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[PATCH v4] libio: do not attempt to free wide buffers of legacy streams [BZ #24228]
Commit a601b74d31ca086de38441d316a3dee24c866305 aka glibc-2.23~693
("In preparation for fixing BZ#16734, fix failure in misc/tst-error1-mem
when _G_HAVE_MMAP is turned off.") introduced a regression:
_IO_unbuffer_all() now invokes _IO_wsetb() to free wide buffers of all
files, including legacy standard files which are small statically
allocated objects that do not have wide buffers and the _mode member,
causing memory corruption.
Another memory corruption in _IO_unbuffer_all() happens when -1
is assigned to the _mode member of legacy standard files that do not
have it.
[BZ #24228]
* libio/genops.c (_IO_unbuffer_all)
[SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)]: Do not attempt to free wide
buffers and access _IO_FILE_complete members of legacy libio streams.
* libio/tst-bz24228.c: New file.
* libio/tst-bz24228.map: Likewise.
* libio/Makefile (tests): Add tst-bz24228.
(generated): Add tst-bz24228.mtrace and tst-bz24228.check.
(tests-special): Add $(objpfx)tst-bz24228-mem.out.
(LDFLAGS-tst-bz24228, tst-bz24228-ENV): New variables.
($(objpfx)tst-bz24228-mem.out): New rule.
---
ChangeLog | 14 ++++++++++++++
libio/Makefile | 11 ++++++++++-
libio/genops.c | 16 ++++++++++++----
libio/tst-bz24228.c | 29 +++++++++++++++++++++++++++++
libio/tst-bz24228.map | 5 +++++
5 files changed, 70 insertions(+), 5 deletions(-)
create mode 100644 libio/tst-bz24228.c
create mode 100644 libio/tst-bz24228.map
diff --git a/libio/Makefile b/libio/Makefile
index 7d53cb06b0..b81e8bf5e2 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -65,7 +65,7 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \
tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos tst-fseek \
tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \
tst-ftell-append tst-fputws tst-bz22415 tst-fgetc-after-eof \
- tst-sprintf-ub tst-sprintf-chk-ub tst-bz24051 tst-bz24153 \
+ tst-sprintf-ub tst-sprintf-chk-ub tst-bz24051 tst-bz24153 tst-bz24228 \
tst-wfile-sync tst-wfile-gconv
# This test tests interaction with the gconv cache. Setting
@@ -162,16 +162,20 @@ CFLAGS-tst_putwc.c += -DOBJPFX=\"$(objpfx)\"
CFLAGS-tst-sprintf-ub.c += -Wno-restrict
CFLAGS-tst-sprintf-chk-ub.c += -Wno-restrict
+LDFLAGS-tst-bz24228 = -Wl,--version-script=tst-bz24228.map
+
tst_wprintf2-ARGS = "Some Text"
test-fmemopen-ENV = MALLOC_TRACE=$(objpfx)test-fmemopen.mtrace
tst-fopenloc-ENV = MALLOC_TRACE=$(objpfx)tst-fopenloc.mtrace
tst-bz22415-ENV = MALLOC_TRACE=$(objpfx)tst-bz22415.mtrace
+tst-bz24228-ENV = MALLOC_TRACE=$(objpfx)tst-bz24228.mtrace
tst-wfile-gconv-ENV = MALLOC_TRACE=$(objpfx)tst-wfile-gconv.mtrace
generated += test-fmemopen.mtrace test-fmemopen.check
generated += tst-fopenloc.mtrace tst-fopenloc.check
generated += tst-bz22415.mtrace tst-bz22415.check
+generated += tst-bz24228.mtrace tst-bz24228.check
generated += tst-wfile-gconv.mtrace tst-wfile-gconv.check
aux := fileops genops stdfiles stdio strops
@@ -188,6 +192,7 @@ shared-only-routines = oldiofopen oldiofdopen oldiofclose oldfileops \
ifeq ($(run-built-tests),yes)
tests-special += $(objpfx)test-freopen.out $(objpfx)test-fmemopen-mem.out \
$(objpfx)tst-bz22415-mem.out \
+ $(objpfx)tst-bz24228-mem.out \
$(objpfx)tst-wfile-gconv-mem.out
ifeq (yes,$(build-shared))
# Run tst-fopenloc-cmp.out and tst-openloc-mem.out only if shared
@@ -246,6 +251,10 @@ $(objpfx)tst-bz22415-mem.out: $(objpfx)tst-bz22415.out
$(common-objpfx)malloc/mtrace $(objpfx)tst-bz22415.mtrace > $@; \
$(evaluate-test)
+$(objpfx)tst-bz24228-mem.out: $(objpfx)tst-bz24228.out
+ $(common-objpfx)malloc/mtrace $(objpfx)tst-bz24228.mtrace > $@; \
+ $(evaluate-test)
+
$(objpfx)tst-wfile-gconv-mem.out: $(objpfx)tst-wfile-gconv.out
$(common-objpfx)malloc/mtrace $(objpfx)tst-wfile-gconv.mtrace > $@; \
$(evaluate-test)
diff --git a/libio/genops.c b/libio/genops.c
index 2a0d9b81df..11a15549e8 100644
--- a/libio/genops.c
+++ b/libio/genops.c
@@ -789,9 +789,16 @@ _IO_unbuffer_all (void)
for (fp = (FILE *) _IO_list_all; fp; fp = fp->_chain)
{
+ int legacy = 0;
+
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
+ if (__glibc_unlikely (_IO_vtable_offset (fp) != 0))
+ legacy = 1;
+#endif
+
if (! (fp->_flags & _IO_UNBUFFERED)
/* Iff stream is un-orientated, it wasn't used. */
- && fp->_mode != 0)
+ && (legacy || fp->_mode != 0))
{
#ifdef _IO_MTSAFE_IO
int cnt;
@@ -805,7 +812,7 @@ _IO_unbuffer_all (void)
__sched_yield ();
#endif
- if (! dealloc_buffers && !(fp->_flags & _IO_USER_BUF))
+ if (! legacy && ! dealloc_buffers && !(fp->_flags & _IO_USER_BUF))
{
fp->_flags |= _IO_USER_BUF;
@@ -816,7 +823,7 @@ _IO_unbuffer_all (void)
_IO_SETBUF (fp, NULL, 0);
- if (fp->_mode > 0)
+ if (! legacy && fp->_mode > 0)
_IO_wsetb (fp, NULL, NULL, 0);
#ifdef _IO_MTSAFE_IO
@@ -827,7 +834,8 @@ _IO_unbuffer_all (void)
/* Make sure that never again the wide char functions can be
used. */
- fp->_mode = -1;
+ if (! legacy)
+ fp->_mode = -1;
}
#ifdef _IO_MTSAFE_IO
diff --git a/libio/tst-bz24228.c b/libio/tst-bz24228.c
new file mode 100644
index 0000000000..6a74500d47
--- /dev/null
+++ b/libio/tst-bz24228.c
@@ -0,0 +1,29 @@
+/* BZ #24228 check for memory corruption in legacy libio
+ Copyright (C) 2019 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 <support/test-driver.h>
+
+static int
+do_test (void)
+{
+ mtrace ();
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/libio/tst-bz24228.map b/libio/tst-bz24228.map
new file mode 100644
index 0000000000..4383e0817d
--- /dev/null
+++ b/libio/tst-bz24228.map
@@ -0,0 +1,5 @@
+# Hide the symbol from libc.so.6 to switch to the libio/oldfileops.c
+# implementation when it is available for the architecture.
+{
+ local: _IO_stdin_used;
+};
--
ldv