This is the mail archive of the
elfutils-devel@sourceware.org
mailing list for the elfutils project.
[PATCH] ar: Check whether ar header values fit.
- From: Mark Wielaard <mark at klomp dot org>
- To: elfutils-devel at sourceware dot org
- Cc: Matthias Klose <doko at ubuntu dot com>, Mark Wielaard <mark at klomp dot org>
- Date: Fri, 15 Sep 2017 13:14:36 +0200
- Subject: [PATCH] ar: Check whether ar header values fit.
- Authentication-results: sourceware.org; auth=none
When compiling with -O3 gcc finds an interesting error:
src/ar.c: In function ‘do_oper_insert’:
src/ar.c:1077:56: error: ‘%-*ld’ directive output may be truncated writing between 6 and 10 bytes into a region of size 7 [-Werror=format-truncation=]
snprintf (tmpbuf, sizeof (tmpbuf), ofmt ? "%-*lo" : "%-*ld", bufsize, val);
^~~~~
The problem is that the ar header values have to fit in a limited
(not zero terminated) string. We should check the snprintf return
value to see if the values are representable.
Also make ar valgrind and ubsan clean and add a minimal sanity test.
Reported-by: Matthias Klose <doko@ubuntu.com>
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
src/ChangeLog | 9 ++++++++
src/ar.c | 66 ++++++++++++++++++++++++++++++++++++++-----------------
tests/ChangeLog | 6 +++++
tests/Makefile.am | 4 ++--
tests/run-ar.sh | 40 +++++++++++++++++++++++++++++++++
5 files changed, 103 insertions(+), 22 deletions(-)
create mode 100755 tests/run-ar.sh
diff --git a/src/ChangeLog b/src/ChangeLog
index daedfca..3c34026 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2017-09-10 Mark Wielaard <mark@klomp.org>
+
+ * ar.c (do_oper_delete): Remove DEBUG conditional check.
+ (no0print): Return bool. Check snprintf return value.
+ (do_oper_insert): Initialize elf. Remove DEBUG conditional check.
+ Check no0print calls succeed. Explicitly elf_end found elfs.
+ (do_oper_extract): Make sure we don't create an empty variable
+ length array.
+
2017-05-04 Ulf Hermann <ulf.hermann@qt.io>
* stack.c: Print pid_t using %lld.
diff --git a/src/ar.c b/src/ar.c
index ec32cee..818115b 100644
--- a/src/ar.c
+++ b/src/ar.c
@@ -1,5 +1,5 @@
/* Create, modify, and extract from archives.
- Copyright (C) 2005-2012, 2016 Red Hat, Inc.
+ Copyright (C) 2005-2012, 2016, 2017 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 2005.
@@ -442,7 +442,7 @@ static int
do_oper_extract (int oper, const char *arfname, char **argv, int argc,
long int instance)
{
- bool found[argc];
+ bool found[argc > 0 ? argc : 1];
memset (found, '\0', sizeof (found));
size_t name_max = 0;
@@ -1056,13 +1056,11 @@ do_oper_delete (const char *arfname, char **argv, int argc,
goto nonew_unlink;
errout:
-#ifdef DEBUG
elf_end (elf);
arlib_fini ();
close (fd);
-#endif
not_found (argc, argv, found);
@@ -1070,12 +1068,18 @@ do_oper_delete (const char *arfname, char **argv, int argc,
}
-static void
+/* Prints the given value in the given buffer without a trailing zero char.
+ Returns false if the given value doesn't fit in the given buffer. */
+static bool
no0print (bool ofmt, char *buf, int bufsize, long int val)
{
char tmpbuf[bufsize + 1];
- snprintf (tmpbuf, sizeof (tmpbuf), ofmt ? "%-*lo" : "%-*ld", bufsize, val);
+ int ret = snprintf (tmpbuf, sizeof (tmpbuf), ofmt ? "%-*lo" : "%-*ld",
+ bufsize, val);
+ if (ret >= (int) sizeof (tmpbuf))
+ return false;
memcpy (buf, tmpbuf, bufsize);
+ return true;
}
@@ -1084,7 +1088,7 @@ do_oper_insert (int oper, const char *arfname, char **argv, int argc,
const char *member)
{
int status = 0;
- Elf *elf;
+ Elf *elf = NULL;
struct stat st;
int fd = open_archive (arfname, O_RDONLY, 0, &elf, &st, oper != oper_move);
@@ -1303,13 +1307,11 @@ do_oper_insert (int oper, const char *arfname, char **argv, int argc,
if (status != 0)
{
-#ifdef DEBUG
elf_end (elf);
arlib_fini ();
close (fd);
-#endif
return status;
}
@@ -1463,14 +1465,36 @@ do_oper_insert (int oper, const char *arfname, char **argv, int argc,
