From: Rob Browning <rlb@defaultvalue.org>
Date: Fri, 8 Oct 2021 15:47:28 +0000 (-0500)
Subject: bitmatch: check for overflow via intprops
X-Git-Url: https://arthur.barton.de/gitweb/?p=bup.git;a=commitdiff_plain;h=8659febe534245ed8a5299637aa4ee0961aa1011

bitmatch: check for overflow via intprops

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
---

diff --git a/lib/bup/_helpers.c b/lib/bup/_helpers.c
index fc1b69b..b5a3c79 100644
--- a/lib/bup/_helpers.c
+++ b/lib/bup/_helpers.c
@@ -620,8 +620,14 @@ static PyObject *bitmatch(PyObject *self, PyObject *args)
 	}
     }
     
-    assert(byte <= (INT_MAX >> 3));
-    return Py_BuildValue("i", byte*8 + bit);
+    unsigned long long result;
+    if (!INT_MULTIPLY_OK(byte, 8, &result)
+        || !INT_ADD_OK(result, bit, &result))
+    {
+        PyErr_Format(PyExc_OverflowError, "bitmatch bit count too large");
+        return NULL;
+    }
+    return PyLong_FromUnsignedLongLong(result);
 }