Bug#989678: unblock: nettle/3.7.3-1
Package: release.debian.org
Severity: normal
User: release.debian.org@packages.debian.org
Usertags: unblock
Can I get a pre-approval and unblock for nettle 3.7.3-1? This is a pure bugfix release addressing only CVE-2021-3580, possible DOS vulnerability on invalid (zero
or too large) input to RSA decryption functions.
(It also improves test coverage.)
https://security-tracker.debian.org/tracker/CVE-2021-3580
https://bugs.debian.org/989631
unblock nettle/3.7.3-1
ChangeLog | 36 +++++++++++++++++++++++
NEWS | 38 ++++++++++++++++++++++++
configure | 22 +++++++-------
configure.ac | 6 ++--
debian/changelog | 7 +++++
nettle.pdf | Bin 651264 -> 651264 bytes
pkcs1-sec-decrypt.c | 8 +++--
rsa-decrypt-tr.c | 11 ++++---
rsa-decrypt.c | 10 +++++++
rsa-internal.h | 4 +--
rsa-sec-decrypt.c | 13 +++++++--
rsa-sign-tr.c | 61 +++++++++++++++++++--------------------
rsa.h | 5 ++--
testsuite/rsa-encrypt-test.c | 40 ++++++++++++++++++++++++-
testsuite/rsa-sec-decrypt-test.c | 17 ++++++++++-
15 files changed, 216 insertions(+), 62 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index bb169e8..4787cff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,39 @@
+2021-05-22 Niels Möller <nisse@lysator.liu.se>
+
+ * configure.ac: Bump package version, to 3.7.3.
+ (LIBNETTLE_MINOR): Bump minor number, to 8.4.
+ (LIBHOGWEED_MINOR): Bump minor number, to 6.4.
+
+2021-05-17 Niels Möller <nisse@lysator.liu.se>
+
+ * rsa-decrypt-tr.c (rsa_decrypt_tr): Check up-front that input is
+ in range.
+ * rsa-sec-decrypt.c (rsa_sec_decrypt): Likewise.
+ * rsa-decrypt.c (rsa_decrypt): Likewise.
+ * testsuite/rsa-encrypt-test.c (test_main): Add tests with input > n.
+
+2021-05-14 Niels Möller <nisse@lysator.liu.se>
+
+ * rsa-sign-tr.c (rsa_sec_blind): Delete mn argument.
+ (_rsa_sec_compute_root_tr): Delete mn argument, instead require
+ that input size matches key size. Rearrange use of temporary
+ storage, to support in-place operation, x == m. Update all
+ callers.
+
+ * rsa-decrypt-tr.c (rsa_decrypt_tr): Make zero-padded copy of
+ input, for calling _rsa_sec_compute_root_tr.
+ * rsa-sec-decrypt.c (rsa_sec_decrypt): Likewise.
+
+ * testsuite/rsa-encrypt-test.c (test_main): Test calling all of
+ rsa_decrypt, rsa_decrypt_tr, and rsa_sec_decrypt with zero input.
+
+2021-05-06 Niels Möller <nisse@lysator.liu.se>
+
+ * pkcs1-sec-decrypt.c (_pkcs1_sec_decrypt): Check that message
+ length is valid, for given key size.
+ * testsuite/rsa-sec-decrypt-test.c (test_main): Add test cases for
+ calls to rsa_sec_decrypt specifying a too large message length.
+
2021-03-21 Niels Möller <nisse@lysator.liu.se>
* NEWS: NEWS entries for 3.7.2.
diff --git a/NEWS b/NEWS
index 897527c..4a55da8 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,41 @@
+NEWS for the Nettle 3.7.3 release
+
+ This is bugfix release, fixing bugs that could make the RSA
+ decryption functions crash on invalid inputs.
+
+ Upgrading to the new version is strongly recommended. For
+ applications that want to support older versions of Nettle,
+ the bug can be worked around by adding a check that the RSA
+ ciphertext is in the range 0 < ciphertext < n, before
+ attempting to decrypt it.
+
+ Thanks to Paul Schaub and Justus Winter for reporting these
+ problems.
