[PATCH 8/8] Reject bup_getpwuid bup_getgrgid argument overflow

[Rob Browning]

Replace PyArg_ParseTuple "K" checks (which ignore overflow) with
BUP_ASSIGN_PYLONG_TO_INTEGRAL.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>
---
 lib/bup/_helpers.c | 25 ++++++++++++++++---------
 src/bup/pyutil.h   |  4 ++--
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/lib/bup/_helpers.c b/lib/bup/_helpers.c
index 9bfb5e35a..9a8e1555a 100644
--- a/lib/bup/_helpers.c
+++ b/lib/bup/_helpers.c
@@ -1347,13 +1347,16 @@ static PyObject *pwd_struct_to_py(const struct passwd 
*pwd)
 
 static PyObject *bup_getpwuid(PyObject *self, PyObject *args)
 {
-    unsigned long long py_uid;
-    if (!PyArg_ParseTuple(args, "K", &py_uid))
+    PyObject *py_uid = NULL;
+    if (!PyArg_ParseTuple(args, "O", &py_uid))
        return NULL;
     uid_t uid;
-    if (!INTEGRAL_ASSIGNMENT_FITS(&uid, py_uid))
-        return PyErr_Format(PyExc_OverflowError, "uid too large for uid_t");
-
+    int overflow;
+    if (!BUP_ASSIGN_PYLONG_TO_INTEGRAL(&uid, py_uid, &overflow)) {
+        if (overflow)
+            return PyErr_Format(PyExc_OverflowError, "uid too large for 
uid_t");
+        return NULL;
+    }
     errno = 0;
     struct passwd *pwd = getpwuid(uid);
     if (!pwd && errno)
@@ -1395,12 +1398,16 @@ static PyObject *grp_struct_to_py(const struct group 
*grp)
 
 static PyObject *bup_getgrgid(PyObject *self, PyObject *args)
 {
-    unsigned long long py_gid;
-    if (!PyArg_ParseTuple(args, "K", &py_gid))
+    PyObject *py_gid = NULL;
+    if (!PyArg_ParseTuple(args, "O", &py_gid))
        return NULL;
     gid_t gid;
-    if (!INTEGRAL_ASSIGNMENT_FITS(&gid, py_gid))
-        return PyErr_Format(PyExc_OverflowError, "gid too large for gid_t");
+    int overflow;
+    if (!BUP_ASSIGN_PYLONG_TO_INTEGRAL(&gid, py_gid, &overflow)) {
+        if (overflow)
+            return PyErr_Format(PyExc_OverflowError, "gid too large for 
gid_t");
+        return NULL;
+    }
 
     errno = 0;
     struct group *grp = getgrgid(gid);
diff --git a/src/bup/pyutil.h b/src/bup/pyutil.h
index 37f4a100b..93059e985 100644
--- a/src/bup/pyutil.h
+++ b/src/bup/pyutil.h
@@ -18,7 +18,7 @@ int bup_ullong_from_py(unsigned long long *x, PyObject *py, 
const char *name);
 // success returns non-zero.  On failure returns 0 and overflow will
 // be non-zero if there was an overflow, otherwise a python exception
 // will be pending.
-#define BUP_ASSIGN_PYLONG_TO_INTEGRAL (dest, pylong, overflow)          \
+#define BUP_ASSIGN_PYLONG_TO_INTEGRAL(dest, pylong, overflow)           \
     ({                                                                  \
          int result = 0;                                                \
          int pending_overflow = 0;                                      \
@@ -36,7 +36,7 @@ int bup_ullong_from_py(unsigned long long *x, PyObject *py, 
const char *name);
          } else {                                                       \
              const unsigned long long tmp =                             \
                  PyLong_AsUnsignedLongLong(pylong);                     \
-             if (tmp == -1 && PyErr_Occurred()                          \
+             if (tmp == (unsigned long long) -1 && PyErr_Occurred()     \
                  && PyErr_ExceptionMatches(PyExc_OverflowError))        \
                  pending_overflow = 2;                                  \
              else {                                                     \
-- 
2.39.2