added util::attr_escape

escaping string for inclusion into x(ht)ml attributes

Signed-off-by: Michael Krelin <hacker@klever.net>

2 files changed, 26 insertions, 0 deletions

diff --git a/include/opkele/util.h b/include/opkele/util.h
index 6f3ddf6..719f951 100644
--- a/include/opkele/util.h
+++ b/include/opkele/util.h
@@ -55,96 +55,103 @@ namespace opkele {
 		const DH* operator->() const { return _dh; }
 	};
 
 	/**
 	 * Convert base64-encoded SSL BIGNUM to internal representation.
 	 * @param b64 base64-encoded number
 	 * @return SSL BIGNUM
 	 * @throw failed_conversion in case of error
 	 */
 	BIGNUM *base64_to_bignum(const string& b64);
 	/**
 	 * Convert decimal representation to SSL BIGNUM.
 	 * @param dec decimal representation
 	 * @return resulting BIGNUM
 	 * @throw failed_conversion in case of error
 	 */
 	BIGNUM *dec_to_bignum(const string& dec);
 	/**
 	 * Convert SSL BIGNUM data to base64 encoded string.
 	 * @param bn BIGNUM
 	 * @return base64encoded string
 	 */
 	string bignum_to_base64(const BIGNUM *bn);
 
 	/**
 	 * Convert internal time representation to w3c format
 	 * @param t internal representation
 	 * @return w3c time
 	 * @throw failed_conversion in case of error
 	 */
 	string time_to_w3c(time_t t);
 	/**
 	 * Convert W3C time representation to  internal time_t
 	 * @param w w3c representation
 	 * @return converted time
 	 * @throw failed_conversion in case of error
 	 */
 	time_t w3c_to_time(const string& w);
 
 	/**
 	 * Encode string to the representation suitable for using in URL.
 	 * @param str string to encode
 	 * @return encoded string
 	 * @throw failed_conversion in case of failure
 	 */
 	string url_encode(const string& str);
 
 	/**
+	 * Make string suitable for using as x(ht)ml attribute.
+	 * @param str string to escape
+	 * @return escaped string
+	 */
+	string attr_escape(const string& str);
+
+	/**
 	 * Convert number to string
 	 * @param l number
 	 * @return string representation
 	 * @throw failed_conversion in case of failure
 	 */
 	string long_to_string(long l);
 	/**
 	 * Convert string to number
 	 * @param s string, containing the number
 	 * @return the number
 	 * @throw failed_conversion in case of failure
 	 */
 	long string_to_long(const string& s);
 
 	/**
 	 * Encode binary data using base64.
 	 * @param data pointer to binary data
 	 * @param length length of data
 	 * @return encoded data
 	 */
 	string encode_base64(const void *data,size_t length);
 	/**
 	 * Decode binary data from base64 representation.
 	 * @param data base64-encoded data
 	 * @param rv container for decoded binary
 	 */
 	void decode_base64(const string& data,vector<unsigned char>& rv);
 
 	/**
 	 * Normalize http(s) URI according to RFC3986, section 6. URI is
 	 * expected to have scheme: in front of it.
 	 * @param uri URI
 	 * @return normalized URI
 	 * @throw not_implemented in case of non-httpi(s) URI
 	 * @throw bad_input in case of malformed URI
 	 */
 	string rfc_3986_normalize_uri(const string& uri);
 
 	string& strip_uri_fragment_part(string& uri);
 
 	string abi_demangle(const char* mn);
 
 	string base64_signature(const assoc_t& assoc,const basic_openid_message& om);
 
 	class change_mode_message_proxy : public basic_openid_message {
 	    public:
 		const basic_openid_message& x;
 		const string& mode;
diff --git a/lib/util.cc b/lib/util.cc
index 54d6535..b7bc437 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -116,96 +116,115 @@ namespace opkele {
 	    char rv[25];
 	    if(!strftime(rv,sizeof(rv)-1,"%Y-%m-%dT%H:%M:%SZ",&tm_t))
 		throw failed_conversion(OPKELE_CP_ "failed to strftime()");
 	    return rv;
 	}
 