+
+ The new version is intended to be fully source and binary
+ compatible with Nettle-3.6. The shared library names are
+ libnettle.so.8.4 and libhogweed.so.6.4, with sonames
+ libnettle.so.8 and libhogweed.so.6.
+
+ Bug fixes:
+
+ * Fix crash for zero input to rsa_sec_decrypt and
+ rsa_decrypt_tr. Potential denial of service vector.
+
+ * Ensure that all of rsa_decrypt_tr and rsa_sec_decrypt return
+ failure for out of range inputs, instead of either crashing,
+ or silently reducing input modulo n. Potential denial of
+ service vector.
+
+ * Ensure that rsa_decrypt returns failure for out of range
+ inputs, instead of silently reducing input modulo n.
+
+ * Ensure that rsa_sec_decrypt returns failure if the message
+ size is too large for the given key. Unlike the other bugs,
+ this would typically be triggered by invalid local
+ configuration, rather than by processing untrusted remote
+ data.
+
NEWS for the Nettle 3.7.2 release
This is a bugfix release, fixing a bug in ECDSA signature
diff --git a/configure b/configure
index 9dc199b..500bd92 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
#! /bin/sh
# Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for nettle 3.7.2.
+# Generated by GNU Autoconf 2.69 for nettle 3.7.3.
#
# Report bugs to <nettle-bugs@lists.lysator.liu.se>.
#
@@ -580,8 +580,8 @@ MAKEFLAGS=
# Identity of this package.
PACKAGE_NAME='nettle'
PACKAGE_TARNAME='nettle'
-PACKAGE_VERSION='3.7.2'
-PACKAGE_STRING='nettle 3.7.2'
+PACKAGE_VERSION='3.7.3'
+PACKAGE_STRING='nettle 3.7.3'
PACKAGE_BUGREPORT='nettle-bugs@lists.lysator.liu.se'
PACKAGE_URL=''
@@ -1343,7 +1343,7 @@ if test "$ac_init_help" = "long"; then
# Omit some internal or obsolete options to make the list less imposing.
# This message is too long to be a string in the A/UX 3.1 sh.
cat <<_ACEOF
-\`configure' configures nettle 3.7.2 to adapt to many kinds of systems.
+\`configure' configures nettle 3.7.3 to adapt to many kinds of systems.
Usage: $0 [OPTION]... [VAR=VALUE]...
@@ -1409,7 +1409,7 @@ fi
if test -n "$ac_init_help"; then
case $ac_init_help in
- short | recursive ) echo "Configuration of nettle 3.7.2:";;
+ short | recursive ) echo "Configuration of nettle 3.7.3:";;
esac
cat <<\_ACEOF
@@ -1531,7 +1531,7 @@ fi
test -n "$ac_init_help" && exit $ac_status
if $ac_init_version; then
cat <<\_ACEOF
-nettle configure 3.7.2
+nettle configure 3.7.3
generated by GNU Autoconf 2.69
Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2175,7 +2175,7 @@ cat >config.log <<_ACEOF
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.
-It was created by nettle $as_me 3.7.2, which was
+It was created by nettle $as_me 3.7.3, which was
generated by GNU Autoconf 2.69. Invocation command line was
$ $0 $@
@@ -2560,10 +2560,10 @@ ac_config_headers="$ac_config_headers config.h"
