vfprintf: Fix memory with large width and precision [BZ #19931]

Free a previously allocated work buffer if it is not large enough.
2025-08-08 17:42:12 +03:00 · 2016-04-25 14:10:26 +02:00
parent a5507dfa60
commit fdcf1c9480
4 changed files with 134 additions and 5 deletions
--- a/stdio-common/tst-vfprintf-width-prec.c
+++ b/stdio-common/tst-vfprintf-width-prec.c
@@ -0,0 +1,107 @@
+/* Test for memory leak with large width and precision.
+   Copyright (C) 1991-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <mcheck.h>
+#include <stdio.h>
+#include <sys/resource.h>
+#include <wchar.h>
+
+static int
+do_test (void)
+{
+  mtrace ();
+
+  int ret;
+  {
+    char *result;
+    ret = asprintf (&result, "%133000.133001x", 17);
+    if (ret < 0)
+      {
+        printf ("error: asprintf: %m\n");
+        return 1;
+      }
+    free (result);
+  }
+  {
+    wchar_t *result = calloc (ret + 1, sizeof (wchar_t));
+    if (result == NULL)
+      {
+        printf ("error: calloc (%d, %zu): %m", ret + 1, sizeof (wchar_t));
+        return 1;
+      }
+
+    ret = swprintf (result, ret + 1, L"%133000.133001x", 17);
+    if (ret < 0)
+      {
+        printf ("error: swprintf: %d (%m)\n", ret);
+        return 1;
+      }
+    free (result);
+  }
+
+  /* Limit the size of the process, so that the second allocation will
+     fail.  */
+  {
+    struct rlimit limit;
+    if (getrlimit (RLIMIT_AS, &limit) != 0)
+      {
+        printf ("getrlimit (RLIMIT_AS) failed: %m\n");
+        return 1;
+      }
+    long target = 200 * 1024 * 1024;
+    if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > target)
+      {
+        limit.rlim_cur = target;
+        if (setrlimit (RLIMIT_AS, &limit) != 0)
+          {
+            printf ("setrlimit (RLIMIT_AS) failed: %m\n");
+            return 1;
+          }
+      }
+  }
+
+  {
+    char *result;
+    ret = asprintf (&result, "%133000.999999999x", 17);
+    if (ret >= 0)
+      {
+        printf ("error: asprintf: incorrect result %d\n", ret);
+        return 1;
+      }
+  }
+  {
+    wchar_t result[100];
+    if (result == NULL)
+      {
+        printf ("error: calloc (%d, %zu): %m", ret + 1, sizeof (wchar_t));
+        return 1;
+      }
+
+    ret = swprintf (result, 100, L"%133000.999999999x", 17);
+    if (ret >= 0)
+      {
+        printf ("error: swprintf: incorrect result %d\n", ret);
+        return 1;
+      }
+  }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"