From: Tomek Mrugalski <tomasz@isc.org>
Date: Thu, 19 May 2016 13:54:23 +0000 (+0200)
Subject: [4510] Fix for escaped characters (e.g. backslashes) in option contents.
X-Git-Tag: trac4106_update_base~7^2~1^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=22f72b302e4f3e86f8c52ab6e108718abfdf4282;p=thirdparty%2Fkea.git

[4510] Fix for escaped characters (e.g. backslashes) in option contents.
---

diff --git a/src/lib/cc/tests/data_unittests.cc b/src/lib/cc/tests/data_unittests.cc
index a8001a29be..f5643dbb00 100644
--- a/src/lib/cc/tests/data_unittests.cc
+++ b/src/lib/cc/tests/data_unittests.cc
@@ -561,15 +561,26 @@ TEST(Element, escape) {
     EXPECT_NO_THROW(Element::fromJSON("\"  \n  \r \t \f  \n \n    \t\""));
 }
 
-// This test verifies if a backslash can be defined properly.
-TEST(Element, backslash) {
-    string input = "SMSBoot\\\\x64"; // Two slashes put in the config file...
-    string exp = "SMSBoot\\x64"; // ... should result in one slash in the actual option.
+// This test verifies that a backslash can be used in element content
+// when the element is created using constructor.
+TEST(Element, backslash1) {
+    string input = "SMSBoot\\x64";// One slash passed to elem constructor...
+    string exp = "SMSBoot\\x64";  // ... should result in one slash in the actual option.
 
     StringElement elem(input);
     EXPECT_EQ(exp, elem.stringValue());
 }
 
+// This test verifies that a backslash can be used in element content
+// when the element is created using fromJSON.
+TEST(Element, backslash2) {
+    string input = "\"SMSBoot\\\\x64\""; // Two slashes put in the config file...
+    string exp = "SMSBoot\\x64"; // ... should result in one slash in the actual option.
+
+    ElementPtr elem = Element::fromJSON(input);
+    EXPECT_EQ(exp, elem->stringValue());
+}
+
 TEST(Element, ListElement) {
     // this function checks the specific functions for ListElements
     ElementPtr el = Element::fromJSON("[ 1, \"bar\", 3 ]");
diff --git a/src/lib/dhcpsrv/parsers/dhcp_parsers.cc b/src/lib/dhcpsrv/parsers/dhcp_parsers.cc
index 0cabcbe9c9..10222af49b 100644
--- a/src/lib/dhcpsrv/parsers/dhcp_parsers.cc
+++ b/src/lib/dhcpsrv/parsers/dhcp_parsers.cc
@@ -164,7 +164,14 @@ template <> void ValueParser<std::string>::build(ConstElementPtr value) {
     // Invoke common code for all specializations of build().
     buildCommon(value);
 
-    value_ = value->str();
+    // For strings we need to use stringValue() rather than str().
+    // str() returns fully escaped special characters, so
+    // single backslash would be misrepresented as "\\".
+    if (value->getType() == Element::string) {
+        value_ = value->stringValue();
+    } else {
+        value_ = value->str();
+    }
     boost::erase_all(value_, "\"");
 }
 
diff --git a/src/lib/dhcpsrv/tests/dhcp_parsers_unittest.cc b/src/lib/dhcpsrv/tests/dhcp_parsers_unittest.cc
index 99e8177f89..673707968a 100644
--- a/src/lib/dhcpsrv/tests/dhcp_parsers_unittest.cc
+++ b/src/lib/dhcpsrv/tests/dhcp_parsers_unittest.cc
@@ -655,6 +655,50 @@ TEST_F(ParseConfigTest, minimalOptionDataTest) {
     EXPECT_EQ(val, opt_ptr->toText());
 }
 
+/// @brief Check parsing of options with escape characters.
+///
+/// Note that this tests basic operation of the OptionDataListParser and
+/// OptionDataParser.  It uses a simple configuration consisting of one
+/// one definition and matching option data.  It verifies that the option
+/// is parsed and committed to storage correctly and that its content
+/// has the actual character (e.g. an actual backslash, not double backslash).
+TEST_F(ParseConfigTest, escapedOptionDataTest) {
+
+    parser_context_->universe_ = Option::V4;
+
+    // We need to use double escapes here. The first backslash will
+    // be consumed by C++ preprocessor, so the actual string will
+    // have two backslash characters: \\SMSBoot\\x64\\wdsnbp.com.
+    //
+    std::string config =
+        "{\"option-data\": [ {"
+        "    \"name\": \"boot-file-name\","
+        "    \"data\": \"\\\\SMSBoot\\\\x64\\\\wdsnbp.com\""
+        " } ]"
+        "}";
+    std::cout << config << std::endl;
+
+    // Verify that the configuration string parses.
+    int rcode = parseConfiguration(config);
+    ASSERT_EQ(0, rcode);
+
+    // Verify that the option can be retrieved.
+    OptionPtr opt = getOptionPtr("dhcp4", DHO_BOOT_FILE_NAME);
+    ASSERT_TRUE(opt);
+
+    util::OutputBuffer buf(100);
+
+    uint8_t exp[] = { DHO_BOOT_FILE_NAME, 23, '\\', 'S', 'M', 'S', 'B', 'o', 'o',
+                      't', '\\', 'x', '6', '4', '\\', 'w', 'd', 's', 'n', 'b',
+                      'p', '.', 'c', 'o', 'm' };
+    ASSERT_EQ(25, sizeof(exp));
+
+    opt->pack(buf);
+    EXPECT_EQ(Option::OPTION4_HDR_LEN + 23, buf.getLength());
+
+    EXPECT_TRUE(0 == memcmp(buf.getData(), exp, 25));
+}
+
 // This test checks behavior of the configuration parser for option data
 // for different values of csv-format parameter and when there is an option
 // definition present.