File wordexp-wrde-reuse.patch of Package glibc.42452
From d5409a1be010699794264162c551ba60f05ee6c3 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Thu, 15 Jan 2026 10:32:19 -0300
Subject: [PATCH] posix: Reset wordexp_t fields with WRDE_REUSE (CVE-2025-15281
/ BZ 33814)
The wordexp fails to properly initialize the input wordexp_t when
WRDE_REUSE is used. The wordexp_t struct is properly freed, but
reuses the old wc_wordc value and updates the we_wordv in the
wrong position. A later wordfree will then call free with an
invalid pointer.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 80cc58ea2de214f85b0a1d902a3b668ad2ecb302)
---
NEWS | 6 +++
posix/Makefile | 11 +++++
posix/tst-wordexp-reuse.c | 89 +++++++++++++++++++++++++++++++++++++++
posix/wordexp.c | 2 +
4 files changed, 108 insertions(+)
create mode 100644 posix/tst-wordexp-reuse.c
diff --git a/posix/Makefile b/posix/Makefile
index 1fc0f565af..7db396fbe6 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -328,6 +328,7 @@ tests := \
tst-wait4 \
tst-waitid \
tst-wordexp-nocmd \
+ tst-wordexp-reuse \
tstgetopt \
# tests
@@ -453,6 +454,8 @@ generated += \
tst-rxspencer-no-utf8.mtrace \
tst-vfork3-mem.out \
tst-vfork3.mtrace \
+ tst-wordexp-reuse-mem.out \
+ tst-wordexp-reuse.mtrace \
wordexp-tst.out \
# generated
@@ -484,6 +487,7 @@ tests-special += \
$(objpfx)tst-pcre-mem.out \
$(objpfx)tst-rxspencer-no-utf8-mem.out \
$(objpfx)tst-vfork3-mem.out \
+ $(objpfx)tst-wordexp-reuse.out \
# tests-special
endif
@@ -765,3 +769,10 @@ $(objpfx)posix-conf-vars-def.h: $(..)scripts/gen-posix-conf-vars.awk \
$(make-target-directory)
$(AWK) -f $(filter-out Makefile, $^) > $@.tmp
mv -f $@.tmp $@
+
+tst-wordexp-reuse-ENV += MALLOC_TRACE=$(objpfx)tst-wordexp-reuse.mtrace \
+ LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so
+
+$(objpfx)tst-wordexp-reuse-mem.out: $(objpfx)tst-wordexp-reuse.out
+ $(common-objpfx)malloc/mtrace $(objpfx)tst-wordexp-reuse.mtrace > $@; \
+ $(evaluate-test)
diff --git a/posix/tst-wordexp-reuse.c b/posix/tst-wordexp-reuse.c
new file mode 100644
index 0000000000..3926b9f557
--- /dev/null
+++ b/posix/tst-wordexp-reuse.c
@@ -0,0 +1,89 @@
+/* Test for wordexp with WRDE_REUSE flag.
+ Copyright (C) 2026 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 <wordexp.h>
+#include <mcheck.h>
+
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+ mtrace ();
+
+ {
+ wordexp_t p = { 0 };
+ TEST_COMPARE (wordexp ("one", &p, 0), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[0], "one");
+ TEST_COMPARE (wordexp ("two", &p, WRDE_REUSE), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[0], "two");
+ wordfree (&p);
+ }
+
+ {
+ wordexp_t p = { .we_offs = 2 };
+ TEST_COMPARE (wordexp ("one", &p, 0), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[0], "one");
+ TEST_COMPARE (wordexp ("two", &p, WRDE_REUSE | WRDE_DOOFFS), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[p.we_offs + 0], "two");
+ wordfree (&p);
+ }
+
+ {
+ wordexp_t p = { 0 };
+ TEST_COMPARE (wordexp ("one", &p, 0), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[0], "one");
+ TEST_COMPARE (wordexp ("two", &p, WRDE_REUSE | WRDE_APPEND), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[0], "two");
+ wordfree (&p);
+ }
+
+ {
+ wordexp_t p = { .we_offs = 2 };
+ TEST_COMPARE (wordexp ("one", &p, WRDE_DOOFFS), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[p.we_offs + 0], "one");
+ TEST_COMPARE (wordexp ("two", &p, WRDE_REUSE
+ | WRDE_DOOFFS), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[p.we_offs + 0], "two");
+ wordfree (&p);
+ }
+
+ {
+ wordexp_t p = { .we_offs = 2 };
+ TEST_COMPARE (wordexp ("one", &p, WRDE_DOOFFS), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[p.we_offs + 0], "one");
+ TEST_COMPARE (wordexp ("two", &p, WRDE_REUSE
+ | WRDE_DOOFFS | WRDE_APPEND), 0);
+ TEST_COMPARE (p.we_wordc, 1);
+ TEST_COMPARE_STRING (p.we_wordv[p.we_offs + 0], "two");
+ wordfree (&p);
+ }
+
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/posix/wordexp.c b/posix/wordexp.c
index 994d79161f..5c5863b51b 100644
--- a/posix/wordexp.c
+++ b/posix/wordexp.c
@@ -2216,7 +2216,9 @@ wordexp (const char *words, wordexp_t *pwordexp, int flags)
{
/* Minimal implementation of WRDE_REUSE for now */
wordfree (pwordexp);
+ old_word.we_wordc = 0;
old_word.we_wordv = NULL;
+ pwordexp->we_wordc = 0;
}
if ((flags & WRDE_APPEND) == 0)
--
2.52.0