LIBNETTLE_MAJOR=8
-LIBNETTLE_MINOR=3
+LIBNETTLE_MINOR=4
LIBHOGWEED_MAJOR=6
-LIBHOGWEED_MINOR=3
+LIBHOGWEED_MINOR=4
MAJOR_VERSION=`echo $PACKAGE_VERSION | sed 's/^\([^.]*\)\..*/\1/'`
MINOR_VERSION=`echo $PACKAGE_VERSION | sed 's/^[^.]*\.\([0-9]*\).*/\1/'`
@@ -8142,7 +8142,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
# report actual input values of CONFIG_FILES etc. instead of their
# values after options handling.
ac_log="
-This file was extended by nettle $as_me 3.7.2, which was
+This file was extended by nettle $as_me 3.7.3, which was
generated by GNU Autoconf 2.69. Invocation command line was
CONFIG_FILES = $CONFIG_FILES
@@ -8208,7 +8208,7 @@ _ACEOF
cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
ac_cs_version="\\
-nettle config.status 3.7.2
+nettle config.status 3.7.3
configured by $0, generated by GNU Autoconf 2.69,
with options \\"\$ac_cs_config\\"
diff --git a/configure.ac b/configure.ac
index 9b2c153..f4d9e90 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@ dnl -*- mode: shell-script; sh-indentation: 2; -*-
dnl Process this file with autoconf to produce a configure script.
-AC_INIT([nettle], [3.7.2], [nettle-bugs@lists.lysator.liu.se])
+AC_INIT([nettle], [3.7.3], [nettle-bugs@lists.lysator.liu.se])
AC_PREREQ(2.61)
AC_CONFIG_SRCDIR([arcfour.c])
# Needed to stop autoconf from looking for files in parent directories.
@@ -11,10 +11,10 @@ AC_CONFIG_AUX_DIR([.])
AC_CONFIG_HEADER([config.h])
LIBNETTLE_MAJOR=8
-LIBNETTLE_MINOR=3
+LIBNETTLE_MINOR=4
LIBHOGWEED_MAJOR=6
-LIBHOGWEED_MINOR=3
+LIBHOGWEED_MINOR=4
dnl Note double square brackets, for extra m4 quoting.
MAJOR_VERSION=`echo $PACKAGE_VERSION | sed 's/^\([[^.]]*\)\..*/\1/'`
diff --git a/debian/changelog b/debian/changelog
index 37928ba..b1820ea 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+nettle (3.7.3-1) unstable; urgency=high
+
+ * New upstream release fixing bugs that could make the RSA decryption
+ functions crash on invalid inputs [CVE-2021-3580] (Closes: #989631).
+
+ -- Magnus Holmgren <holmgren@debian.org> Thu, 10 Jun 2021 08:51:41 +0200
+
nettle (3.7.2-3) unstable; urgency=medium
* libnettle8.symbols: Drop two more (internal) symbols from armel and
diff --git a/nettle.pdf b/nettle.pdf
index 14ffd94..1eae00d 100644
Binary files a/nettle.pdf and b/nettle.pdf differ
diff --git a/pkcs1-sec-decrypt.c b/pkcs1-sec-decrypt.c
index 4f13080..942a2bd 100644
--- a/pkcs1-sec-decrypt.c
+++ b/pkcs1-sec-decrypt.c
@@ -63,7 +63,9 @@ _pkcs1_sec_decrypt (size_t length, uint8_t *message,
volatile int ok;
size_t i, t;
- assert (padded_message_length >= length);
+ /* Message independent branch */
+ if (length + 11 > padded_message_length)
+ return 0;
t = padded_message_length - length - 1;
@@ -99,8 +101,8 @@ _pkcs1_sec_decrypt_variable(size_t *length, uint8_t *message,
/* length is discovered in a side-channel silent way.
* not_found goes to 0 when the terminator is found.
