Control: tags -1 moreinfo confirmed
On 2021-06-10 08:53:10 +0200, Magnus Holmgren wrote:
> 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.
ACK, please remove the moreinf otag once the new version is available in
unstable.
Cheers
>
> (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,
--
Sebastian Ramacher
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