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authorDJ Delorie <dj@redhat.com>2019-06-28 18:30:00 -0500
committerDJ Delorie <dj@redhat.com>2019-07-10 14:51:18 -0400
commit99135114ba23c3110b7e4e650fabdc5e639746b7 (patch)
tree09e4349308db59321eddff440eadaa630f60575b
parent30ba0375464f34e4bf8129f3d3dc14d0c09add17 (diff)
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nss_db: fix endent wrt NULL mappings [BZ #24695] [BZ #24696]
nss_db allows for getpwent et al to be called without a set*ent, but it only works once. After the last get*ent a set*ent is required to restart, because the end*ent did not properly reset the module. Resetting it to NULL allows for a proper restart. If the database doesn't exist, however, end*ent erroniously called munmap which set errno. The test case runs "makedb" inside the testroot, so needs selinux DSOs installed.
-rw-r--r--ChangeLog16
-rw-r--r--nss/Makefile4
-rw-r--r--nss/nss_db/db-open.c6
-rw-r--r--nss/tst-nss-db-endgrent.c54
-rw-r--r--nss/tst-nss-db-endgrent.root/etc/nsswitch.conf1
-rw-r--r--nss/tst-nss-db-endpwent.c66
-rw-r--r--nss/tst-nss-db-endpwent.root/etc/nsswitch.conf1
-rw-r--r--nss/tst-nss-db-endpwent.root/var/db/passwd.in4
-rw-r--r--support/Makefile5
-rw-r--r--support/links-dso-program-c.c17
-rw-r--r--support/links-dso-program.cc17
11 files changed, 189 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index dd99d98..d42f4fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2019-07-10 DJ Delorie <dj@redhat.com>
+ Sergei Trofimovich <slyfox@inbox.ru>
+
+ [BZ #24696]
+ [BZ #24695]
+ * nss/nss_db/db-open.c (internal_endent): Protect against NULL
+ mappings.
+ * nss/tst-nss-db-endgrent.c: New.
+ * nss/tst-nss-db-endgrent.root: New.
+ * nss/tst-nss-db-endpwent.c: New.
+ * nss/tst-nss-db-endpwent.root: New.
+ * nss/Makefile: Add new tests.
+ * support/links-dso-program-c.c: Add selinux dependency.
+ * support/links-dso-program.cc: Add selinux dependency.
+ * support/Makefile: Build those with -lselinux if enabled.
+
2019-07-10 Szabolcs Nagy <szabolcs.nagy@arm.com>
* sysdeps/aarch64/dl-machine.h (elf_machine_runtime_setup): Remove the
diff --git a/nss/Makefile b/nss/Makefile
index 95081bd..a15c3b7 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -61,7 +61,9 @@ xtests = bug-erange
tests-container = \
tst-nss-test3 \
- tst-nss-files-hosts-long
+ tst-nss-files-hosts-long \
+ tst-nss-db-endpwent \
+ tst-nss-db-endgrent
# Tests which need libdl
ifeq (yes,$(build-shared))
diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c
index 8a83d6b..3fa11e9 100644
--- a/nss/nss_db/db-open.c
+++ b/nss/nss_db/db-open.c
@@ -63,5 +63,9 @@ internal_setent (const char *file, struct nss_db_map *mapping)
void
internal_endent (struct nss_db_map *mapping)
{
- munmap (mapping->header, mapping->len);
+ if (mapping->header != NULL)
+ {
+ munmap (mapping->header, mapping->len);
+ mapping->header = NULL;
+ }
}
diff --git a/nss/tst-nss-db-endgrent.c b/nss/tst-nss-db-endgrent.c
new file mode 100644
index 0000000..367cc6c
--- /dev/null
+++ b/nss/tst-nss-db-endgrent.c
@@ -0,0 +1,54 @@
+/* Test for endgrent changing errno for BZ #24696
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdlib.h>
+#include <sys/types.h>
+#include <grp.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <support/check.h>
+#include <support/support.h>
+
+/* The following test verifies that if the db NSS Service is initialized
+ with no database (getgrent), that a subsequent closure (endgrent) does
+ not set errno. In the case of the db service it is not an error to close
+ the service and so it should not set errno. */
+
+static int
+do_test (void)
+{
+ /* Just make sure it's not there, although usually it won't be. */
+ unlink ("/var/db/group.db");
+
+ /* This, in conjunction with the testroot's nsswitch.conf, causes
+ the nss_db module to be "connected" and initialized - but the
+ testroot has no group.db, so no mapping will be created. */
+ getgrent ();
+
+ errno = 0;
+
+ /* Before the fix, this would call munmap (NULL) and set errno. */
+ endgrent ();
+
+ if (errno != 0)
+ FAIL_EXIT1 ("endgrent set errno to %d\n", errno);
+
+ return 0;
+}
+#include <support/test-driver.c>
diff --git a/nss/tst-nss-db-endgrent.root/etc/nsswitch.conf b/nss/tst-nss-db-endgrent.root/etc/nsswitch.conf
new file mode 100644
index 0000000..21471df
--- /dev/null
+++ b/nss/tst-nss-db-endgrent.root/etc/nsswitch.conf
@@ -0,0 +1 @@
+group : db files
diff --git a/nss/tst-nss-db-endpwent.c b/nss/tst-nss-db-endpwent.c
new file mode 100644
index 0000000..cb85410
--- /dev/null
+++ b/nss/tst-nss-db-endpwent.c
@@ -0,0 +1,66 @@
+/* Test for endpwent->getpwent crash for BZ #24695
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <pwd.h>
+
+#include <support/support.h>
+#include <support/check.h>
+
+/* It is entirely allowed to start with a getpwent call without
+ resetting the state of the service via a call to setpwent.
