diff --git a/AUTHORS b/AUTHORS
index 39b676e04..cbb4f02e9 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -15,6 +15,8 @@ Stas Khirman
 Ryan Norton
 Andrew Resch
 
+Thanks to (github user) nervoir for bug reports
+
 Building and maintainance of the autotools scripts:
 Michael Wojciechowski
 Peter Koeleman
diff --git a/ChangeLog b/ChangeLog
index bb23e9298..472d9f775 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -76,6 +76,9 @@
 	* resume data no longer has timestamps of files
 	* require C++11 to build libtorrent
 
+	* fix utf-8 encoding check in torrent parser
+	* fix infinite loop when parsing maliciously crafted torrents
+	* fix invalid read in parse_int in bdecoder
 	* fix issue with very long tracker- and web seed URLs
 	* don't attempt to create empty files on startup, if they already exist
 	* fix force-recheck issue (new files would not be picked up)
diff --git a/include/libtorrent/string_util.hpp b/include/libtorrent/string_util.hpp
index abd4e0073..7f44eb81d 100644
--- a/include/libtorrent/string_util.hpp
+++ b/include/libtorrent/string_util.hpp
@@ -119,6 +119,15 @@ namespace libtorrent {
 	TORRENT_EXTRA_EXPORT bool is_i2p_url(std::string const& url);
 
 #endif
+
+	// this can be used as the hash function in std::unordered_*
+	struct TORRENT_EXTRA_EXPORT string_hash_no_case
+	{ size_t operator()(std::string const& s) const; };
+
+	// these can be used as the comparison functions in std::map and std::set
+	struct TORRENT_EXTRA_EXPORT string_eq_no_case
+	{ bool operator()(std::string const& lhs, std::string const& rhs) const; };
+
 }
 
 #endif
diff --git a/src/ConvertUTF.cpp b/src/ConvertUTF.cpp
index 422e992ba..e5789a1f0 100644
--- a/src/ConvertUTF.cpp
+++ b/src/ConvertUTF.cpp
@@ -300,7 +300,7 @@ Boolean isLegalUTF8(const UTF8 *source, int length) {
 	/* Everything else falls through when "true"... */
 	case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
 	case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
-	case 2: if ((a = (*--srcptr)) > 0xBF) return false;
+	case 2: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
 
 	switch (*source) {
 		/* no fall-through in this inner switch */
diff --git a/src/bdecode.cpp b/src/bdecode.cpp
index e0f424f90..446306bc6 100644
--- a/src/bdecode.cpp
+++ b/src/bdecode.cpp
@@ -121,10 +121,12 @@ namespace {
 	} // anonymous namespace
 
 
-	// fills in 'val' with what the string between start and the
-	// first occurrence of the delimiter is interpreted as an int.
-	// return the pointer to the delimiter, or 0 if there is a
-	// parse error. val should be initialized to zero
+	// reads the string between start and end, or up to the first occurrance of
+	// 'delimiter', whichever comes first. This string is interpreted as an
+	// integer which is assigned to 'val'. If there's a non-delimiter and
+	// non-digit in the range, a parse error is reported in 'ec'. If the value
+	// cannot be represented by the variable 'val' and overflow error is reported
+	// by 'ec'.
 	char const* parse_int(char const* start, char const* end, char delimiter
 		, std::int64_t& val, bdecode_errors::error_code_enum& ec)
 	{
@@ -150,8 +152,6 @@ namespace {
 			val += digit;
 			++start;
 		}
-		if (*start != delimiter)
-			ec = bdecode_errors::expected_colon;
 		return start;
 	}
 
@@ -663,9 +663,11 @@ namespace {
 		bool negative = false;
 		if (*ptr == '-') negative = true;
 		bdecode_errors::error_code_enum ec = bdecode_errors::no_error;
-		parse_int(ptr + negative
+		char const* end = parse_int(ptr + negative
 			, ptr + size, 'e', val, ec);
 		if (ec) return 0;
+		TORRENT_UNUSED(end);
+		TORRENT_ASSERT(end < ptr + size);
 		if (negative) val = -val;
 		return val;
 	}
@@ -890,6 +892,8 @@ namespace {
 					start = parse_int(start, end, ':', len, e);
 					if (e)
 						TORRENT_FAIL_BDECODE(e);
+					if (start == end)
+						TORRENT_FAIL_BDECODE(bdecode_errors::expected_colon);
 
