1 files changed, 95 insertions, 1 deletions

diff --git a/src/misc.h b/src/misc.h
index b2d4fe6e..e52b93bd 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -2,6 +2,7 @@
 #define __DILLO_MISC_H__
 
 #include <stddef.h>     /* for size_t */
+#include <ctype.h>      /* iscntrl, isascii */
 
 
 #ifdef __cplusplus
@@ -17,12 +18,105 @@ int a_Misc_content_type_check(const char *EntryType, const char *DetectedType);
 void a_Misc_parse_content_type(const char *str, char **major, char **minor,
                                char **charset);
 int a_Misc_content_type_cmp(const char* ct1, const char *ct2);
-void a_Misc_parse_content_disposition(const char *disposition, char **type, char **filename);
 int a_Misc_parse_geometry(char *geom, int *x, int *y, int *w, int *h);
 int a_Misc_parse_search_url(char *source, char **label, char **urlstr);
 char *a_Misc_encode_base64(const char *in);
 Dstr *a_Misc_file2dstr(const char *filename);
 
+/**
+ * Parse Content-Disposition string, e.g., "attachment; filename="file name.jpg"".
+ * Content-Disposition is defined in RFC 6266
+ */
+static inline void a_Misc_parse_content_disposition(const char *disposition, char **type, char **filename)
+{
+   static const char tspecials_space[] = "()<>@,;:\\\"/[]?= ";
+   const char terminators[] = " ;\t";
+   const char *str, *s;
+
+   if (type)
+      *type = NULL;
+   if (filename)
+      *filename = NULL;
+   if (!(str = disposition))
+      return;
+
+   for (s = str; *s && d_isascii((uchar_t)*s) && !iscntrl((uchar_t)*s) &&
+      !strchr(tspecials_space, *s); s++) ;
+   if (type && !(s == str))
+      *type = dStrndup(str, s - str);
+
+   if (!*type) {
+      return;
+   }
+
+   if (!strchr(terminators, *s)) {
+      *type = NULL;
+      return;
+   }
+
+   if (*s == ';') {
+      bool_t quoted = FALSE;
+      const char key[] = "filename";
+
+      if ((s = dStriAsciiStr(str, key)) &&
+          (s == str || strchr(terminators, s[-1]))) {
+         s += sizeof(key) - 1;
+         for ( ; *s == ' ' || *s == '\t'; ++s);
+         if (*s == '=') {
+            size_t len = 0;
+            for (++s; *s == ' ' || *s == '\t'; ++s);
+            if (*s == '"') {
+               quoted = TRUE;
+               s++;
+               for ( ; *s == '.'; ++s);
+               bool_t escaped = FALSE;
+               const char *c;
+               unsigned int maxlen = strlen(s);
+               for (c = s; !(*c == '"' && !escaped); c++) {
+                  if ((len = c - s + 1) > maxlen) {
+                     return;
+                  }
+                  escaped = *c == '\\';
+               }
+               *filename = dStrndup(s, len);
+            } else {
+               for ( ; *s == '.'; ++s);
+               if ((len = strcspn(s, terminators))) {
+                  *filename = dStrndup(s, len);
+               }
+            }
+
+            const char invalid_characters[] = "/\\|~";
+            char *s = *filename, *d = *filename;
+
+            for ( ; s < *filename + len; s++) {
+               if (strchr(invalid_characters, *s)) {
+                  // If this is a backslash preceding a quote, we want to just
+                  // skip past it without advancing the destination pointer or
+                  // copying anything.
+                  if (!(*s == '\\' && *(s+1) == '"')) {
+                     *d = '_';
+                     d++;
+                  }
+               } else if (!quoted && (!d_isascii((uchar_t)*s) || *s == '=')) {
+                  *filename = NULL;
+                  return;
+               } else {
+                  *d = *s;
+                  d++;
+               }
+            }
+
+            // Truncate filename to deal with the string being shorter if we
+            // skipped over any backslash characters in the above loop
+            if (s != d) {
+               *d = '\0';
+            }
+         }
+      }
+   }
+}
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */