Blame SOURCES/dovecot-2.3.13-CVE_2020_25275-part7.patch

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From fb97a1cddbda4019e327fa736972a1c7433fedaa Mon Sep 17 00:00:00 2001
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From: Timo Sirainen <timo.sirainen@open-xchange.com>
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Date: Fri, 11 Sep 2020 09:53:03 +0300
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Subject: [PATCH] lib-mail: message-parser - Fix assert-crash when enforcing
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 MIME part limit
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The limit could have been exceeded with message/rfc822 parts.
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---
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 src/lib-mail/message-parser.c      |  3 +-
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 src/lib-mail/test-message-parser.c | 82 ++++++++++++++++++++++++++++++
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 2 files changed, 84 insertions(+), 1 deletion(-)
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diff --git a/src/lib-mail/message-parser.c b/src/lib-mail/message-parser.c
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index 6ab4c3266f..40a504da0a 100644
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--- a/src/lib-mail/message-parser.c
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+++ b/src/lib-mail/message-parser.c
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@@ -703,7 +703,8 @@ static int parse_next_header(struct message_parser_ctx *ctx,
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 		ctx->multipart = FALSE;
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 		ctx->parse_next_block = parse_next_body_to_boundary;
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 	} else if ((part->flags & MESSAGE_PART_FLAG_MESSAGE_RFC822) != 0 &&
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-		   !parse_too_many_nested_mime_parts(ctx)) {
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+		   !parse_too_many_nested_mime_parts(ctx) &&
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+		   ctx->total_parts_count < ctx->max_total_mime_parts) {
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 		ctx->parse_next_block = parse_next_body_message_rfc822_init;
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 	} else {
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 		part->flags &= ~MESSAGE_PART_FLAG_MESSAGE_RFC822;
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diff --git a/src/lib-mail/test-message-parser.c b/src/lib-mail/test-message-parser.c
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index 8c5a3404f1..c4e117afc7 100644
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--- a/src/lib-mail/test-message-parser.c
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+++ b/src/lib-mail/test-message-parser.c
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@@ -1127,6 +1127,87 @@ static const char input_msg[] =
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 	test_end();
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 }
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+static void test_message_parser_mime_part_limit_rfc822(void)
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+{
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+static const char input_msg[] =
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+"Content-Type: multipart/mixed; boundary=\"1\"\n"
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+"\n"
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+"--1\n"
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+"Content-Type: multipart/mixed; boundary=\"2\"\n"
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+"\n"
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+"--2\n"
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+"Content-Type: message/rfc822\n"
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+"\n"
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+"Content-Type: text/plain\n"
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+"\n"
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+"1\n"
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+"--2\n"
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+"Content-Type: message/rfc822\n"
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+"\n"
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+"Content-Type: text/plain\n"
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+"\n"
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+"22\n"
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+"--1\n"
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+"Content-Type: message/rfc822\n"
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+"\n"
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+"Content-Type: text/plain\n"
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+"\n"
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+"333\n";
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+	const struct message_parser_settings parser_set = {
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+		.max_total_mime_parts = 3,
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+	};
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+	struct message_parser_ctx *parser;
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+	struct istream *input;
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+	struct message_part *parts, *part;
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+	struct message_block block;
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+	pool_t pool;
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+	int ret;
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+
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+	test_begin("message parser mime part limit rfc822");
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+	pool = pool_alloconly_create("message parser", 10240);
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+	input = test_istream_create(input_msg);
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+
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+	parser = message_parser_init(pool, input, &parser_set);
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+	while ((ret = message_parser_parse_next_block(parser, &block)) > 0) ;
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+	test_assert(ret < 0);
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+	message_parser_deinit(&parser, &parts;;
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+
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+	part = parts;
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+	test_assert(part->children_count == 2);
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+	test_assert(part->flags == (MESSAGE_PART_FLAG_MULTIPART | MESSAGE_PART_FLAG_IS_MIME));
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+	test_assert(part->header_size.lines == 2);
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+	test_assert(part->header_size.physical_size == 45);
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+	test_assert(part->header_size.virtual_size == 45+2);
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+	test_assert(part->body_size.lines == 21);
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+	test_assert(part->body_size.physical_size == 238);
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+	test_assert(part->body_size.virtual_size == 238+21);
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+
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+	part = parts->children;
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+	test_assert(part->children_count == 1);
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+	test_assert(part->flags == (MESSAGE_PART_FLAG_MULTIPART | MESSAGE_PART_FLAG_IS_MIME));
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+	test_assert(part->header_size.lines == 2);
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+	test_assert(part->header_size.physical_size == 45);
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+	test_assert(part->header_size.virtual_size == 45+2);
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+	test_assert(part->body_size.lines == 18);
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+	test_assert(part->body_size.physical_size == 189);
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+	test_assert(part->body_size.virtual_size == 189+18);
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+
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+	part = parts->children->children;
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+	test_assert(part->children_count == 0);
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+	test_assert(part->flags == MESSAGE_PART_FLAG_IS_MIME);
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+	test_assert(part->header_size.lines == 2);
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+	test_assert(part->header_size.physical_size == 30);
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+	test_assert(part->header_size.virtual_size == 30+2);
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+	test_assert(part->body_size.lines == 15);
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+	test_assert(part->body_size.physical_size == 155);
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+	test_assert(part->body_size.virtual_size == 155+15);
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+
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+	test_parsed_parts(input, parts);
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+	i_stream_unref(&input);
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+	pool_unref(&pool);
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+	test_end();
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+}
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+
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 int main(void)
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 {
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 	static void (*const test_functions[])(void) = {
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@@ -1301,6 +1382,7 @@ int main(void)
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 		test_message_parser_mime_part_nested_limit,
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 		test_message_parser_mime_part_nested_limit_rfc822,
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 		test_message_parser_mime_part_limit,
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+		test_message_parser_mime_part_limit_rfc822,
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 		NULL
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 	};
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 	return test_run(test_functions);