 					// remaining buffer size excluding ':'
 					ptrdiff_t const buff_size = end - start - 1;
diff --git a/src/lazy_bdecode.cpp b/src/lazy_bdecode.cpp
index 904a4e8b6..71a6e80d3 100644
--- a/src/lazy_bdecode.cpp
+++ b/src/lazy_bdecode.cpp
@@ -131,6 +131,8 @@ namespace {
 					start = parse_int(start, end, ':', len, e);
 					if (e)
 						TORRENT_FAIL_BDECODE(e);
+					if (start == end)
+						TORRENT_FAIL_BDECODE(bdecode_errors::expected_colon);
 
 					// remaining buffer size excluding ':'
 					const ptrdiff_t buff_size = end - start - 1;
@@ -203,6 +205,8 @@ namespace {
 					start = parse_int(start, end, ':', len, e);
 					if (e)
 						TORRENT_FAIL_BDECODE(e);
+					if (start == end)
+						TORRENT_FAIL_BDECODE(bdecode_errors::expected_colon);
 
 					// remaining buffer size excluding ':'
 					const ptrdiff_t buff_size = end - start - 1;
diff --git a/src/string_util.cpp b/src/string_util.cpp
index ce7e2bba2..41edc027b 100644
--- a/src/string_util.cpp
+++ b/src/string_util.cpp
@@ -401,4 +401,27 @@ namespace libtorrent {
 
 #endif
 
+	std::size_t string_hash_no_case::operator()(std::string const& s) const
+	{
+		std::size_t ret = 5381;
+		for (std::string::const_iterator i = s.begin(); i != s.end(); ++i)
+			ret = (ret * 33) ^ static_cast<std::size_t>(to_lower(*i));
+		return ret;
+	}
+
+	bool string_eq_no_case::operator()(std::string const& lhs, std::string const& rhs) const
+	{
+		if (lhs.size() != rhs.size()) return false;
+
+		std::string::const_iterator s1 = lhs.begin();
+		std::string::const_iterator s2 = rhs.begin();
+
+		while (s1 != lhs.end() && s2 != rhs.end())
+		{
+			if (to_lower(*s1) != to_lower(*s2)) return false;
+			++s1;
+			++s2;
+		}
+		return true;
+	}
 }
diff --git a/src/torrent.cpp b/src/torrent.cpp
index 0b700528a..b7ee5a04c 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -5897,6 +5897,7 @@ namespace libtorrent {
 
 		if (is_paused()) return;
 		if (m_ses.is_aborted()) return;
+		if (is_upload_only()) return;
 
 		// this web seed may have redirected all files to other URLs, leaving it
 		// having no file left, and there's no longer any point in connecting to
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index 2f7a72726..0508c06dc 100644
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -244,8 +244,7 @@ namespace libtorrent {
 				continue;
 			}
 
-			if (code_point < 0
-				|| !valid_path_character(code_point))
+			if (code_point < 0 || !valid_path_character(code_point))
 			{
 				// invalid utf8 sequence, replace with "_"
 				path += '_';
@@ -254,9 +253,14 @@ namespace libtorrent {
 				continue;
 			}
 
+			TORRENT_ASSERT(isLegalUTF8(reinterpret_cast<UTF8 const*>(element.data() + i), seq_len));
+
 			// validation passed, add it to the output string
 			for (std::size_t k = i; k < i + std::size_t(seq_len); ++k)
+			{
+				TORRENT_ASSERT(element[k] != 0);
 				path.push_back(element[k]);
+			}
 
 			if (code_point == '.') ++num_dots;
 
@@ -486,46 +490,6 @@ namespace {
 		return true;
 	}
 
-	struct string_hash_no_case
-	{
-		std::size_t operator()(std::string const& s) const
-		{
-			char const* s1 = s.c_str();
-			std::size_t ret = 5381;
-			int c;
-
-			for (;;)
-			{
-				c = *s1++;
-				if (c == 0)
-					break;
-				ret = (ret * 33) ^ std::size_t(to_lower(char(c)));
-			}
-
-			return ret;
-		}
-	};
-
-	struct string_eq_no_case
-	{
-		bool operator()(std::string const& lhs, std::string const& rhs) const
-		{
-			char c1, c2;
-			char const* s1 = lhs.c_str();
-			char const* s2 = rhs.c_str();
-
-			while (*s1 != 0 && *s2 != 0)
-			{
-				c1 = to_lower(*s1);
-				c2 = to_lower(*s2);
-				if (c1 != c2) return false;
-				++s1;
-				++s2;
-			}
-			return *s1 == *s2;
-		}
-	};
-
 	// root_dir is the name of the torrent, unless this is a single file
 	// torrent, in which case it's empty.
 	bool extract_files(bdecode_node const& list, file_storage& target
@@ -644,7 +608,7 @@ namespace {
 		{
 			// as long as this file already exists
 			// increase the counter
-			std::uint32_t h = m_files.file_path_hash(i, empty_str);
+			std::uint32_t const h = m_files.file_path_hash(i, empty_str);
 			if (!files.insert(h).second)
 			{
 				// This filename appears to already exist!
diff --git a/src/web_connection_base.cpp b/src/web_connection_base.cpp
index 96b7737a8..1b62de42e 100644
--- a/src/web_connection_base.cpp
+++ b/src/web_connection_base.cpp
@@ -62,6 +62,8 @@ namespace libtorrent {
 
