; - -/*XXX walk the list of headers in same order as received. */ + /* clear tags */ for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) - if ( hdrs->tag == 0 - && strncasecmp(hdrs->value, CS p, Ustrlen(p)) == 0 - && (hdrs->value)[Ustrlen(p)] == ':' - ) - { - uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED - ? pdkim_relax_header(hdrs->value, 1) /* cook header for relaxed canon */ - : string_copy(CUS hdrs->value); /* just copy it for simple canon */ + hdrs->tag = 0; - /* Feed header to the hash algorithm */ - exim_sha_update(&hhash_ctx, CCS rh, Ustrlen(rh)); + p = string_copy(p); + while(1) + { + if ((q = Ustrchr(p, ':'))) + *q = '\0'; + + /*XXX walk the list of headers in same order as received. */ + for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) + if ( hdrs->tag == 0 + && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0 + && (hdrs->value)[Ustrlen(p)] == ':' + ) + { + /* cook header for relaxed canon, or just copy it for simple */ + + uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED + ? pdkim_relax_header(hdrs->value, TRUE) + : string_copy(CUS hdrs->value); + + /* Feed header to the hash algorithm */ + exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); + + DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); + hdrs->tag = 1; + break; + } - DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); - hdrs->tag = 1; - break; - } + if (!q) break; + p = q+1; + } - if (!q) break; - p = q+1; + sig_hdr = string_copy(sig->rawsig_no_b_val); } - - sig_hdr = string_copy(sig->rawsig_no_b_val); } DEBUG(D_acl) debug_printf( @@ -1406,41 +1506,42 @@ while (sig) /* Relax header if necessary */ if (sig->canon_headers == PDKIM_CANON_RELAXED) - sig_hdr = pdkim_relax_header(sig_hdr, 0); + sig_hdr = pdkim_relax_header(sig_hdr, FALSE); DEBUG(D_acl) { debug_printf( "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n"); - pdkim_quoteprint(CUS sig_hdr, strlen(sig_hdr)); + pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); debug_printf( "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); } /* Finalize header hash */ - exim_sha_update(&hhash_ctx, sig_hdr, strlen(sig_hdr)); + exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr)); exim_sha_finish(&hhash_ctx, &hhash); DEBUG(D_acl) { - debug_printf("PDKIM [%s] hh computed: ", sig->domain); + debug_printf("PDKIM [%s] Header hash computed: ", sig->domain); pdkim_hexprint(hhash.data, hhash.len); } /* Remember headers block for signing (when the library cannot do incremental) */ - if (ctx->mode == PDKIM_MODE_SIGN) - (void) exim_rsa_data_append(&hdata, &hdata_alloc, US sig_hdr); +/*XXX is this assuing algo == RSA? */ + if (ctx->flags & PDKIM_MODE_SIGN) + (void) exim_dkim_data_append(&hdata, &hdata_alloc, US sig_hdr); /* SIGNING ---------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) + if (ctx->flags & PDKIM_MODE_SIGN) { es_ctx sctx; - const uschar * errstr; /* Import private key */ - if ((errstr = exim_rsa_signing_init(US sig->rsa_privkey, &sctx))) +/*XXX extend for non-RSA algos */ + if ((*err = exim_dkim_signing_init(US sig->rsa_privkey, &sctx))) { - DEBUG(D_acl) debug_printf("signing_init: %s\n", errstr); + DEBUG(D_acl) debug_printf("signing_init: %s\n", *err); return PDKIM_ERR_RSA_PRIVKEY; } @@ -1452,16 +1553,20 @@ while (sig) hdata = hhash; #endif - if ((errstr = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sigdata))) +/*XXX extend for non-RSA algos */ +/*XXX oddly the dkim rfc does _not_ say what variant (sha1 or sha256) of +RSA signing should be done. We use the same variant as the hash-method. */ + + if ((*err = exim_dkim_sign(&sctx, is_sha1, &hdata, &sig->sighash))) { - DEBUG(D_acl) debug_printf("signing: %s\n", errstr); + DEBUG(D_acl) debug_printf("signing: %s\n", *err); return PDKIM_ERR_RSA_SIGNING; } DEBUG(D_acl) { debug_printf( "PDKIM [%s] b computed: ", sig->domain); - pdkim_hexprint(sig->sigdata.data, sig->sigdata.len); + pdkim_hexprint(sig->sighash.data, sig->sighash.len); } sig->signature_header = pdkim_create_header(sig, TRUE); @@ -1471,68 +1576,72 @@ while (sig) else { ev_ctx vctx; - const uschar * errstr; - - uschar *dns_txt_name, *dns_txt_reply; - - /* Fetch public key for signing domain, from DNS */ - - dns_txt_name = string_sprintf("%s._domainkey.%s.", - sig->selector, sig->domain); - dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN); - memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN); - - if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK - || dns_txt_reply[0] == '\0') + /* Make sure we have all required signature tags */ + if (!( sig->domain && *sig->domain + && sig->selector && *sig->selector + && sig->headernames && *sig->headernames + && sig->bodyhash.data + && sig->sighash.data + && sig->algo > -1 + && sig->version + ) ) { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; - goto NEXT_VERIFY; - } + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR; - DEBUG(D_acl) - { - debug_printf( - "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" - " Raw record: "); - pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); + DEBUG(D_acl) debug_printf( + " Error in DKIM-Signature header: tags missing or invalid\n" + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + goto NEXT_VERIFY; } - if (!