Add test program for decryption of overly short buffers

Pull up r23652 from trunk.

Test case for integer underflow in AES and RC4 decryption.
[MITKRB5-SA-2009-004, CVE-2009-4212] krb5-1.8 branch isn't vulnerable,
but include this test anyway.

 ------------------------------------------------------------------------
 r23652 | ghudson | 2010-01-12 16:59:58 -0500 (Tue, 12 Jan 2010) | 2 lines

 Add test program for decryption of overly short buffers.

ticket: 6642
target_version: 1.8
version_fixed: 1.8
tags: pullup
status: resolved

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-8@23660 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/crypto/crypto_tests/Makefile.in b/src/lib/crypto/crypto_tests/Makefile.in
index fde5a73c48b83cdf1686e84e95329da4c5121c8f..c92cc7e8d4bbfaebcfb88ebf6fe00607df6851d4 100644 (file)
--- a/src/lib/crypto/crypto_tests/Makefile.in
+++ b/src/lib/crypto/crypto_tests/Makefile.in
@@ -27,6 +27,7 @@ EXTRADEPSRCS=\
        $(srcdir)/t_crc.c       \
        $(srcdir)/t_mddriver.c  \
        $(srcdir)/t_kperf.c     \
+       $(srcdir)/t_short.c     \
        $(srcdir)/ytest.c       
 
 ##DOSBUILDTOP = ..\..\..
@@ -44,7 +45,7 @@ check-unix:: t_nfold t_encrypt t_prf t_prng t_hmac \
                t_cksum4 t_cksum5 \
                aes-test  \
                t_mddriver4 t_mddriver \
-               t_crc t_cts
+               t_crc t_cts t_short
        $(RUN_SETUP) $(VALGRIND) ./t_nfold
        $(RUN_SETUP) $(VALGRIND) ./t_encrypt
        $(RUN_SETUP) $(VALGRIND) ./t_prng <$(srcdir)/t_prng.seed >t_prng.output && \
@@ -62,6 +63,7 @@ check-unix:: t_nfold t_encrypt t_prf t_prng t_hmac \
        cmp vt.txt $(srcdir)/expect-vt.txt
        $(RUN_SETUP) $(VALGRIND) $(C)t_mddriver4 -x
        $(RUN_SETUP) $(VALGRIND) $(C)t_mddriver -x
+       $(RUN_SETUP) $(VALGRIND) ./t_short
 
 
 
@@ -96,6 +98,10 @@ vectors$(EXEEXT): vectors.$(OBJEXT) $(CRYPTO_DEPLIB) $(SUPPORT_DEPLIB)
        $(CC_LINK) -o $@ t_cts.$(OBJEXT) \
                $(K5CRYPTO_LIB) $(COM_ERR_LIB) $(SUPPORT_LIB)
 
+t_short$(EXEEXT): t_short.$(OBJEXT) $(CRYPTO_DEPLIB) $(SUPPORT_DEPLIB)
+       $(CC_LINK) -o $@ t_short.$(OBJEXT) \
+               $(K5CRYPTO_LIB) $(COM_ERR_LIB) $(SUPPORT_LIB)
+
 t_cksum4.o: $(srcdir)/t_cksum.c
        $(CC) -DMD=4 $(ALL_CFLAGS) -o t_cksum4.o -c $(srcdir)/t_cksum.c
 
@@ -139,7 +145,8 @@ clean::
                t_cksum.o t_cksum \
                t_crc.o t_crc t_cts.o t_cts \
                t_mddriver4.o t_mddriver4 t_mddriver.o t_mddriver \
-               t_cksum4 t_cksum4.o t_cksum5 t_cksum5.o t_kperf.o t_kperf \
+               t_cksum4 t_cksum4.o t_cksum5 t_cksum5.o \
+               t_kperf.o t_kperf t_short t_short.o \
                t_mddriver$(EXEEXT) $(OUTPRE)t_mddriver.$(OBJEXT)
 
