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authorFlorian Weimer <fweimer@redhat.com>2015-10-02 11:34:13 +0200
committerFlorian Weimer <fweimer@redhat.com>2015-10-02 11:34:13 +0200
commit676599b36a92f3c201c5682ee7a5caddd9f370a4 (patch)
tree6860752c26ccab76ee9db5e60ff465d1edf25feb /nss/tst-field.c
parentb0f81637d5bda47be93bac34b68f429a12979321 (diff)
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Harden putpwent, putgrent, putspent, putspent against injection [BZ #18724]
This prevents injection of ':' and '\n' into output functions which use the NSS files database syntax. Critical fields (user/group names and file system paths) are checked strictly. For backwards compatibility, the GECOS field is rewritten instead. The getent program is adjusted to use the put*ent functions in libc, instead of local copies. This changes the behavior of getent if user names start with '-' or '+'.
Diffstat (limited to 'nss/tst-field.c')
-rw-r--r--nss/tst-field.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/nss/tst-field.c b/nss/tst-field.c
new file mode 100644
index 0000000000..f97d3aed9b
--- /dev/null
+++ b/nss/tst-field.c
@@ -0,0 +1,101 @@
+/* Test for invalid field handling in file-style NSS databases. [BZ #18724]
+ Copyright (C) 2015 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/>. */
+
+/* This test needs to be statically linked because it access hidden
+ functions. */
+
+#include <nss.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static bool errors;
+
+static void
+check (const char *what, bool expr)
+{
+ if (!expr)
+ {
+ printf ("FAIL: %s\n", what);
+ errors = true;
+ }
+}
+
+#define CHECK(expr) check (#expr, (expr))
+
+static void
+check_rewrite (const char *input, const char *expected)
+{
+ char *to_free;
+ const char *result = __nss_rewrite_field (input, &to_free);
+ CHECK (result != NULL);
+ if (result != NULL && strcmp (result, expected) != 0)
+ {
+ printf ("FAIL: rewrite \"%s\" -> \"%s\", expected \"%s\"\n",
+ input, result, expected);
+ errors = true;
+ }
+ free (to_free);
+}
+
+static int
+do_test (void)
+{
+ CHECK (__nss_valid_field (NULL));
+ CHECK (__nss_valid_field (""));
+ CHECK (__nss_valid_field ("+"));
+ CHECK (__nss_valid_field ("-"));
+ CHECK (__nss_valid_field (" "));
+ CHECK (__nss_valid_field ("abcdef"));
+ CHECK (__nss_valid_field ("abc def"));
+ CHECK (__nss_valid_field ("abc\tdef"));
+ CHECK (!__nss_valid_field ("abcdef:"));
+ CHECK (!__nss_valid_field ("abcde:f"));
+ CHECK (!__nss_valid_field (":abcdef"));
+ CHECK (!__nss_valid_field ("abcdef\n"));
+ CHECK (!__nss_valid_field ("\nabcdef"));
+ CHECK (!__nss_valid_field (":"));
+ CHECK (!__nss_valid_field ("\n"));
+
+ CHECK (__nss_valid_list_field (NULL));
+ CHECK (__nss_valid_list_field ((char *[]) {(char *) "good", NULL}));
+ CHECK (!__nss_valid_list_field ((char *[]) {(char *) "g,ood", NULL}));
+ CHECK (!__nss_valid_list_field ((char *[]) {(char *) "g\nood", NULL}));
+ CHECK (!__nss_valid_list_field ((char *[]) {(char *) "g:ood", NULL}));
+
+ check_rewrite (NULL, "");
+ check_rewrite ("", "");
+ check_rewrite ("abc", "abc");
+ check_rewrite ("abc\n", "abc ");
+ check_rewrite ("abc:", "abc ");
+ check_rewrite ("\nabc", " abc");
+ check_rewrite (":abc", " abc");
+ check_rewrite (":", " ");
+ check_rewrite ("\n", " ");
+ check_rewrite ("a:b:c", "a b c");
+ check_rewrite ("a\nb\nc", "a b c");
+ check_rewrite ("a\nb:c", "a b c");
+ check_rewrite ("aa\nbb\ncc", "aa bb cc");
+ check_rewrite ("aa\nbb:cc", "aa bb cc");
+
+ return errors;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"