Fix memory leak in __printf_fp_l (bug 26215).

__printf_fp_l has a memory leak in the case of some I/O errors, where
both buffer and wbuffer have been malloced but the handling of I/O
errors only frees wbuffer.  This patch fixes this by moving the
declaration of buffer to an outer scope and ensuring that it is freed
when wbuffer is freed.

Tested for x86_64 and x86.

1 files changed, 34 insertions, 0 deletions

diff --git a/stdio-common/tst-printf-fp-leak.c b/stdio-common/tst-printf-fp-leak.c
new file mode 100644
index 0000000000..da11a486dd
--- /dev/null
+++ b/stdio-common/tst-printf-fp-leak.c
@@ -0,0 +1,34 @@
+/* Test memory leak in __printf_fp_l (bug 26215).
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <mcheck.h>
+#include <stdio.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+  mtrace ();
+  FILE *fp = fopen ("/dev/full", "w");
+  TEST_VERIFY_EXIT (fp != NULL);
+  TEST_COMPARE (fprintf (fp, "%.65536f", 1.0), -1);
+  fclose (fp);
+  return 0;
+}
+
+#include <support/test-driver.c>