        -$(RM) t_prng.output

diff --git a/src/lib/crypto/crypto_tests/t_short.c b/src/lib/crypto/crypto_tests/t_short.c
new file mode 100644 (file)
index 0000000..9ddfd5e
--- /dev/null
+++ b/src/lib/crypto/crypto_tests/t_short.c
@@ -0,0 +1,126 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+ * lib/crypto/crypto_tests/t_short.c
+ *
+ * Copyright (C) 2009 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Export of this software from the United States of America may
+ *   require a specific license from the United States Government.
+ *   It is the responsibility of any person or organization contemplating
+ *   export to obtain such a license before exporting.
+ *
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission.  Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ *
+ * Tests the outcome of decrypting overly short tokens.  This program can be
+ * run under a tool like valgrind to detect bad memory accesses; when run
+ * normally by the test suite, it verifies that each operation returns
+ * KRB5_BAD_MSIZE.
+ */
+
+#include "k5-int.h"
+
+krb5_enctype interesting_enctypes[] = {
+    ENCTYPE_DES_CBC_CRC,
+    ENCTYPE_DES_CBC_MD4,
+    ENCTYPE_DES_CBC_MD5,
+    ENCTYPE_DES3_CBC_SHA1,
+    ENCTYPE_ARCFOUR_HMAC,
+    ENCTYPE_ARCFOUR_HMAC_EXP,
+    ENCTYPE_AES256_CTS_HMAC_SHA1_96,
+    ENCTYPE_AES128_CTS_HMAC_SHA1_96,
+    0
+};
+
+/* Abort if an operation unexpectedly fails. */
+static void
+x(krb5_error_code code)
+{
+    if (code != 0)
+        abort();
+}
+
+/* Abort if a decrypt operation doesn't have the expected result. */
+static void
+check_decrypt_result(krb5_error_code code, size_t len, size_t min_len)
+{
+    if (len < min_len) {
+        /* Undersized tokens should always result in BAD_MSIZE. */
+        if (code != KRB5_BAD_MSIZE)
+            abort();
+    } else {
+        /* Min-size tokens should succeed or fail the integrity check. */
+        if (code != 0 && code != KRB5KRB_AP_ERR_BAD_INTEGRITY)
+            abort();
+    }
+}
+
+static void
+test_enctype(krb5_enctype enctype)
+{
+    krb5_error_code ret;
+    krb5_keyblock keyblock;
+    krb5_enc_data input;
+    krb5_data output;
+    krb5_crypto_iov iov[2];
+    unsigned int dummy;
+    size_t min_len, len;
+
+    printf("Testing enctype %d\n", (int) enctype);
+    x(krb5_c_encrypt_length(NULL, enctype, 0, &min_len));
+    x(krb5_c_make_random_key(NULL, enctype, &keyblock));
+    input.enctype = enctype;
+
+    /* Try each length up to the minimum length. */
+    for (len = 0; len <= min_len; len++) {
+        input.ciphertext.data = calloc(len, 1);
+        input.ciphertext.length = len;
+        output.data = calloc(len, 1);
+        output.length = len;
+
+        /* Attempt a normal decryption. */
+        ret = krb5_c_decrypt(NULL, &keyblock, 0, NULL, &input, &output);
+        check_decrypt_result(ret, len, min_len);
+
+        if (krb5_c_crypto_length(NULL, enctype, KRB5_CRYPTO_TYPE_HEADER,
+                                 &dummy) == 0) {
+            /* Attempt an IOV stream decryption. */
+            iov[0].flags = KRB5_CRYPTO_TYPE_STREAM;
+            iov[0].data = input.ciphertext;
+            iov[1].flags = KRB5_CRYPTO_TYPE_DATA;
+            iov[1].data.data = NULL;
+            iov[1].data.length = 0;
+            ret = krb5_c_decrypt_iov(NULL, &keyblock, 0, NULL, iov, 2);
+            check_decrypt_result(ret, len, min_len);
+        }
+
+        free(input.ciphertext.data);
+        free(output.data);
+    }
+}
+
+int
+main(int argc, char **argv)
+{
+    int i;
+    krb5_data notrandom;
+
+    notrandom.data = "notrandom";
+    notrandom.length = 9;
+    krb5_c_random_seed(NULL, &notrandom);
+    for (i = 0; interesting_enctypes[i]; i++)
+        test_enctype(interesting_enctypes[i]);
+    return 0;
+}