(sig->pubkey = pdkim_parse_pubkey_record(ctx, dns_txt_reply))) + /* Make sure sig uses supported DKIM version (only v1) */ + if (sig->version != 1) { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD; + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION; DEBUG(D_acl) debug_printf( - " Error while parsing public key record\n" - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + " Error in DKIM-Signature header: unsupported DKIM version\n" + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); goto NEXT_VERIFY; } - DEBUG(D_acl) debug_printf( - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err))) + goto NEXT_VERIFY; + + /* If the pubkey limits to a list of specific hashes, ignore sigs that + do not have the hash part of the sig algorithm matching */ - /* Import public key */ - if ((errstr = exim_rsa_verify_init(&sig->pubkey->key, &vctx))) + if (sig->pubkey->hashes) { - DEBUG(D_acl) debug_printf("verify_init: %s\n", errstr); - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; - goto NEXT_VERIFY; + const uschar * list = sig->pubkey->hashes, * ele; + int sep = ':'; + while ((ele = string_nextinlist(&list, &sep, NULL, 0))) + if (Ustrcmp(ele, pdkim_algos[sig->algo] + 4) == 0) break; + if (!ele) + { + DEBUG(D_acl) debug_printf("pubkey h=%s vs sig a=%s\n", + sig->pubkey->hashes, pdkim_algos[sig->algo]); + sig->verify_status = PDKIM_VERIFY_FAIL; + sig->verify_ext_status = PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH; + goto NEXT_VERIFY; + } } /* Check the signature */ - if ((errstr = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sigdata))) +/*XXX needs extension for non-RSA */ + if ((*err = exim_dkim_verify(&vctx, is_sha1, &hhash, &sig->sighash))) { - DEBUG(D_acl) debug_printf("headers verify: %s\n", errstr); + DEBUG(D_acl) debug_printf("headers verify: %s\n", *err); sig->verify_status = PDKIM_VERIFY_FAIL; sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; goto NEXT_VERIFY; } - /* We have a winner! (if bodydhash was correct earlier) */ + /* We have a winner! (if bodyhash was correct earlier) */ if (sig->verify_status == PDKIM_VERIFY_NONE) sig->verify_status = PDKIM_VERIFY_PASS; @@ -1564,15 +1673,15 @@ return PDKIM_OK; /* -------------------------------------------------------------------------- */ DLLEXPORT pdkim_ctx * -pdkim_init_verify(int(*dns_txt_callback)(char *, char *)) +pdkim_init_verify(int(*dns_txt_callback)(char *, char *), BOOL dot_stuffing) { pdkim_ctx * ctx; ctx = store_get(sizeof(pdkim_ctx)); memset(ctx, 0, sizeof(pdkim_ctx)); +if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); -ctx->mode = PDKIM_MODE_VERIFY; ctx->dns_txt_callback = dns_txt_callback; return ctx; @@ -1581,34 +1690,57 @@ return ctx; /* -------------------------------------------------------------------------- */ +/*XXX ? needs extension to cover non-RSA algo? Currently the "algo" is actually +the combo of algo and hash-method */ + DLLEXPORT pdkim_ctx * -pdkim_init_sign(char *domain, char *selector, char *rsa_privkey, int algo) +pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo, + BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *), + const uschar ** errstr) { -pdkim_ctx *ctx; -pdkim_signature *sig; +pdkim_ctx * ctx; +pdkim_signature * sig; if (!domain || !selector || !rsa_privkey) return NULL; -ctx = store_get(sizeof(pdkim_ctx)); +ctx = store_get(sizeof(pdkim_ctx) + PDKIM_MAX_BODY_LINE_LEN + sizeof(pdkim_signature)); memset(ctx, 0, sizeof(pdkim_ctx)); -ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); +ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; +ctx->linebuf = CS (ctx+1); -sig = store_get(sizeof(pdkim_signature)); +DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; + +sig = (pdkim_signature *)(ctx->linebuf + PDKIM_MAX_BODY_LINE_LEN); memset(sig, 0, sizeof(pdkim_signature)); sig->bodylength = -1; - -ctx->mode = PDKIM_MODE_SIGN; ctx->sig = sig; -sig->domain = string_copy(domain); -sig->selector = string_copy(selector); -sig->rsa_privkey = string_copy(rsa_privkey); +sig->domain = string_copy(US domain); +sig->selector = string_copy(US selector); +sig->rsa_privkey = string_copy(US rsa_privkey); sig->algo = algo; -exim_sha_init(&sig->body_hash, algo == PDKIM_ALGO_RSA_SHA1); +/*XXX extend for sha512 */ +if (!exim_sha_init(&sig->body_hash_ctx, + algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hash setup internal error\n"); + return NULL; + } + +DEBUG(D_acl) + { + pdkim_signature s = *sig; + ev_ctx vctx; + + debug_printf("PDKIM (checking verify key)>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + if (!pdkim_key_from_dns(ctx, &s, &vctx, errstr)) + debug_printf("WARNING: bad dkim key in dns\n"); + debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + } return ctx; } @@ -1628,7 +1760,7 @@ pdkim_set_optional(pdkim_ctx *ctx, pdkim_signature * sig = ctx->sig; if (identity) - sig->identity = string_copy(identity); + sig->identity = string_copy(US identity); sig->sign_headers = string_copy(sign_headers ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS); @@ -1646,7 +1778,7 @@ return PDKIM_OK; void pdkim_init(void) { -exim_rsa_init(); +exim_dkim_init(); }