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From aed125484a346b4893c1a169088c39fe7ced01f3 Mon Sep 17 00:00:00 2001
From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Thu, 23 Apr 2020 12:53:12 +0300
Subject: [PATCH 06/13] lib-mail: message-parser - Truncate excessively long
MIME boundaries
RFC 2046 requires that the boundaries are a maximum of 70 characters
(excluding the "--" prefix and suffix). We allow 80 characters for a bit of
extra safety. Anything longer than that is truncated and treated the same
as if it was just 80 characters.
---
src/lib-mail/message-parser.c | 7 ++-
src/lib-mail/test-message-parser.c | 95 ++++++++++++++++++++++++++++++++++++++
2 files changed, 100 insertions(+), 2 deletions(-)
Signed-off-by: Sana Kazi <Sana.Kazi@kpit.com>
CVE: CVE-2020-12100
Upstream-Status: Backport [http://archive.ubuntu.com/ubuntu/pool/main/d/dovecot/dovecot_2.2.33.2-1ubuntu4.7.debian.tar.xz]
Comment: No change in any hunk
diff --git a/src/lib-mail/message-parser.c b/src/lib-mail/message-parser.c
index 6c6a680b5..92f541b02 100644
--- a/src/lib-mail/message-parser.c
+++ b/src/lib-mail/message-parser.c
@@ -10,7 +10,8 @@
/* RFC-2046 requires boundaries are max. 70 chars + "--" prefix + "--" suffix.
We'll add a bit more just in case. */
-#define BOUNDARY_END_MAX_LEN (70 + 2 + 2 + 10)
+#define BOUNDARY_STRING_MAX_LEN (70 + 10)
+#define BOUNDARY_END_MAX_LEN (BOUNDARY_STRING_MAX_LEN + 2 + 2)
struct message_boundary {
struct message_boundary *next;
@@ -526,8 +527,10 @@ static void parse_content_type(struct message_parser_ctx *ctx,
rfc2231_parse(&parser, &results);
for (; *results != NULL; results += 2) {
if (strcasecmp(results[0], "boundary") == 0) {
+ /* truncate excessively long boundaries */
ctx->last_boundary =
- p_strdup(ctx->parser_pool, results[1]);
+ p_strndup(ctx->parser_pool, results[1],
+ BOUNDARY_STRING_MAX_LEN);
break;
}
}
diff --git a/src/lib-mail/test-message-parser.c b/src/lib-mail/test-message-parser.c
index 1f1aa1437..94aa3eb7c 100644
--- a/src/lib-mail/test-message-parser.c
+++ b/src/lib-mail/test-message-parser.c
@@ -642,6 +642,100 @@ static void test_message_parser_no_eoh(void)
test_end();
}
+static void test_message_parser_long_mime_boundary(void)
+{
+ /* Close the boundaries in wrong reverse order. But because all
+ boundaries are actually truncated to the same size (..890) it
+ works the same as if all of them were duplicate boundaries. */
+static const char input_msg[] =
+"Content-Type: multipart/mixed; boundary=\"1234567890123456789012345678901234567890123456789012345678901234567890123456789012\"\n"
+"\n"
+"--1234567890123456789012345678901234567890123456789012345678901234567890123456789012\n"
+"Content-Type: multipart/mixed; boundary=\"123456789012345678901234567890123456789012345678901234567890123456789012345678901\"\n"
+"\n"
+"--123456789012345678901234567890123456789012345678901234567890123456789012345678901\n"
+"Content-Type: multipart/mixed; boundary=\"12345678901234567890123456789012345678901234567890123456789012345678901234567890\"\n"
+"\n"
+"--12345678901234567890123456789012345678901234567890123456789012345678901234567890\n"
+"Content-Type: text/plain\n"
+"\n"
+"1\n"
+"--1234567890123456789012345678901234567890123456789012345678901234567890123456789012\n"
+"Content-Type: text/plain\n"
+"\n"
+"22\n"
+"--123456789012345678901234567890123456789012345678901234567890123456789012345678901\n"
+"Content-Type: text/plain\n"
+"\n"
+"333\n"
+"--12345678901234567890123456789012345678901234567890123456789012345678901234567890\n"
+"Content-Type: text/plain\n"
+"\n"
+"4444\n";
+ struct message_parser_ctx *parser;
+ struct istream *input;
+ struct message_part *parts, *part;
+ struct message_block block;
+ pool_t pool;
+ int ret;
+
+ test_begin("message parser long mime boundary");
+ pool = pool_alloconly_create("message parser", 10240);
+ input = test_istream_create(input_msg);
+
+ parser = message_parser_init(pool, input, 0, 0);
+ while ((ret = message_parser_parse_next_block(parser, &block)) > 0) ;
+ test_assert(ret < 0);
+ message_parser_deinit(&parser, &parts);
+
+ part = parts;
+ test_assert(part->children_count == 6);
+ test_assert(part->flags == (MESSAGE_PART_FLAG_MULTIPART | MESSAGE_PART_FLAG_IS_MIME));
+ test_assert(part->header_size.lines == 2);
+ test_assert(part->header_size.physical_size == 126);
+ test_assert(part->header_size.virtual_size == 126+2);
+ test_assert(part->body_size.lines == 22);
+ test_assert(part->body_size.physical_size == 871);
+ test_assert(part->body_size.virtual_size == 871+22);
+
+ part = parts->children;
+ test_assert(part->children_count == 5);
+ test_assert(part->flags == (MESSAGE_PART_FLAG_MULTIPART | MESSAGE_PART_FLAG_IS_MIME));
+ test_assert(part->header_size.lines == 2);
+ test_assert(part->header_size.physical_size == 125);
+ test_assert(part->header_size.virtual_size == 125+2);
+ test_assert(part->body_size.lines == 19);
+ test_assert(part->body_size.physical_size == 661);
+ test_assert(part->body_size.virtual_size == 661+19);
+
+ part = parts->children->children;
+ test_assert(part->children_count == 4);
+ test_assert(part->flags == (MESSAGE_PART_FLAG_MULTIPART | MESSAGE_PART_FLAG_IS_MIME));
+ test_assert(part->header_size.lines == 2);
+ test_assert(part->header_size.physical_size == 124);
+ test_assert(part->header_size.virtual_size == 124+2);
+ test_assert(part->body_size.lines == 16);
+ test_assert(part->body_size.physical_size == 453);
+ test_assert(part->body_size.virtual_size == 453+16);
+
+ part = parts->children->children->children;
+ for (unsigned int i = 1; i <= 3; i++, part = part->next) {
+ test_assert(part->children_count == 0);
+ test_assert(part->flags == (MESSAGE_PART_FLAG_TEXT | MESSAGE_PART_FLAG_IS_MIME));
+ test_assert(part->header_size.lines == 2);
+ test_assert(part->header_size.physical_size == 26);
+ test_assert(part->header_size.virtual_size == 26+2);
+ test_assert(part->body_size.lines == 0);
+ test_assert(part->body_size.physical_size == i);
+ test_assert(part->body_size.virtual_size == i);
+ }
+
+ test_parsed_parts(input, parts);
+ i_stream_unref(&input);
+ pool_unref(&pool);
+ test_end();
+}
+
int main(void)
{
static void (*test_functions[])(void) = {
@@ -654,6 +748,7 @@ int main(void)
test_message_parser_garbage_suffix_mime_boundary,
test_message_parser_continuing_mime_boundary,
test_message_parser_continuing_truncated_mime_boundary,
+ test_message_parser_long_mime_boundary,
test_message_parser_no_eoh,
NULL
};
--
2.11.0
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