X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/be24b950ae0db88b1c9811b3a028e95133c55efa..e3e281ccf9d8777d0df98ddd644720573e0343d1:/src/src/pdkim/pdkim.c diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c index f6d70bfc9..05f656df4 100644 --- a/src/src/pdkim/pdkim.c +++ b/src/src/pdkim/pdkim.c @@ -2,7 +2,8 @@ * PDKIM - a RFC4871 (DKIM) implementation * * Copyright (C) 2009 - 2016 Tom Kistner - * Copyright (C) 2016 - 2018 Jeremy Harris + * Copyright (C) 2016 - 2020 Jeremy Harris + * Copyright (c) The Exim Maintainers 2021 * * http://duncanthrax.net/pdkim/ * @@ -107,7 +108,7 @@ pdkim_combined_canon_entry pdkim_combined_canons[] = { }; -static blob lineending = {.data = US"\r\n", .len = 2}; +static const blob lineending = {.data = US"\r\n", .len = 2}; /* -------------------------------------------------------------------------- */ uschar * @@ -720,9 +721,11 @@ return NULL; If we have to relax the data for this sig, return our copy of it. */ static blob * -pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, blob * orig_data, blob * relaxed_data) +pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, const blob * orig_data, blob * relaxed_data) { -blob * canon_data = orig_data; +const blob * canon_data = orig_data; +size_t left; + /* Defaults to simple canon (no further treatment necessary) */ if (b->canon_method == PDKIM_CANON_RELAXED) @@ -767,16 +770,17 @@ if (b->canon_method == PDKIM_CANON_RELAXED) } /* Make sure we don't exceed the to-be-signed body length */ +left = canon_data->len; if ( b->bodylength >= 0 - && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength + && left > (unsigned long)b->bodylength - b->signed_body_bytes ) - canon_data->len = b->bodylength - b->signed_body_bytes; + left = (unsigned long)b->bodylength - b->signed_body_bytes; -if (canon_data->len > 0) +if (left > 0) { - exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, canon_data->len); - b->signed_body_bytes += canon_data->len; - DEBUG(D_acl) pdkim_quoteprint(canon_data->data, canon_data->len); + exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, left); + b->signed_body_bytes += left; + DEBUG(D_acl) pdkim_quoteprint(canon_data->data, left); } return relaxed_data; @@ -822,7 +826,7 @@ for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next) /* VERIFICATION --------------------------------------------------------- */ /* Be careful that the header sig included a bodyash */ - if ( sig->bodyhash.data + if (sig->bodyhash.data && sig->bodyhash.len == b->bh.len && memcmp(b->bh.data, sig->bodyhash.data, b->bh.len) == 0) { DEBUG(D_acl) debug_printf("DKIM [%s] Body hash compared OK\n", sig->domain); @@ -1003,7 +1007,7 @@ else last_sig->next = sig; } - if (--dkim_collect_input == 0) + if (dkim_collect_input && --dkim_collect_input == 0) { ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s); ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0'; @@ -1111,14 +1115,14 @@ return string_catn(str, US"\r\n\t", 3); /* * RFC 5322 specifies that header line length SHOULD be no more than 78 - * lets make it so! * pdkim_headcat * - * returns uschar * (not nul-terminated) + * Returns gstring (not nul-terminated) appending to one supplied * * col: this int holds and receives column number (octets since last '\n') * str: partial string to append to - * pad: padding, split line or space after before or after eg: ";" + * pad: padding, split line or space after before or after eg: ";". + * Only the initial charater is used. * intro: - must join to payload eg "h=", usually the tag name * payload: eg base64 data - long data can be split arbitrarily. * @@ -1127,7 +1131,7 @@ return string_catn(str, US"\r\n\t", 3); * pairs and inside long