[Python-checkins] bpo-36856: Handle possible overflow in faulthandler_stack_overflow (GH-13205)

[Miss Islington (bot)]

https://github.com/python/cpython/commit/1062cf71faa14b90185cf159877083910df10f27
commit: 1062cf71faa14b90185cf159877083910df10f27
branch: 3.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2019-05-27T17:14:21-07:00
summary:

bpo-36856: Handle possible overflow in faulthandler_stack_overflow (GH-13205)

(cherry picked from commit 6236c9823ef3e8e2229b0598d3d8189adf5e00f2)

Co-authored-by: Xi Ruoyao <xry111 at mengyan1223.wang>

files:
M Modules/faulthandler.c

diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index ec5192832ce0..0dbd5a3342b0 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -1120,13 +1120,26 @@ faulthandler_stack_overflow(PyObject *self)
 {
     size_t depth, size;
     uintptr_t sp = (uintptr_t)&depth;
-    uintptr_t stop;
+    uintptr_t stop, lower_limit, upper_limit;
 
     faulthandler_suppress_crash_report();
     depth = 0;
-    stop = stack_overflow(sp - STACK_OVERFLOW_MAX_SIZE,
-                          sp + STACK_OVERFLOW_MAX_SIZE,
-                          &depth);
+
+    if (STACK_OVERFLOW_MAX_SIZE <= sp) {
+        lower_limit = sp - STACK_OVERFLOW_MAX_SIZE;
+    }
+    else {
+        lower_limit = 0;
+    }
+
+    if (UINTPTR_MAX - STACK_OVERFLOW_MAX_SIZE >= sp) {
+        upper_limit = sp + STACK_OVERFLOW_MAX_SIZE;
+    }
+    else {
+        upper_limit = UINTPTR_MAX;
+    }
+
+    stop = stack_overflow(lower_limit, upper_limit, &depth);
     if (sp < stop)
         size = stop - sp;
     else