memcpy (arhdr.ar_name, tmpbuf, sizeof (arhdr.ar_name));
}
- no0print (false, arhdr.ar_date, sizeof (arhdr.ar_date),
- all->sec);
- no0print (false, arhdr.ar_uid, sizeof (arhdr.ar_uid), all->uid);
- no0print (false, arhdr.ar_gid, sizeof (arhdr.ar_gid), all->gid);
- no0print (true, arhdr.ar_mode, sizeof (arhdr.ar_mode),
- all->mode);
- no0print (false, arhdr.ar_size, sizeof (arhdr.ar_size),
- all->size);
+ if (! no0print (false, arhdr.ar_date, sizeof (arhdr.ar_date),
+ all->sec))
+ {
+ error (0, errno, gettext ("cannot represent ar_date"));
+ goto nonew_unlink;
+ }
+ if (! no0print (false, arhdr.ar_uid, sizeof (arhdr.ar_uid),
+ all->uid))
+ {
+ error (0, errno, gettext ("cannot represent ar_uid"));
+ goto nonew_unlink;
+ }
+ if (! no0print (false, arhdr.ar_gid, sizeof (arhdr.ar_gid),
+ all->gid))
+ {
+ error (0, errno, gettext ("cannot represent ar_gid"));
+ goto nonew_unlink;
+ }
+ if (! no0print (true, arhdr.ar_mode, sizeof (arhdr.ar_mode),
+ all->mode))
+ {
+ error (0, errno, gettext ("cannot represent ar_mode"));
+ goto nonew_unlink;
+ }
+ if (! no0print (false, arhdr.ar_size, sizeof (arhdr.ar_size),
+ all->size))
+ {
+ error (0, errno, gettext ("cannot represent ar_size"));
+ goto nonew_unlink;
+ }
memcpy (arhdr.ar_fmag, ARFMAG, sizeof (arhdr.ar_fmag));
if (unlikely (write_retry (newfd, &arhdr, sizeof (arhdr))
@@ -1514,13 +1538,15 @@ do_oper_insert (int oper, const char *arfname, char **argv, int argc,
goto nonew_unlink;
errout:
-#ifdef DEBUG
+ for (int cnt = 0; cnt < argc; ++cnt)
+ elf_end (found[cnt]->elf);
+
elf_end (elf);
arlib_fini ();
- close (fd);
-#endif
+ if (fd != -1)
+ close (fd);
return status;
}
diff --git a/tests/ChangeLog b/tests/ChangeLog
index 0d5bee7..7b6bf30 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-10 Mark Wielaard <mark@klomp.org>
+
+ * run-ar.sh: New test.
+ * Makefile.am (TESTS): Add run-ar.sh.
+ (EXTRA_DIST): Likewise.
+
2017-08-18 Ulf Hermann <ulf.hermann@qt.io>
* Makefile.am: Drop -rdynamic from deleted_lib_so_LDFLAGS.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 2eac802..e583504 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -72,7 +72,7 @@ backtrace-child-biarch$(EXEEXT): backtrace-child.c
$(AM_LDFLAGS) $(LDFLAGS) $(backtrace_child_LDFLAGS) \
-o $@ $<
-TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \
+TESTS = run-arextract.sh run-arsymtest.sh run-ar.sh newfile test-nlist \
update1 update2 update3 update4 \
run-show-die-info.sh run-get-files.sh run-get-lines.sh \
run-get-pubnames.sh run-get-aranges.sh run-allfcts.sh \
@@ -159,7 +159,7 @@ check_PROGRAMS += $(asm_TESTS)
TESTS += $(asm_TESTS) run-disasm-bpf.sh
endif
-EXTRA_DIST = run-arextract.sh run-arsymtest.sh \
+EXTRA_DIST = run-arextract.sh run-arsymtest.sh run-ar.sh \
run-show-die-info.sh run-get-files.sh run-get-lines.sh \
run-get-pubnames.sh run-get-aranges.sh \
run-show-abbrev.sh run-strip-test.sh \
diff --git a/tests/run-ar.sh b/tests/run-ar.sh
new file mode 100755
index 0000000..fb9394d
--- /dev/null
+++ b/tests/run-ar.sh
@@ -0,0 +1,40 @@
+#! /bin/bash
+# Copyright (C) 2017 Red Hat, Inc.
+# This file is part of elfutils.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# elfutils 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+. $srcdir/test-subr.sh
+
+tempfiles objects.list test.ar
+
+echo Make a sorted list of the just build src .o files.
+(cd ${abs_top_builddir}/src; ls *.o | sort) > objects.list
+cat objects.list
+
+echo Create a new ar file with the .o files.
+testrun ${abs_top_builddir}/src/ar -r test.ar \
+ $(echo ${abs_top_builddir}/src/*.o | sort)
+
+echo List the ar file contents.
+testrun_compare ${abs_top_builddir}/src/ar -t test.ar < objects.list
+
+echo Delete all objects again.
+testrun ${abs_top_builddir}/src/ar -d test.ar $(cat objects.list)
+
+echo Check new ar file is now empty
+testrun_compare ${abs_top_builddir}/src/ar -t test.ar << EOF
+EOF
+
+exit 0
--
1.8.3.1