- * offset strts at 3 as it includes the terminator and
- * the fomat bytes already */
+ * offset starts at 3 as it includes the terminator and
+ * the format bytes already */
offset = 3;
for (i = 2; i < padded_message_length; i++)
{
diff --git a/rsa-decrypt-tr.c b/rsa-decrypt-tr.c
index 0224c0b..4a9e9d7 100644
--- a/rsa-decrypt-tr.c
+++ b/rsa-decrypt-tr.c
@@ -52,14 +52,17 @@ rsa_decrypt_tr(const struct rsa_public_key *pub,
mp_size_t key_limb_size;
int res;
- key_limb_size = NETTLE_OCTET_SIZE_TO_LIMB_SIZE(key->size);
+ /* First check that input is in range. */
+ if (mpz_sgn (gibberish) < 0 || mpz_cmp (gibberish, pub->n) >= 0)
+ return 0;
+
+ key_limb_size = mpz_size(pub->n);
TMP_GMP_ALLOC (m, key_limb_size);
TMP_GMP_ALLOC (em, key->size);
+ mpz_limbs_copy(m, gibberish, key_limb_size);
- res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, m,
- mpz_limbs_read(gibberish),
- mpz_size(gibberish));
+ res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, m, m);
mpn_get_base256 (em, key->size, m, key_limb_size);
diff --git a/rsa-decrypt.c b/rsa-decrypt.c
index 7681439..540d8ba 100644
--- a/rsa-decrypt.c
+++ b/rsa-decrypt.c
@@ -48,6 +48,16 @@ rsa_decrypt(const struct rsa_private_key *key,
int res;
mpz_init(m);
+
+ /* First check that input is in range. Since we don't have the
+ public key available here, we need to reconstruct n. */
+ mpz_mul (m, key->p, key->q);
+ if (mpz_sgn (gibberish) < 0 || mpz_cmp (gibberish, m) >= 0)
+ {
+ mpz_clear (m);
+ return 0;
+ }
+
rsa_compute_root(key, m, gibberish);
res = pkcs1_decrypt (key->size, m, length, message);
diff --git a/rsa-internal.h b/rsa-internal.h
index b828e45..f66a7df 100644
--- a/rsa-internal.h
+++ b/rsa-internal.h
@@ -78,11 +78,11 @@ _rsa_sec_compute_root(const struct rsa_private_key *key,
mp_limb_t *scratch);
/* Safe side-channel silent variant, using RSA blinding, and checking the
- * result after CRT. */
+ * result after CRT. In-place calls, with x == m, is allowed. */
int
_rsa_sec_compute_root_tr(const struct rsa_public_key *pub,
const struct rsa_private_key *key,
void *random_ctx, nettle_random_func *random,
- mp_limb_t *x, const mp_limb_t *m, size_t mn);
+ mp_limb_t *x, const mp_limb_t *m);
#endif /* NETTLE_RSA_INTERNAL_H_INCLUDED */
diff --git a/rsa-sec-decrypt.c b/rsa-sec-decrypt.c
index 6866e7c..4c98958 100644
--- a/rsa-sec-decrypt.c
+++ b/rsa-sec-decrypt.c
@@ -55,12 +55,19 @@ rsa_sec_decrypt(const struct rsa_public_key *pub,
TMP_GMP_DECL (em, uint8_t);
int res;
+ /* First check that input is in range. */
+ if (mpz_sgn (gibberish) < 0 || mpz_cmp (gibberish, pub->n) >= 0)
+ return 0;
+
TMP_GMP_ALLOC (m, mpz_size(pub->n));
TMP_GMP_ALLOC (em, key->size);
- res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, m,
- mpz_limbs_read(gibberish),
- mpz_size(gibberish));
+ /* We need a copy because m can be shorter than key_size,
+ * but _rsa_sec_compute_root_tr expect all inputs to be
+ * normalized to a key_size long buffer length */
+ mpz_limbs_copy(m, gibberish, mpz_size(pub->n));
+
