[Python-checkins] [2.7] bpo-18368: Fix memory leaks in PyOS_StdioReadline() when realloc() fails (GH-12334)

[Victor Stinner]

https://github.com/python/cpython/commit/d9c6564f90ead067c2e288f01825684821b7a129
commit: d9c6564f90ead067c2e288f01825684821b7a129
branch: 2.7
author: stratakis <cstratak at redhat.com>
committer: Victor Stinner <vstinner at redhat.com>
date: 2019-03-19T11:43:20+01:00
summary:

[2.7] bpo-18368: Fix memory leaks in PyOS_StdioReadline() when realloc() fails (GH-12334)

(cherry picked from commit 9ae513caa74a05970458dee17fb995ea49965bb5)

files:
A Misc/NEWS.d/next/Core and Builtins/2019-03-14-17-30-46.bpo-18368.WXaHAo.rst
M Parser/myreadline.c

diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-03-14-17-30-46.bpo-18368.WXaHAo.rst b/Misc/NEWS.d/next/Core and Builtins/2019-03-14-17-30-46.bpo-18368.WXaHAo.rst
new file mode 100644
index 000000000000..7f2fb898fbc6
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-03-14-17-30-46.bpo-18368.WXaHAo.rst	
@@ -0,0 +1 @@
+PyOS_StdioReadline() no longer leaks memory when realloc() fails.
diff --git a/Parser/myreadline.c b/Parser/myreadline.c
index 59db41ab1696..537621402b8d 100644
--- a/Parser/myreadline.c
+++ b/Parser/myreadline.c
@@ -108,7 +108,7 @@ char *
 PyOS_StdioReadline(FILE *sys_stdin, FILE *sys_stdout, char *prompt)
 {
     size_t n;
-    char *p;
+    char *p, *pr;
     n = 100;
     if ((p = (char *)PyMem_MALLOC(n)) == NULL)
         return NULL;
@@ -140,17 +140,29 @@ PyOS_StdioReadline(FILE *sys_stdin, FILE *sys_stdout, char *prompt)
     n = strlen(p);
     while (n > 0 && p[n-1] != '\n') {
         size_t incr = n+2;
-        p = (char *)PyMem_REALLOC(p, n + incr);
-        if (p == NULL)
-            return NULL;
         if (incr > INT_MAX) {
+            PyMem_FREE(p);
             PyErr_SetString(PyExc_OverflowError, "input line too long");
+            return NULL;
+        }
+        pr = (char *)PyMem_REALLOC(p, n + incr);
+        if (pr == NULL) {
+            PyMem_FREE(p);
+            PyErr_NoMemory();
+            return NULL;
         }
+        p = pr;
         if (my_fgets(p+n, (int)incr, sys_stdin) != 0)
             break;
         n += strlen(p+n);
     }
-    return (char *)PyMem_REALLOC(p, n+1);
+    pr = (char *)PyMem_REALLOC(p, n+1);
+    if (pr == NULL) {
+        PyMem_FREE(p);
+        PyErr_NoMemory();
+        return NULL;
+    }
+    return pr;
 }