+ You can also call getpwent more times than you have entries in
+ the service, and it should not fail. This test iteratates the
+ database once, gets to the end, and then attempts a second
+ iteration to look for crashes. */
+
+static void
+try_it (void)
+{
+ struct passwd *pw;
+
+ /* setpwent is intentionally omitted here. The first call to
+ getpwent detects that it's first and initializes. The second
+ time try_it is called, this "first call" was not detected before
+ the fix, and getpwent would crash. */
+
+ while ((pw = getpwent ()) != NULL)
+ ;
+
+ /* We only care if this segfaults or not. */
+ endpwent ();
+}
+
+static int
+do_test (void)
+{
+ char *cmd;
+
+ cmd = xasprintf ("%s/makedb -o /var/db/passwd.db /var/db/passwd.in",
+ support_bindir_prefix);
+ system (cmd);
+ free (cmd);
+
+ try_it ();
+ try_it ();
+
+ return 0;
+}
+#include <support/test-driver.c>
diff --git a/nss/tst-nss-db-endpwent.root/etc/nsswitch.conf b/nss/tst-nss-db-endpwent.root/etc/nsswitch.conf
new file mode 100644
index 0000000..593ffc5
--- /dev/null
+++ b/nss/tst-nss-db-endpwent.root/etc/nsswitch.conf
@@ -0,0 +1 @@
+passwd: db
diff --git a/nss/tst-nss-db-endpwent.root/var/db/passwd.in b/nss/tst-nss-db-endpwent.root/var/db/passwd.in
new file mode 100644
index 0000000..98f3912
--- /dev/null
+++ b/nss/tst-nss-db-endpwent.root/var/db/passwd.in
@@ -0,0 +1,4 @@
+.root root:x:0:0:root:/root:/bin/bash
+=0 root:x:0:0:root:/root:/bin/bash
+.bin bin:x:1:1:bin:/bin:/sbin/nologin
+=1 bin:x:1:1:bin:/bin:/sbin/nologin
diff --git a/support/Makefile b/support/Makefile
index 56c1ed4..ab66913 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -191,6 +191,11 @@ LINKS_DSO_PROGRAM = links-dso-program
LDLIBS-links-dso-program = -lstdc++ -lgcc -lgcc_s $(libunwind)
endif
+ifeq (yes,$(have-selinux))
+LDLIBS-$(LINKS_DSO_PROGRAM) += -lselinux
+endif
+
+
LDLIBS-test-container = $(libsupport)
others += test-container
diff --git a/support/links-dso-program-c.c b/support/links-dso-program-c.c
index d28a28a..5fcbab2 100644
--- a/support/links-dso-program-c.c
+++ b/support/links-dso-program-c.c
@@ -1,9 +1,26 @@
#include <stdio.h>
+/* makedb needs selinux dso's. */
+#ifdef HAVE_SELINUX
+# include <selinux/selinux.h>
+#endif
+
+/* The purpose of this file is to indicate to the build system which
+ shared objects need to be copied into the testroot, such as gcc or
+ selinux support libraries. This program is never executed, only
+ scanned for dependencies on shared objects, so the code below may
+ seem weird - it's written to survive gcc optimization and force
+ such dependencies.
+*/
+
int
main (int argc, char **argv)
{
/* Complexity to keep gcc from optimizing this away. */
printf ("This is a test %s.\n", argc > 1 ? argv[1] : "null");
+#ifdef HAVE_SELINUX
+ /* This exists to force libselinux.so to be required. */
+ printf ("selinux %d\n", is_selinux_enabled ());
+#endif
return 0;
}
diff --git a/support/links-dso-program.cc b/support/links-dso-program.cc
index dba6976..4bc2411 100644
--- a/support/links-dso-program.cc
+++ b/support/links-dso-program.cc
@@ -1,11 +1,28 @@
#include <iostream>
+/* makedb needs selinux dso's. */
+#ifdef HAVE_SELINUX
+# include <selinux/selinux.h>
+#endif
+
using namespace std;
+/* The purpose of this file is to indicate to the build system which
+ shared objects need to be copied into the testroot, such as gcc or
+ selinux support libraries. This program is never executed, only
+ scanned for dependencies on shared objects, so the code below may
+ seem weird - it's written to survive gcc optimization and force
+ such dependencies.
+*/
+
int
main (int argc, char **argv)
{
/* Complexity to keep gcc from optimizing this away. */
cout << (argc > 1 ? argv[1] : "null");
+#ifdef HAVE_SELINUX
+ /* This exists to force libselinux.so to be required. */
+ cout << "selinux " << is_selinux_enabled ();
+#endif
return 0;
}