+ res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, m, m);
mpn_get_base256 (em, key->size, m, mpz_size(pub->n));
diff --git a/rsa-sign-tr.c b/rsa-sign-tr.c
index f824c4c..9e137c7 100644
--- a/rsa-sign-tr.c
+++ b/rsa-sign-tr.c
@@ -131,35 +131,34 @@ int
_rsa_sec_compute_root_tr(const struct rsa_public_key *pub,
const struct rsa_private_key *key,
void *random_ctx, nettle_random_func *random,
- mp_limb_t *x, const mp_limb_t *m, size_t mn)
+ mp_limb_t *x, const mp_limb_t *m)
{
+ mp_size_t nn;
mpz_t mz;
mpz_t xz;
int res;
- mpz_init(mz);
mpz_init(xz);
- mpn_copyi(mpz_limbs_write(mz, mn), m, mn);
- mpz_limbs_finish(mz, mn);
+ nn = mpz_size (pub->n);
- res = rsa_compute_root_tr(pub, key, random_ctx, random, xz, mz);
+ res = rsa_compute_root_tr(pub, key, random_ctx, random, xz,
+ mpz_roinit_n(mz, m, nn));
if (res)
- mpz_limbs_copy(x, xz, mpz_size(pub->n));
+ mpz_limbs_copy(x, xz, nn);
- mpz_clear(mz);
mpz_clear(xz);
return res;
}
#else
/* Blinds m, by computing c = m r^e (mod n), for a random r. Also
- returns the inverse (ri), for use by rsa_unblind. */
+ returns the inverse (ri), for use by rsa_unblind. Must have c != m,
+ no in-place operation.*/
static void
rsa_sec_blind (const struct rsa_public_key *pub,
void *random_ctx, nettle_random_func *random,
- mp_limb_t *c, mp_limb_t *ri, const mp_limb_t *m,
- mp_size_t mn)
+ mp_limb_t *c, mp_limb_t *ri, const mp_limb_t *m)
{
const mp_limb_t *ep = mpz_limbs_read (pub->e);
const mp_limb_t *np = mpz_limbs_read (pub->n);
@@ -177,15 +176,15 @@ rsa_sec_blind (const struct rsa_public_key *pub,
/* c = m*(r^e) mod n */
itch = mpn_sec_powm_itch(nn, ebn, nn);
- i2 = mpn_sec_mul_itch(nn, mn);
+ i2 = mpn_sec_mul_itch(nn, nn);
itch = MAX(itch, i2);
- i2 = mpn_sec_div_r_itch(nn + mn, nn);
+ i2 = mpn_sec_div_r_itch(2*nn, nn);
itch = MAX(itch, i2);
i2 = mpn_sec_invert_itch(nn);
itch = MAX(itch, i2);
- TMP_GMP_ALLOC (tp, nn + mn + itch);
- scratch = tp + nn + mn;
+ TMP_GMP_ALLOC (tp, 2*nn + itch);
+ scratch = tp + 2*nn;
/* ri = r^(-1) */
do
@@ -198,9 +197,8 @@ rsa_sec_blind (const struct rsa_public_key *pub,
while (!mpn_sec_invert (ri, tp, np, nn, 2 * nn * GMP_NUMB_BITS, scratch));
mpn_sec_powm (c, rp, nn, ep, ebn, np, nn, scratch);
- /* normally mn == nn, but m can be smaller in some cases */
- mpn_sec_mul (tp, c, nn, m, mn, scratch);
- mpn_sec_div_r (tp, nn + mn, np, nn, scratch);
+ mpn_sec_mul (tp, c, nn, m, nn, scratch);
+ mpn_sec_div_r (tp, 2*nn, np, nn, scratch);
mpn_copyi(c, tp, nn);
TMP_GMP_FREE (r);
@@ -208,7 +206,7 @@ rsa_sec_blind (const struct rsa_public_key *pub,
TMP_GMP_FREE (tp);
}
-/* m = c ri mod n */
+/* m = c ri mod n. Allows x == c. */
static void
rsa_sec_unblind (const struct rsa_public_key *pub,
mp_limb_t *x, mp_limb_t *ri, const mp_limb_t *c)
@@ -299,7 +297,7 @@ int
_rsa_sec_compute_root_tr(const struct rsa_public_key *pub,
const struct rsa_private_key *key,
void *random_ctx, nettle_random_func *random,
- mp_limb_t *x, const mp_limb_t *m, size_t mn)
+ mp_limb_t *x, const mp_limb_t *m)
{
TMP_GMP_DECL (c, mp_limb_t);
TMP_GMP_DECL (ri, mp_limb_t);
