File wordexp-wrde-reuse.patch of Package glibc.42995
From 28eb5caf895ced5d895cb02757e109004a2d33e5 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 | 5 +++
posix/Makefile | 17 ++++++--
posix/tst-wordexp-reuse.c | 89 +++++++++++++++++++++++++++++++++++++++
posix/wordexp.c | 2 +
4 files changed, 109 insertions(+), 4 deletions(-)
create mode 100644 posix/tst-wordexp-reuse.c
diff --git a/posix/Makefile b/posix/Makefile
index 4507d84bf1..16c5111df1 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -101,7 +101,8 @@ tests := test-errno tstgetopt testfnm runtests runptests \
tst-sysconf-empty-chroot tst-glob_symlinks tst-fexecve \
tst-glob-tilde test-ssize-max tst-spawn4 bug-regex37 \
bug-regex38 tst-regcomp-truncated tst-spawn-chdir \
- tst-wordexp-nocmd
+ tst-wordexp-nocmd tst-wordexp-reuse
+
tests-internal := bug-regex5 bug-regex20 bug-regex33 \
tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3 \
tst-glob_lstat_compat tst-spawn4-compat
@@ -134,11 +135,13 @@ generated += $(addprefix wordexp-test-result, 1 2 3 4 5 6 7 8 9 10) \
bug-glob2.mtrace bug-glob2-mem.out tst-vfork3-mem.out \
tst-vfork3.mtrace getconf.speclist tst-fnmatch-mem.out \
tst-fnmatch.mtrace bug-regex36.mtrace \
- testcases.h ptestcases.h
+ testcases.h ptestcases.h tst-wordexp-reuse-mem.out \
+ tst-wordexp-reuse.mtrace
ifeq ($(run-built-tests),yes)
ifeq (yes,$(build-shared))
-tests-special += $(objpfx)globtest.out $(objpfx)wordexp-tst.out
+tests-special += $(objpfx)globtest.out $(objpfx)wordexp-tst.out \
+ $(objpfx)wordexp-tst.out
endif
endif
@@ -152,7 +155,7 @@ tests-special += $(objpfx)bug-regex2-mem.out $(objpfx)bug-regex14-mem.out \
$(objpfx)tst-boost-mem.out $(objpfx)tst-getconf.out \
$(objpfx)bug-glob2-mem.out $(objpfx)tst-vfork3-mem.out \
$(objpfx)tst-fnmatch-mem.out $(objpfx)bug-regex36-mem.out \
- $(objpfx)tst-glob-tilde-mem.out
+ $(objpfx)tst-glob-tilde-mem.out $(objpfx)tst-wordexp-reuse.out
xtests-special += $(objpfx)bug-ga2-mem.out
endif
@@ -397,3 +400,9 @@ $(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
+
+$(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 56289503a1..866603b1ed 100644
--- a/posix/wordexp.c
+++ b/posix/wordexp.c
@@ -2220,7 +2220,9 @@ 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)
--
2.53.0
