Backport fixes for the code that decodes octal escapes (and for PyString

also hex escapes) -- this was reaching beyond the end of the input string
buffer, even though it is not supposed to be \0-terminated.
This has no visible effect but is clearly the correct thing to do.
(In 3.0 it had a visible effect after removing ob_sstate from PyString.)

diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 22b50d5f76d0aaa8c33c947debdbdc475b098464..3c140229812d68ca5ad241e04f38bdef8a720588 100644 (file)
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -616,16 +616,18 @@ PyObject *PyString_DecodeEscape(const char *s,
                case '0': case '1': case '2': case '3':
                case '4': case '5': case '6': case '7':
                        c = s[-1] - '0';
-                       if ('0' <= *s && *s <= '7') {
+                       if (s < end && '0' <= *s && *s <= '7') {
                                c = (c<<3) + *s++ - '0';
-                               if ('0' <= *s && *s <= '7')
+                               if (s < end && '0' <= *s && *s <= '7')
                                        c = (c<<3) + *s++ - '0';
                        }
                        *p++ = c;
                        break;
                case 'x':
-                       if (isxdigit(Py_CHARMASK(s[0]))
-                           && isxdigit(Py_CHARMASK(s[1]))) {
+                       if (s+1 < end &&
+                            isxdigit(Py_CHARMASK(s[0])) &&
+                           isxdigit(Py_CHARMASK(s[1])))
+                        {
                                unsigned int x = 0;
                                c = Py_CHARMASK(*s);
                                s++;

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 26aa7533bab43440c2cbf028e00f5e9d09f21f16..1f6f738c6df8201225d95026ecef7964d126c2cc 100644 (file)
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -2081,7 +2081,10 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
         startinpos = s-starts;
         /* \ - Escapes */
         s++;
-        switch (*s++) {
+        c = *s++;
+        if (s > end)
+            c = '\0'; /* Invalid after \ */
+        switch (c) {
 
         /* \x escapes */
         case '\n': break;
@@ -2100,9 +2103,9 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
         case '0': case '1': case '2': case '3':
         case '4': case '5': case '6': case '7':
             x = s[-1] - '0';
-            if ('0' <= *s && *s <= '7') {
+            if (s < end && '0' <= *s && *s <= '7') {
                 x = (x<<3) + *s++ - '0';
-                if ('0' <= *s && *s <= '7')
+                if (s < end && '0' <= *s && *s <= '7')
                     x = (x<<3) + *s++ - '0';
             }
             *p++ = x;