@@ -307,7 +305,7 @@ _rsa_sec_compute_root_tr(const struct rsa_public_key *pub,
size_t key_limb_size;
int ret;
- key_limb_size = NETTLE_OCTET_SIZE_TO_LIMB_SIZE(key->size);
+ key_limb_size = mpz_size(pub->n);
/* mpz_powm_sec handles only odd moduli. If p, q or n is even, the
key is invalid and rejected by rsa_private_key_prepare. However,
@@ -321,19 +319,18 @@ _rsa_sec_compute_root_tr(const struct rsa_public_key *pub,
}
assert(mpz_size(pub->n) == key_limb_size);
- assert(mn <= key_limb_size);
TMP_GMP_ALLOC (c, key_limb_size);
TMP_GMP_ALLOC (ri, key_limb_size);
TMP_GMP_ALLOC (scratch, _rsa_sec_compute_root_itch(key));
- rsa_sec_blind (pub, random_ctx, random, x, ri, m, mn);
+ rsa_sec_blind (pub, random_ctx, random, c, ri, m);
- _rsa_sec_compute_root(key, c, x, scratch);
+ _rsa_sec_compute_root(key, x, c, scratch);
- ret = rsa_sec_check_root(pub, c, x);
+ ret = rsa_sec_check_root(pub, x, c);
- rsa_sec_unblind(pub, x, ri, c);
+ rsa_sec_unblind(pub, x, ri, x);
cnd_mpn_zero(1 - ret, x, key_limb_size);
@@ -357,17 +354,17 @@ rsa_compute_root_tr(const struct rsa_public_key *pub,
mpz_t x, const mpz_t m)
{
TMP_GMP_DECL (l, mp_limb_t);
+ mp_size_t nn = mpz_size(pub->n);
int res;
- mp_size_t l_size = NETTLE_OCTET_SIZE_TO_LIMB_SIZE(key->size);
- TMP_GMP_ALLOC (l, l_size);
+ TMP_GMP_ALLOC (l, nn);
+ mpz_limbs_copy(l, m, nn);
- res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, l,
- mpz_limbs_read(m), mpz_size(m));
+ res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, l, l);
if (res) {
- mp_limb_t *xp = mpz_limbs_write (x, l_size);
- mpn_copyi (xp, l, l_size);
- mpz_limbs_finish (x, l_size);
+ mp_limb_t *xp = mpz_limbs_write (x, nn);
+ mpn_copyi (xp, l, nn);
+ mpz_limbs_finish (x, nn);
}
TMP_GMP_FREE (l);
diff --git a/rsa.h b/rsa.h
index 3b10155..2dd35a2 100644
--- a/rsa.h
+++ b/rsa.h
@@ -428,13 +428,14 @@ rsa_sec_decrypt(const struct rsa_public_key *pub,
size_t length, uint8_t *message,
const mpz_t gibberish);
-/* Compute x, the e:th root of m. Calling it with x == m is allowed. */
+/* Compute x, the e:th root of m. Calling it with x == m is allowed.
+ It is required that 0 <= m < n. */
void
rsa_compute_root(const struct rsa_private_key *key,
mpz_t x, const mpz_t m);
/* Safer variant, using RSA blinding, and checking the result after
- CRT. */
+ CRT. It is required that 0 <= m < n. */
int
rsa_compute_root_tr(const struct rsa_public_key *pub,
const struct rsa_private_key *key,
diff --git a/testsuite/rsa-encrypt-test.c b/testsuite/rsa-encrypt-test.c
index 87525f7..d1a440f 100644
--- a/testsuite/rsa-encrypt-test.c
+++ b/testsuite/rsa-encrypt-test.c
@@ -19,10 +19,12 @@ test_main(void)
uint8_t after;
mpz_t gibberish;
+ mpz_t bad_input;
rsa_private_key_init(&key);
rsa_public_key_init(&pub);
mpz_init(gibberish);
+ mpz_init(bad_input);
knuth_lfib_init(&lfib, 17);
@@ -101,6 +103,42 @@ test_main(void)
ASSERT(decrypted[decrypted_length] == after);
ASSERT(decrypted[0] == 'A');
+ /* Test zero input. */
+ mpz_set_ui (bad_input, 0);
+ decrypted_length = msg_length;
