Handle "filename*" field in MP header

apache2/msc_multipart.c

@@ -20,6 +20,9 @@
 #include "msc_util.h"
 #include "msc_parsers.h"
 
+static const char* mime_charset_special = "!#$%&+-^_`{}~";
+static const char* attr_char_special = "!#$&+-.^_`~";
+
 void validate_quotes(modsec_rec *msr, char *data, char quote)  {
     assert(msr != NULL);
     int i, len;
@@ -85,6 +88,7 @@ static int multipart_parse_content_disposition(modsec_rec *msr, char *c_d_value)
     assert(msr != NULL);
     assert(c_d_value != NULL);
     char *p = NULL, *t = NULL;
+    char *filenameStar = NULL;
 
     /* accept only what we understand */
     if (strncmp(c_d_value, "form-data", 9) != 0) {
@@ -130,7 +134,41 @@ static int multipart_parse_content_disposition(modsec_rec *msr, char *c_d_value)
          */
 
         char quote = '\0';
-        if ((*p == '"') || (*p == '\'')) {
+        if (name == "filename*") {
+            /* filename*=charset'[optional-language]'filename */
+            /* Read beyond the charset and the optional language*/
+            const char* start_of_charset = p;
+            while ((*p != '\0') && (isalnum(*p) || (strchr(mime_charset_special, *p)))) {
+                p++;
+            }
+            if ((*p != '\'') || (p == start_of_charset)) {
+                return -16; // Must be at least one legit char before ' for start of language
+            }
+            p++;
+            while ((*p != '\0') && (*p != '\'')) {
+                p++;
+            }
+            if (*p != '\'') {
+                return -17; // Single quote for end-of-language not found
+            }
+            p++;
+
+            /* Now read what should be the actual filename */
+            const char* start_of_filename = p;
+            while ((*p != '\0') && (*p != ';')) {
+                if (*p == '%') {
+                    if ((*(p+1) == '\0') || (!isxdigit(*(p+1))) || (!isxdigit(*(p+2)))) {
+                        return -18;
+                    }
+                    p += 3;
+                } else if (isalnum(*p) || strchr(attr_char_special, *p)) {
+                    p++;
+                } else {
+                    return -19;
+                }
+            }
+            value = apr_pmemdup(msr->mp, start_of_filename, p - start_of_filename);
+        } else if ((*p == '"') || (*p == '\'')) {
             /* quoted */
             quote = *p; // remember which quote character was used for the value
 
@@ -205,8 +243,7 @@ static int multipart_parse_content_disposition(modsec_rec *msr, char *c_d_value)
                     log_escape_nq(msr->mp, value));
             }
         }
-        else
-        if (strcmp(name, "filename") == 0) {
+        else if (strcmp(name, "filename") == 0) {
 
             validate_quotes(msr, value, quote);
 
@@ -223,6 +260,17 @@ static int multipart_parse_content_disposition(modsec_rec *msr, char *c_d_value)
                 msr_log(msr, 9, "Multipart: Content-Disposition filename: %s",
                     log_escape_nq(msr->mp, value));
             }
+        } else if (strcmp(name, "filename*") == 0) {
+            if (filenameStar != NULL && strlen(filenameStar) != 0) {
+                msr_log(msr, 4,
+                    "Multipart: Warning: Duplicate Content-Disposition filename*: %s.",  log_escape_nq(msr->mp, value));
+                return -20;
+            }
+            filenameStar = apr_pstrdup(msr->mp, value);
+            if (msr->txcfg->debuglog_level >= 9) {
+                msr_log(msr, 9, "Multipart: Content-Disposition filename*: %s.",
+                    log_escape_nq(msr->mp, value));
+            }
         }
         else return -11;