 		TORRENT_ASSERT(is_outgoing());
 
+		TORRENT_ASSERT(!m_torrent.lock()->is_upload_only());
+
 		// we only want left-over bandwidth
 		// TODO: introduce a web-seed default class which has a low download priority
 
@@ -102,9 +104,10 @@ namespace libtorrent {
 		// which fails because the m_num_connecting count is not consistent until
 		// after we call peer_connection::start
 		m_upload_only = true;
-		disconnect_if_redundant();
-		if (is_disconnecting()) return;
 		peer_connection::start();
+		// disconnect_if_redundant must be called after start to keep
+		// m_num_connecting consistent
+		disconnect_if_redundant();
 	}
 
 	web_connection_base::~web_connection_base() = default;
diff --git a/test/test_bdecode.cpp b/test/test_bdecode.cpp
index 6484d93f6..1915f6271 100644
--- a/test/test_bdecode.cpp
+++ b/test/test_bdecode.cpp
@@ -857,8 +857,9 @@ TORRENT_TEST(parse_int)
 {
 	char b[] = "1234567890e";
 	std::int64_t val = 0;
-	bdecode_errors::error_code_enum ec;
+	bdecode_errors::error_code_enum ec = bdecode_errors::no_error;
 	char const* e = parse_int(b, b + sizeof(b)-1, 'e', val, ec);
+	TEST_EQUAL(ec, bdecode_errors::no_error);
 	TEST_EQUAL(val, 1234567890);
 	TEST_EQUAL(e, b + sizeof(b) - 2);
 }
@@ -901,7 +902,7 @@ TORRENT_TEST(parse_length_overflow)
 		bdecode_node e;
 		int ret = bdecode(b[i], b[i] + strlen(b[i]), e, ec);
 		TEST_EQUAL(ret, -1);
-		TEST_CHECK(ec == error_code(bdecode_errors::unexpected_eof));
+		TEST_EQUAL(ec, error_code(bdecode_errors::unexpected_eof));
 	}
 }
 
@@ -910,9 +911,9 @@ TORRENT_TEST(expected_colon_string)
 {
 	char b[] = "928";
 	std::int64_t val = 0;
-	bdecode_errors::error_code_enum ec;
+	bdecode_errors::error_code_enum ec = bdecode_errors::no_error;
 	char const* e = parse_int(b, b + sizeof(b)-1, ':', val, ec);
-	TEST_EQUAL(ec, bdecode_errors::expected_colon);
+	TEST_EQUAL(ec, bdecode_errors::no_error);
 	TEST_EQUAL(e, b + 3);
 }
 
@@ -1395,6 +1396,21 @@ TORRENT_TEST(partial_parse4)
 	TEST_EQUAL(print_entry(e), "{ 'a': 1, 'b': 'foo', 'c': [ 1 ] }");
 }
 
+TORRENT_TEST(partial_parse_string)
+{
+	// it's important to not have a null terminator here
+	// to allow address sanitizer to trigger in case the decoder reads past the
+	// end
+	char b[] = { '5', '5'};
+
+	bdecode_node e;
+	error_code ec;
+	int pos;
+	int ret = bdecode(b, b + sizeof(b), e, ec, &pos);
+	TEST_EQUAL(ret, -1);
+	TEST_EQUAL(pos, 2);
+}
+
 // test switch_underlying_buffer
 TORRENT_TEST(switch_buffer)
 {
diff --git a/test/test_bencoding.cpp b/test/test_bencoding.cpp
index 1ef5edf13..ea26b8a4c 100644
--- a/test/test_bencoding.cpp
+++ b/test/test_bencoding.cpp
@@ -579,8 +579,9 @@ TORRENT_TEST(lazy_entry)
 	{
 		char b[] = "1234567890e";
 		std::int64_t val = 0;
-		bdecode_errors::error_code_enum ec;
+		bdecode_errors::error_code_enum ec = bdecode_errors::no_error;
 		char const* e = parse_int(b, b + sizeof(b)-1, 'e', val, ec);
+		TEST_CHECK(ec == bdecode_errors::no_error);
 		TEST_EQUAL(val, 1234567890);
 		TEST_EQUAL(e, b + sizeof(b) - 2);
 	}
@@ -607,9 +608,9 @@ TORRENT_TEST(lazy_entry)
 	{
 		char b[] = "928";
 		std::int64_t val = 0;
-		bdecode_errors::error_code_enum ec;
+		bdecode_errors::error_code_enum ec = bdecode_errors::no_error;
 		char const* e = parse_int(b, b + sizeof(b)-1, ':', val, ec);
-		TEST_CHECK(ec == bdecode_errors::expected_colon);
+		TEST_CHECK(ec == bdecode_errors::no_error);
 		TEST_EQUAL(e, b + 3);
 	}
 
