vgetargskeywords: Verify kwlist has the required length while parsing

the format, instead of waiting until after we can overindex it by
mistake.

diff --git a/Python/getargs.c b/Python/getargs.c
index 3306eb6344cccfa404a63f8d5162b1f6603deae1..8b6b3067b79a88d95df8d3e8efeea84607afbefc 100644 (file)
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1032,9 +1032,9 @@ vgetargskeywords(PyObject *args, PyObject *keywords, char *format,
        char *fname, *message;
        int min, max;
        char *formatsave;
-       int i, len, nargs, nkeywords;
+       int i, len, nargs, nkeywords, nkwlist;
        char *msg, *ks, **p;
-       int nkwlist, pos, match, converted;
+       int pos, match, converted;
        PyObject *key, *value;
 
        assert(args != NULL && PyTuple_Check(args));
@@ -1048,15 +1048,24 @@ vgetargskeywords(PyObject *args, PyObject *keywords, char *format,
           name <- routine name, if any (else NULL).
           min <- # of required arguments, or -1 if all are required.
           max <- most arguments (required + optional).
+          Check that kwlist has a non-NULL entry for each arg.
           Raise error if a tuple arg spec is found.
        */
        fname = message = NULL;
        formatsave = format;
+       p = kwlist;
        min = -1;
        max = 0;
        while ((i = *format++) != '\0') {
-               if (isalpha(i) && i != 'e')
+               if (isalpha(i) && i != 'e') {
                        max++;
+                       if (*p == NULL) {
+                               /* kwlist is too short */
+                               PyErr_BadInternalCall();
+                               return 0;
+                       }
+                       p++;
+               }
                else if (i == '|')
                        min = max;
                else if (i == ':') {
@@ -1072,13 +1081,19 @@ vgetargskeywords(PyObject *args, PyObject *keywords, char *format,
                      "tuple found in format when using keyword arguments");
                        return 0;
                }
-       }       
+       }
+       format = formatsave;
+       if (*p != NULL) {
+               /* kwlist is too long */
+               PyErr_BadInternalCall();
+               return 0;
+       }
        if (min < 0) {
                /* All arguments are required. */
                min = max;
        }
-       format = formatsave;
 
+       nkwlist = max;
        nargs = PyTuple_GET_SIZE(args);
        nkeywords = keywords == NULL ? 0 : PyDict_Size(keywords);
 
@@ -1103,9 +1118,11 @@ vgetargskeywords(PyObject *args, PyObject *keywords, char *format,
        }
 
        /* required arguments missing from args can be supplied by keyword 
-          arguments */
+          arguments; set len to the number of posiitional arguments, and,
+          if that's less than the minimum required, add in the number of
+          required arguments that are supplied by keywords */
        len = nargs;
-       if (keywords && nargs < min) {
+       if (nkeywords > 0 && nargs < min) {
                for (i = nargs; i < min; i++) {
                        if (PyDict_GetItemString(keywords, kwlist[i]))
                                len++;
@@ -1118,7 +1135,6 @@ vgetargskeywords(PyObject *args, PyObject *keywords, char *format,
           is a little confusing with keywords since keyword arguments
           which are supplied, but don't match the required arguments
           are not included in the "%d given" part of the message */
-
        if (len < min || max < len) {
                if (message == NULL) {
                        sprintf(msgbuf,
@@ -1151,18 +1167,6 @@ vgetargskeywords(PyObject *args, PyObject *keywords, char *format,
        if (nkeywords == 0)
                return 1; 
 
-       /* make sure the number of keywords in the keyword list matches the 
-          number of items in the format string */
-       nkwlist = 0;
-       p =  kwlist;
-       while (*p++)
-               nkwlist++;
-       if (nkwlist != max) {
-               PyErr_SetString(PyExc_SystemError,
-         "number of items in format string and keyword list do not match");
-               return 0;
-       }                 
-
        /* convert the keyword arguments; this uses the format 
           string where it was left after processing args */
        converted = 0;