+ ASSERT(!rsa_decrypt(&key, &decrypted_length, decrypted, bad_input));
+ ASSERT(!rsa_decrypt_tr(&pub, &key,
+ &lfib, (nettle_random_func *) knuth_lfib_random,
+ &decrypted_length, decrypted, bad_input));
+ ASSERT(!rsa_sec_decrypt(&pub, &key,
+ &lfib, (nettle_random_func *) knuth_lfib_random,
+ decrypted_length, decrypted, bad_input));
+ ASSERT(decrypted_length == msg_length);
+
+ /* Test input that is slightly larger than n */
+ mpz_add(bad_input, gibberish, pub.n);
+ decrypted_length = msg_length;
+ ASSERT(!rsa_decrypt(&key, &decrypted_length, decrypted, bad_input));
+ ASSERT(!rsa_decrypt_tr(&pub, &key,
+ &lfib, (nettle_random_func *) knuth_lfib_random,
+ &decrypted_length, decrypted, bad_input));
+ ASSERT(!rsa_sec_decrypt(&pub, &key,
+ &lfib, (nettle_random_func *) knuth_lfib_random,
+ decrypted_length, decrypted, bad_input));
+ ASSERT(decrypted_length == msg_length);
+
+ /* Test input that is considerably larger than n */
+ mpz_mul_2exp (bad_input, pub.n, 100);
+ mpz_add (bad_input, bad_input, gibberish);
+ decrypted_length = msg_length;
+ ASSERT(!rsa_decrypt(&key, &decrypted_length, decrypted, bad_input));
+ ASSERT(!rsa_decrypt_tr(&pub, &key,
+ &lfib, (nettle_random_func *) knuth_lfib_random,
+ &decrypted_length, decrypted, bad_input));
+ ASSERT(!rsa_sec_decrypt(&pub, &key,
+ &lfib, (nettle_random_func *) knuth_lfib_random,
+ decrypted_length, decrypted, bad_input));
+ ASSERT(decrypted_length == msg_length);
/* Test invalid key. */
mpz_add_ui (key.q, key.q, 2);
@@ -112,6 +150,6 @@ test_main(void)
rsa_private_key_clear(&key);
rsa_public_key_clear(&pub);
mpz_clear(gibberish);
+ mpz_clear(bad_input);
free(decrypted);
}
-
diff --git a/testsuite/rsa-sec-decrypt-test.c b/testsuite/rsa-sec-decrypt-test.c
index fb0ed3a..3419322 100644
--- a/testsuite/rsa-sec-decrypt-test.c
+++ b/testsuite/rsa-sec-decrypt-test.c
@@ -55,6 +55,7 @@ rsa_decrypt_for_test(const struct rsa_public_key *pub,
#endif
#define PAYLOAD_SIZE 50
+#define DECRYPTED_SIZE 256
void
test_main(void)
{
@@ -63,7 +64,7 @@ test_main(void)
struct knuth_lfib_ctx random_ctx;
uint8_t plaintext[PAYLOAD_SIZE];
- uint8_t decrypted[PAYLOAD_SIZE];
+ uint8_t decrypted[DECRYPTED_SIZE];
uint8_t verifybad[PAYLOAD_SIZE];
unsigned n_size = 1024;
mpz_t gibberish;
@@ -99,6 +100,20 @@ test_main(void)
PAYLOAD_SIZE, decrypted, gibberish) == 1);
ASSERT (MEMEQ (PAYLOAD_SIZE, plaintext, decrypted));
+ ASSERT (pub.size > 10);
+ ASSERT (pub.size <= DECRYPTED_SIZE);
+
+ /* Check that too large message length is rejected, largest
+ valid size is pub.size - 11. */
+ ASSERT (!rsa_decrypt_for_test (&pub, &key, &random_ctx,
+ (nettle_random_func *) knuth_lfib_random,
+ pub.size - 10, decrypted, gibberish));
+
+ /* This case used to result in arithmetic underflow and a crash. */
+ ASSERT (!rsa_decrypt_for_test (&pub, &key, &random_ctx,
+ (nettle_random_func *) knuth_lfib_random,
+ pub.size, decrypted, gibberish));
+
/* bad one */
memcpy(decrypted, verifybad, PAYLOAD_SIZE);
nettle_mpz_random_size(garbage, &random_ctx,
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