From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Fri, 4 May 2018 16:49:57 +0000 (+0300)
Subject: lib-mail: Add MESSAGE_ADDRESS_PARSE_FLAG_NON_STRICT_DOTS
X-Git-Tag: 2.3.9~1612
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0d9218abe8f20ea8e2b72c2217e1ff51265b7541;p=thirdparty%2Fdovecot%2Fcore.git

lib-mail: Add MESSAGE_ADDRESS_PARSE_FLAG_NON_STRICT_DOTS

This code is somewhat copy&pasted from parse_local_part() in Pigeonhole.
---

diff --git a/src/lib-mail/message-address.c b/src/lib-mail/message-address.c
index 4880a545ae..fcd525e309 100644
--- a/src/lib-mail/message-address.c
+++ b/src/lib-mail/message-address.c
@@ -15,7 +15,7 @@ struct message_address_parser_context {
 	struct message_address *first_addr, *last_addr, addr;
 	string_t *str;
 
-	bool fill_missing;
+	bool fill_missing, non_strict_dots;
 };
 
 static void add_address(struct message_address_parser_context *ctx)
@@ -77,6 +77,29 @@ static void str_append_maybe_escape(string_t *dest, const char *cstr, bool escap
 	str_append_c(dest, '"');
 }
 
+static int
+parse_nonstrict_dot_atom(struct rfc822_parser_context *ctx, string_t *str)
+{
+	int ret = -1;
+
+	do {
+		while (*ctx->data == '.') {
+			str_append_c(str, '.');
+			ctx->data++;
+			if (ctx->data == ctx->end) {
+				/* @domain is missing, but local-part
+				   parsing was successful */
+				return 0;
+			}
+			ret = 1;
+		}
+		if (*ctx->data == '@')
+			break;
+		ret = rfc822_parse_atom(ctx, str);
+	} while (ret > 0 && *ctx->data == '.');
+	return ret;
+}
+
 static int parse_local_part(struct message_address_parser_context *ctx)
 {
 	int ret;
@@ -90,8 +113,10 @@ static int parse_local_part(struct message_address_parser_context *ctx)
 	str_truncate(ctx->str, 0);
 	if (*ctx->parser.data == '"')
 		ret = rfc822_parse_quoted_string(&ctx->parser, ctx->str);
-	else
+	else if (!ctx->non_strict_dots)
 		ret = rfc822_parse_dot_atom(&ctx->parser, ctx->str);
+	else
+		ret = parse_nonstrict_dot_atom(&ctx->parser, ctx->str);
 	if (ret < 0)
 		return -1;
 
@@ -431,6 +456,7 @@ message_address_parse_real(pool_t pool, const unsigned char *data, size_t size,
 	ctx.pool = pool;
 	ctx.str = t_str_new(128);
 	ctx.fill_missing = (flags & MESSAGE_ADDRESS_PARSE_FLAG_FILL_MISSING) != 0;
+	ctx.non_strict_dots = (flags & MESSAGE_ADDRESS_PARSE_FLAG_NON_STRICT_DOTS) != 0;
 
 	if (rfc822_skip_lwsp(&ctx.parser) <= 0) {
 		/* no addresses */
diff --git a/src/lib-mail/message-address.h b/src/lib-mail/message-address.h
index 3498df0ffe..ec9b10f2f4 100644
--- a/src/lib-mail/message-address.h
+++ b/src/lib-mail/message-address.h
@@ -7,6 +7,11 @@ enum message_address_parse_flags {
 	/* If enabled, missing mailbox and domain are set to MISSING_MAILBOX
 	   and MISSING_DOMAIN strings. Otherwise they're set to "". */
 	MESSAGE_ADDRESS_PARSE_FLAG_FILL_MISSING = BIT(0),
+	/* Allow local-part to contain any number of dots anywhere in it.
+	   For example ".user", "us..ser" and "user." will be valid. This
+	   isn't strictly allowed by RFC5322, but these addresses are commonly
+	   used in Japan. */
+	MESSAGE_ADDRESS_PARSE_FLAG_NON_STRICT_DOTS = BIT(1),
 };
 
 /* group: ... ; will be stored like:
diff --git a/src/lib-mail/test-message-address.c b/src/lib-mail/test-message-address.c
index 41cad7945d..d46d2fc14b 100644
--- a/src/lib-mail/test-message-address.c
+++ b/src/lib-mail/test-message-address.c
@@ -339,6 +339,40 @@ static void test_message_address_nuls(void)
 	test_end();
 }
 
+static void test_message_address_non_strict_dots(void)
+{
+	const char *const inputs[] = {
+		".@example.com",
+		"..@example.com",
+		"..foo@example.com",
+		"..foo..@example.com",
+		"..foo..bar..@example.com",
+	};
+	const struct message_address *addr;
+	struct message_address output = {
+		NULL, NULL, NULL, "local-part",
+		"example.com", FALSE
+	};
+
+	test_begin("message address parsing with non-strict dots");
+	for (unsigned int i = 0; i < N_ELEMENTS(inputs); i++) {
+		const unsigned char *addr_input =
+			(const unsigned char *)inputs[i];
+		/* invalid without non-strict-dots flag */
+		addr = message_address_parse(pool_datastack_create(),
+			addr_input, strlen(inputs[i]), UINT_MAX, 0);
+		test_assert_idx(addr != NULL && addr->invalid_syntax, i);
+
+		/* valid with the non-strict-dots flag */
+		addr = message_address_parse(pool_datastack_create(),
+			addr_input, strlen(inputs[i]), UINT_MAX,
+			MESSAGE_ADDRESS_PARSE_FLAG_NON_STRICT_DOTS);
+		output.mailbox = t_strcut(inputs[i], '@');
+		test_assert_idx(addr != NULL && cmp_addr(addr, &output), i);
+	}
+	test_end();
+}
+
 static int
 test_parse_path(const char *input, const struct message_address **addr_r)
 {
@@ -464,6 +498,7 @@ int main(void)
 	static void (*const test_functions[])(void) = {
 		test_message_address,
 		test_message_address_nuls,
+		test_message_address_non_strict_dots,
 		test_message_address_path,
 		test_message_address_path_invalid,
 		NULL