values. it also always spaces or breaks after the * "pad" * - * no guarantees are made for output given out-of range input. like tag + * No guarantees are made for output given out-of range input. like tag * names longer than 78, or bogus col. Input is assumed to be free of line breaks. */ @@ -1135,92 +1139,64 @@ static gstring * pdkim_headcat(int * col, gstring * str, const uschar * pad, const uschar * intro, const uschar * payload) { -size_t l; - -if (pad) - { - l = Ustrlen(pad); - if (*col + l > 78) - str = pdkim_hdr_cont(str, col); - str = string_catn(str, pad, l); - *col += l; - } - -l = (pad?1:0) + (intro?Ustrlen(intro):0); - -if (*col + l > 78) - { /*can't fit intro - start a new line to make room.*/ - str = pdkim_hdr_cont(str, col); - l = intro?Ustrlen(intro):0; - } - -l += payload ? Ustrlen(payload):0 ; +int len, chomp, padded = 0; -while (l>77) - { /* this fragment will not fit on a single line */ - if (pad) - { - str = string_catn(str, US" ", 1); - *col += 1; - pad = NULL; /* only want this once */ - l--; - } - - if (intro) - { - size_t sl = Ustrlen(intro); - - str = string_catn(str, intro, sl); - *col += sl; - l -= sl; - intro = NULL; /* only want this once */ - } +/* If we can fit at least the pad at the end of current line, do it now. +Otherwise, wrap if there is a pad. */ - if (payload) +if (pad) + if (*col + 1 <= 78) { - size_t sl = Ustrlen(payload); - size_t chomp = *col+sl < 77 ? sl : 78-*col; - - str = string_catn(str, payload, chomp); - *col += chomp; - payload += chomp; - l -= chomp-1; + str = string_catn(str, pad, 1); + (*col)++; + pad = NULL; + padded = 1; } + else + str = pdkim_hdr_cont(str, col); - /* the while precondition tells us it didn't fit. */ - str = pdkim_hdr_cont(str, col); - } +/* Special case: if the whole addition does not fit at the end of the current +line, but could fit on a new line, wrap to give it its full, dedicated line. */ -if (*col + l > 78) +len = (pad ? 2 : padded) + + (intro ? Ustrlen(intro) : 0) + + (payload ? Ustrlen(payload) : 0); +if (len <= 77 && *col+len > 78) { str = pdkim_hdr_cont(str, col); - pad = NULL; + padded = 0; } +/* Either we already dealt with the pad or we know there is room */ + if (pad) { + str = string_catn(str, pad, 1); str = string_catn(str, US" ", 1); - *col += 1; - pad = NULL; + *col += 2; } - -if (intro) +else if (padded && *col < 78) { - size_t sl = Ustrlen(intro); - - str = string_catn(str, intro, sl); - *col += sl; - l -= sl; - intro = NULL; + str = string_catn(str, US" ", 1); + (*col)++; } -if (payload) - { - size_t sl = Ustrlen(payload); +/* Call recursively with intro as payload: it gets the same, special treatment +(that is, not split if < 78). */ - str = string_catn(str, payload, sl); - *col += sl; - } +if (intro) + str = pdkim_headcat(col, str, NULL, NULL, intro); + +if (payload) + for (len = Ustrlen(payload); len; len -= chomp) + { + if (*col >= 78) + str = pdkim_hdr_cont(str, col); + chomp = *col+len > 78 ? 78 - *col : len; + str = string_catn(str, payload, chomp); + *col += chomp; + payload += chomp; + } return str; } @@ -1352,7 +1328,8 @@ check_bare_ed25519_pubkey(pdkim_pubkey * p) int excess = p->key.len - 32; if (excess > 0) { - DEBUG(D_acl) debug_printf("DKIM: unexpected pubkey len %lu\n", p->key.len); + DEBUG(D_acl) + debug_printf("DKIM: unexpected pubkey len %lu\n", (unsigned long) p->key.len); p->key.data += excess; p->key.len = 32; } } @@ -1949,6 +1926,7 @@ if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; /* The line-buffer is for message data, hence tainted */ ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, TRUE); ctx->dns_txt_callback = dns_txt_callback; +ctx->cur_header = string_get_tainted(36, TRUE); return ctx; }