diff --git a/test/test_string.cpp b/test/test_string.cpp
index ae8f10704..60e5bd031 100644
--- a/test/test_string.cpp
+++ b/test/test_string.cpp
@@ -412,3 +412,39 @@ TORRENT_TEST(i2p_url)
 	TEST_CHECK(!is_i2p_url("http://i2p/foo bar"));
 }
 #endif
+
+TORRENT_TEST(string_hash_no_case)
+{
+	string_hash_no_case hsh;
+
+	// make sure different strings yield different hashes
+	TEST_CHECK(hsh("ab") != hsh("ba"));
+
+	// make sure case is ignored
+	TEST_EQUAL(hsh("Ab"), hsh("ab"));
+	TEST_EQUAL(hsh("Ab"), hsh("aB"));
+
+	// make sure zeroes in strings are supported
+	TEST_CHECK(hsh(std::string("\0a", 2)) != hsh(std::string("\0b", 2)));
+	TEST_EQUAL(hsh(std::string("\0a", 2)), hsh(std::string("\0a", 2)));
+}
+
+TORRENT_TEST(string_eq_no_case)
+{
+	string_eq_no_case cmp;
+	TEST_CHECK(cmp("ab", "ba") == false);
+	TEST_CHECK(cmp("", ""));
+	TEST_CHECK(cmp("abc", "abc"));
+
+	// make sure different lengths are correctly treated as different
+	TEST_CHECK(cmp("abc", "ab") == false);
+
+	// make sure case is ignored
+	TEST_CHECK(cmp("Ab", "ab"));
+	TEST_CHECK(cmp("Ab", "aB"));
+
+	// make sure zeros are supported
+	TEST_CHECK(cmp(std::string("\0a", 2), std::string("\0b", 2)) == false);
+	TEST_CHECK(cmp(std::string("\0a", 2), std::string("\0a", 2)));
+}
+
diff --git a/test/test_torrent_info.cpp b/test/test_torrent_info.cpp
index 930b58258..bbe89dddf 100644
--- a/test/test_torrent_info.cpp
+++ b/test/test_torrent_info.cpp
@@ -350,6 +350,10 @@ TORRENT_TEST(sanitize_path_trailing_spaces)
 TORRENT_TEST(sanitize_path)
 {
 	std::string path;
+	sanitize_append_path_element(path, "\0\0\xed\0\x80");
+	TEST_EQUAL(path, "_");
+
+	path.clear();
 	sanitize_append_path_element(path, "/a/");
 	sanitize_append_path_element(path, "b");
 	sanitize_append_path_element(path, "c");
@@ -530,6 +534,17 @@ TORRENT_TEST(sanitize_path)
 	TEST_EQUAL(path, "foobar");
 }
 
+TORRENT_TEST(sanitize_path_zeroes)
+{
+	std::string path;
+	sanitize_append_path_element(path, "\0foo");
+	TEST_EQUAL(path, "_");
+
+	path.clear();
+	sanitize_append_path_element(path, "\0\0\0\0");
+	TEST_EQUAL(path, "_");
+}
+
 TORRENT_TEST(verify_encoding)
 {
 	// verify_encoding
@@ -609,6 +624,12 @@ TORRENT_TEST(verify_encoding)
 	TEST_CHECK(!verify_encoding(test));
 	std::printf("%s\n", test.c_str());
 	TEST_CHECK(test == "filename____");
+
+	// missing byte header
+	test = "filename\xed\0\x80";
+	TEST_CHECK(!verify_encoding(test));
+	fprintf(stdout, "%s\n", test.c_str());
+	TEST_CHECK(test == "filename_");
 }
 
 TORRENT_TEST(parse_torrents)