 	time_t w3c_to_time(const string& w) {
 	    int fraction;
 	    struct tm tm_t;
 	    memset(&tm_t,0,sizeof(tm_t));
 	    if( (
 			sscanf(
 			    w.c_str(),
 			    "%04d-%02d-%02dT%02d:%02d:%02dZ",
 			    &tm_t.tm_year,&tm_t.tm_mon,&tm_t.tm_mday,
 			    &tm_t.tm_hour,&tm_t.tm_min,&tm_t.tm_sec
 			    ) != 6
 		) && (
 		    sscanf(
 			w.c_str(),
 			"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ",
 			&tm_t.tm_year,&tm_t.tm_mon,&tm_t.tm_mday,
 			&tm_t.tm_hour,&tm_t.tm_min,&tm_t.tm_sec,
 			&fraction
 			) != 7
 		    ) )
 		throw failed_conversion(OPKELE_CP_ "failed to sscanf()");
 	    tm_t.tm_mon--;
 	    tm_t.tm_year-=1900;
 	    time_t rv = mktime(&tm_t);
 	    if(rv==(time_t)-1)
 		throw failed_conversion(OPKELE_CP_ "failed to mktime()");
 	    return rv-timezone;
 	}
 
 	/*
 	 *
 	 */
 
 	string url_encode(const string& str) {
 	    char * t = curl_escape(str.c_str(),str.length());
 	    if(!t)
 		throw failed_conversion(OPKELE_CP_ "failed to curl_escape()");
 	    string rv(t);
 	    curl_free(t);
 	    return rv;
 	}
 
+	string attr_escape(const string& str) {
+	    static const char *unsafechars = "<>&\n\"'";
+	    string rv;
+	    string::size_type p=0;
+	    while(true) {
+		string::size_type us = str.find_first_of(unsafechars,p);
+		if(us==string::npos) {
+		    if(p!=str.length())
+			rv.append(str,p,str.length()-p);
+		    return rv;
+		}
+		rv.append(str,p,us-p);
+		rv += "&#";
+		rv += long_to_string((long)str[us]);
+		rv += ';';
+		p = us+1;
+	    }
+	}
+
 	string long_to_string(long l) {
 	    char rv[32];
 	    int r=snprintf(rv,sizeof(rv),"%ld",l);
 	    if(r<0 || r>=(int)sizeof(rv))
 		throw failed_conversion(OPKELE_CP_ "failed to snprintf()");
 	    return rv;
 	}
 
 	long string_to_long(const string& s) {
 	    char *endptr = 0;
 	    long rv = strtol(s.c_str(),&endptr,10);
 	    if((!endptr) || endptr==s.c_str())
 		throw failed_conversion(OPKELE_CP_ "failed to strtol()");
 	    return rv;
 	}
 
 	/*
 	 * Normalize URL according to the rules, described in rfc 3986, section 6
 	 *
 	 * - uppercase hex triplets (e.g. %ab -> %AB)
 	 * - lowercase scheme and host
 	 * - decode %-encoded characters, specified as unreserved in rfc 3986, section 2.3,
 	 *   that is - [:alpha:][:digit:]._~-
 	 * - remove dot segments
 	 * - remove empty and default ports
 	 * - if there's no path component, add '/'
 	 */
 	 string rfc_3986_normalize_uri(const string& uri) {
 	     static const char *whitespace = " \t\r\n";
 	     string rv;
 	     string::size_type ns = uri.find_first_not_of(whitespace);
 	     if(ns==string::npos)
 		 throw bad_input(OPKELE_CP_ "Can't normalize empty URI");
 	     string::size_type colon = uri.find(':',ns);
 	     if(colon==string::npos)
 		 throw bad_input(OPKELE_CP_ "No scheme specified in URI");
 	     transform(
 		     uri.begin()+ns, uri.begin()+colon+1,
 		     back_inserter(rv), ::tolower );
 	     bool s;
 	     string::size_type ul = uri.find_last_not_of(whitespace)+1;
 	     if(ul <= (colon+3))
 		 throw bad_input(OPKELE_CP_ "Unexpected end of URI being normalized encountered");
 	     if(uri[colon+1]!='/' || uri[colon+2]!='/')
 		 throw bad_input(OPKELE_CP_ "Unexpected input in URI being normalized after scheme component");
 	     if(rv=="http:")
 		 s = false;
 	     else if(rv=="https:")