Digest auth: escape user names with \ or " in them

When sending the HTTP Authorization: header for digest, the user name
needs to be escaped if it contains a double-quote or backslash.

Test 1229 was added to verify

Reported and fixed by: Nach M. S
Bug: http://curl.haxx.se/bug/view.cgi?id=1230

lib/http_digest.c

@@ -267,6 +267,38 @@ static void md5_to_ascii(unsigned char *source, /* 16 bytes */
     snprintf((char *)&dest[i*2], 3, "%02x", source[i]);
 }
 
+/* Perform quoted-string escaping as described in RFC2616 and its errata */
+static char *string_quoted(const char *source)
+{
+  char *dest, *d;
+  const char *s = source;
+  size_t n = 1; /* null terminator */
+
+  /* Calculate size needed */
+  while(*s) {
+    ++n;
+    if(*s == '"' || *s == '\\') {
+      ++n;
+    }
+    ++s;
+  }
+
+  dest = (char *)malloc(n);
+  if(dest) {
+    s = source;
+    d = dest;
+    while(*s) {
+      if(*s == '"' || *s == '\\') {
+        *d++ = '\\';
+      }
+      *d++ = *s++;
+    }
+    *d = 0;
+  }
+
+  return dest;
+}
+
 CURLcode Curl_output_digest(struct connectdata *conn,
                             bool proxy,
                             const unsigned char *request,
@@ -289,6 +321,7 @@ CURLcode Curl_output_digest(struct connectdata *conn,
   char **allocuserpwd;
   size_t userlen;
   const char *userp;
+  char *userp_quoted;
   const char *passwdp;
   struct auth *authp;
 
@@ -468,7 +501,18 @@ CURLcode Curl_output_digest(struct connectdata *conn,
 
     Authorization: Digest username="testuser", realm="testrealm", \
     nonce="1053604145", uri="/64", response="c55f7f30d83d774a3d2dcacf725abaca"
+
+    Digest parameters are all quoted strings.  Username which is provided by
+    the user will need double quotes and backslashes within it escaped.  For
+    the other fields, this shouldn't be an issue.  realm, nonce, and opaque
+    are copied as is from the server, escapes and all.  cnonce is generated
+    with web-safe characters.  uri is already percent encoded.  nc is 8 hex
+    characters.  algorithm and qop with standard values only contain web-safe
+    chracters.
   */
+  userp_quoted = string_quoted(userp);
+  if(!*userp_quoted)
+    return CURLE_OUT_OF_MEMORY;
 
   if(d->qop) {
     *allocuserpwd =
@@ -482,7 +526,7 @@ CURLcode Curl_output_digest(struct connectdata *conn,
                "qop=%s, "
                "response=\"%s\"",
                proxy?"Proxy-":"",
-               userp,
+               userp_quoted,
                d->realm,
                d->nonce,
                uripath, /* this is the PATH part of the URL */
@@ -505,12 +549,13 @@ CURLcode Curl_output_digest(struct connectdata *conn,
                "uri=\"%s\", "
                "response=\"%s\"",
                proxy?"Proxy-":"",
-               userp,
+               userp_quoted,
                d->realm,
                d->nonce,
                uripath, /* this is the PATH part of the URL */
                request_digest);
   }
+  free(userp_quoted);
   if(!*allocuserpwd)
     return CURLE_OUT_OF_MEMORY;
 

tests/data/Makefile.am

@@ -93,7 +93,7 @@ test1200 test1201 test1202 test1203 test1204 test1205 test1206 test1207 \
 test1208 test1209 test1210 test1211 test1212 test1213 test1214 test1215 \
 test1216 test1217 test1218 test1219 \
 test1220 test1221 test1222 test1223 test1224 test1225 test1226 test1227 \
-test1228 \
+test1228 test1229 \
 \
 test1300 test1301 test1302 test1303 test1304 test1305 test1306 test1307 \
 test1308 test1309 test1310 test1311 test1312 test1313 test1314 test1315 \

tests/data/test1229

@@ -0,0 +1,82 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+HTTP Digest auth
+</keywords>
+</info>
+# Server-side
+<reply>
+<data>
+HTTP/1.1 401 Authorization Required swsclose
+Server: Apache/1.3.27 (Darwin) PHP/4.1.2
+WWW-Authenticate: Digest realm="testrealm", nonce="1053604145"
+Content-Type: text/html; charset=iso-8859-1
+Content-Length: 26
+
+This is not the real page
+</data>
+
+# This is supposed to be returned when the server gets a
+# Authorization: Digest line passed-in from the client
+<data1000>
+HTTP/1.1 200 OK swsclose
+Server: Apache/1.3.27 (Darwin) PHP/4.1.2
+Content-Type: text/html; charset=iso-8859-1
+Content-Length: 23
+
+This IS the real page!
+</data1000>
+
+<datacheck>
+HTTP/1.1 401 Authorization Required swsclose
+Server: Apache/1.3.27 (Darwin) PHP/4.1.2
+WWW-Authenticate: Digest realm="testrealm", nonce="1053604145"
+Content-Type: text/html; charset=iso-8859-1
+Content-Length: 26
+
+HTTP/1.1 200 OK swsclose
+Server: Apache/1.3.27 (Darwin) PHP/4.1.2
+Content-Type: text/html; charset=iso-8859-1
+Content-Length: 23
+
+This IS the real page!
+</datacheck>
+
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+<features>
+crypto
+</features>
+ <name>
+HTTP with Digest authorization with user name needing escape
+ </name>
+ <command>
+http://%5cuser%22:password@%HOSTIP:%HTTPPORT/1229 --digest
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET /1229 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+GET /1229 HTTP/1.1
+Authorization: Digest username="\\user\"", realm="testrealm", nonce="1053604145", uri="/1229", response="f2694d426040712584c156d3de72b8d6"
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+</protocol>
+</verify>
+</testcase>