Fix getMultipartBoundary() issues and add tests for it.

chronos/apps/http/multipart.nim

@@ -423,19 +423,36 @@ func getMultipartBoundary*(ch: openarray[string]): HttpResult[string] =
         return err("Content-Type is not multipart")
       if len(mparts) < 2:
         return err("Content-Type missing boundary value")
-      let stripped = strip(mparts[1])
-      if not(stripped.toLowerAscii().startsWith("boundary")):
-        return err("Incorrect Content-Type boundary format")
-      let bparts = stripped.split("=")
-      if len(bparts) < 2:
-        err("Missing Content-Type boundary")
+
+      let index =
+        block:
+          var idx = 0
+          for i in 1 ..< len(mparts):
+            let stripped = strip(mparts[i])
+            if stripped.toLowerAscii().startsWith("boundary="):
+              idx = i
+              break
+          idx
+
+      if index == 0:
+        err("Missing Content-Type boundary key")
       else:
-        let candidate = strip(bparts[1])
-        if len(candidate) > 70:
-          err("Content-Type boundary must be less then 70 characters")
+        let stripped = strip(mparts[index])
+        let bparts = stripped.split("=", 1)
+        if len(bparts) < 2:
+          err("Missing Content-Type boundary")
         else:
-          for ch in candidate:
-            if ch notin {'a'..'z', 'A' .. 'Z', '0' .. '9',
-                         '\'' .. ')', '+' .. '/', ':', '=', '?', '_'}:
-              return err("Content-Type boundary alphabat incorrect")
-          ok(candidate)
+          if bparts[0].toLowerAscii() != "boundary":
+            err("Missing boundary key")
+          else:
+            let candidate = strip(bparts[1])
+            if len(candidate) == 0:
+              err("Content-Type boundary must be at least 1 character size")
+            elif len(candidate) > 70:
+              err("Content-Type boundary must be less then 70 characters")
+            else:
+              for ch in candidate:
+                if ch notin {'a' .. 'z', 'A' .. 'Z', '0' .. '9',
+                             '\'' .. ')', '+' .. '/', ':', '=', '?', '_'}:
+                  return err("Content-Type boundary alphabet incorrect")
+              ok(candidate)

tests/testhttpserver.nim

@@ -680,6 +680,80 @@ suite "HTTP server testing suite":
 
     check waitFor(testHTTPS2(initTAddress("127.0.0.1:30080"))) == true
 
+
+  test "Content-Type multipart boundary test":
+    const AllowedCharacters = {
+      'a' .. 'z', 'A' .. 'Z', '0' .. '9',
+      '\'', '(', ')', '+', '_', ',', '-', '.' ,'/', ':', '=', '?'
+    }
+
+    const FailureVectors = [
+      "",
+      "multipart/byteranges; boundary=A",
+      "multipart/form-data;",
+      "multipart/form-data; boundary",
+      "multipart/form-data; boundary=",
+      "multipart/form-data; boundaryMore=A",
+      "multipart/form-data; charset=UTF-8; boundary",
+      "multipart/form-data; charset=UTF-8; boundary=",
+      "multipart/form-data; charset=UTF-8; boundary =",
+      "multipart/form-data; charset=UTF-8; boundary= ",
+      "multipart/form-data; charset=UTF-8; boundaryMore=",
+      "multipart/form-data; charset=UTF-8; boundaryMore=A",
+      "multipart/form-data; charset=UTF-8; boundaryMore=AAAAAAAAAAAAAAAAAAAA" &
+      "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
+    ]
+
+    const SuccessVectors = [
+      ("multipart/form-data; boundary=A", "A"),
+      ("multipart/form-data; charset=UTF-8; boundary=B", "B"),
+      ("multipart/form-data; charset=UTF-8; boundary=--------------------" &
+       "--------------------------------------------------", "-----------" &
+       "-----------------------------------------------------------"),
+      ("multipart/form-data; boundary=--------------------" &
+       "--------------------------------------------------", "-----------" &
+       "-----------------------------------------------------------"),
+      ("multipart/form-data; boundary=--------------------" &
+       "--------------------------------------------------; charset=UTF-8",
+       "-----------------------------------------------------------------" &
+       "-----"),
+      ("multipart/form-data; boundary=ABCDEFGHIJKLMNOPQRST" &
+       "UVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()+_,-.; charset=UTF-8",
+       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()" &
+       "+_,-."),
+      ("multipart/form-data; boundary=ABCDEFGHIJKLMNOPQRST" &
+       "UVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()+?=:/; charset=UTF-8",
+       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()" &
+       "+?=:/"),
+      ("multipart/form-data; charset=UTF-8; boundary=ABCDEFGHIJKLMNOPQRST" &
+       "UVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()+_,-.",
+       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()" &
+       "+_,-."),
+      ("multipart/form-data; charset=UTF-8; boundary=ABCDEFGHIJKLMNOPQRST" &
+       "UVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()+?=:/",
+       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'()" &
+       "+?=:/")
+    ]
+
+    for i in 0 ..< 256:
+      let boundary = "multipart/form-data; boundary=" & $char(i)
+      if char(i) in AllowedCharacters:
+        check getMultipartBoundary([boundary]).isOk()
+      else:
+        check getMultipartBoundary([boundary]).isErr()
+
+    check:
+      getMultipartBoundary([]).isErr()
+      getMultipartBoundary(["multipart/form-data; boundary=A",
+                            "multipart/form-data; boundary=B"]).isErr()
+    for item in FailureVectors:
+      check getMultipartBoundary([item]).isErr()
+    for item in SuccessVectors:
+      let res = getMultipartBoundary([item[0]])
+      check:
+        res.isOk()
+        item[1] == res.get()
+
   test "Leaks test":
     check:
       getTracker("async.stream.reader").isLeaked() == false