diff options
| -rw-r--r-- | gnu/local.mk | 3 | ||||
| -rw-r--r-- | gnu/packages/nettle.scm | 11 | ||||
| -rw-r--r-- | gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt1.patch | 276 | ||||
| -rw-r--r-- | gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt2.patch | 163 | ||||
| -rw-r--r-- | gnu/packages/patches/nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch | 78 |
5 files changed, 530 insertions, 1 deletions
diff --git a/gnu/local.mk b/gnu/local.mk index fdbf2272ed..f1a6d69bf6 100644 --- a/gnu/local.mk +++ b/gnu/local.mk @@ -1462,6 +1462,9 @@ dist_patch_DATA = \ %D%/packages/patches/netsurf-system-utf8proc.patch \ %D%/packages/patches/netsurf-y2038-tests.patch \ %D%/packages/patches/netsurf-longer-test-timeout.patch \ + %D%/packages/patches/nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch \ + %D%/packages/patches/nettle-3.5-CVE-2021-3580-pt1.patch \ + %D%/packages/patches/nettle-3.5-CVE-2021-3580-pt2.patch \ %D%/packages/patches/nfs4-acl-tools-0.3.7-fixpaths.patch \ %D%/packages/patches/ngircd-handle-zombies.patch \ %D%/packages/patches/network-manager-plugin-path.patch \ diff --git a/gnu/packages/nettle.scm b/gnu/packages/nettle.scm index 753e2d6e7e..3d394dc746 100644 --- a/gnu/packages/nettle.scm +++ b/gnu/packages/nettle.scm @@ -1,6 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2012, 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org> -;;; Copyright © 2016 Mark H Weaver <mhw@netris.org> +;;; Copyright © 2016, 2021 Mark H Weaver <mhw@netris.org> ;;; Copyright © 2017 Efraim Flashner <efraim@flashner.co.il> ;;; Copyright © 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com> ;;; @@ -25,6 +25,7 @@ #:use-module (guix packages) #:use-module (guix download) #:use-module (guix build-system gnu) + #:use-module (gnu packages) #:use-module (gnu packages multiprecision) #:use-module (gnu packages m4)) @@ -77,6 +78,7 @@ themselves.") ;; cannot use it yet. So keep it separate. (package (inherit nettle-2) (version "3.5.1") + (replacement nettle-3.5/fixed) (source (origin (method url-fetch) (uri (string-append "mirror://gnu/nettle/nettle-" @@ -91,6 +93,13 @@ themselves.") ;; at run time based on CPU features (starting from 3.1.) `(cons "--enable-fat" ,flags)))))) +(define nettle-3.5/fixed + (package-with-extra-patches + nettle-3.5 + (search-patches "nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch" + "nettle-3.5-CVE-2021-3580-pt1.patch" + "nettle-3.5-CVE-2021-3580-pt2.patch"))) + (define-public nettle-3.7 (package (inherit nettle-3.5) (version "3.7.2") diff --git a/gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt1.patch b/gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt1.patch new file mode 100644 index 0000000000..4343c87795 --- /dev/null +++ b/gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt1.patch @@ -0,0 +1,276 @@ +Copied from upstream nettle git repository. +Removed changes to ChangeLog, to allow this patch to apply to nettle-3.5. + +From 485b5e2820a057e873b1ba812fdb39cae4adf98c Mon Sep 17 00:00:00 2001 +From: Niels Möller <nisse@lysator.liu.se> +Date: Mon, 17 May 2021 20:55:26 +0200 +Subject: [PATCH 1/2] Change _rsa_sec_compute_root_tr to take a fix input size. + +Improves consistency with _rsa_sec_compute_root, and fixes zero-input bug. +--- + ChangeLog | 15 +++++++++ + rsa-decrypt-tr.c | 7 ++--- + rsa-internal.h | 4 +-- + rsa-sec-decrypt.c | 9 ++++-- + rsa-sign-tr.c | 61 +++++++++++++++++------------------- + testsuite/rsa-encrypt-test.c | 14 ++++++++- + 6 files changed, 68 insertions(+), 42 deletions(-) + +diff --git a/rsa-decrypt-tr.c b/rsa-decrypt-tr.c +index 0224c0b7..927a8915 100644 +--- a/rsa-decrypt-tr.c ++++ b/rsa-decrypt-tr.c +@@ -52,14 +52,13 @@ 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); ++ 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-internal.h b/rsa-internal.h +index b828e451..f66a7df0 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 6866e7c8..fc4757a0 100644 +--- a/rsa-sec-decrypt.c ++++ b/rsa-sec-decrypt.c +@@ -58,9 +58,12 @@ rsa_sec_decrypt(const struct rsa_public_key *pub, + 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 f824c4ca..9e137c7a 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/testsuite/rsa-encrypt-test.c b/testsuite/rsa-encrypt-test.c +index 87525f78..d3bc374b 100644 +--- a/testsuite/rsa-encrypt-test.c ++++ b/testsuite/rsa-encrypt-test.c +@@ -19,6 +19,7 @@ test_main(void) + uint8_t after; + + mpz_t gibberish; ++ mpz_t zero; + + rsa_private_key_init(&key); + rsa_public_key_init(&pub); +@@ -101,6 +102,17 @@ test_main(void) + ASSERT(decrypted[decrypted_length] == after); + ASSERT(decrypted[0] == 'A'); + ++ /* Test zero input. */ ++ mpz_init_set_ui (zero, 0); ++ decrypted_length = msg_length; ++ ASSERT(!rsa_decrypt(&key, &decrypted_length, decrypted, zero)); ++ ASSERT(!rsa_decrypt_tr(&pub, &key, ++ &lfib, (nettle_random_func *) knuth_lfib_random, ++ &decrypted_length, decrypted, zero)); ++ ASSERT(!rsa_sec_decrypt(&pub, &key, ++ &lfib, (nettle_random_func *) knuth_lfib_random, ++ decrypted_length, decrypted, zero)); ++ ASSERT(decrypted_length == msg_length); + + /* Test invalid key. */ + mpz_add_ui (key.q, key.q, 2); +@@ -112,6 +124,6 @@ test_main(void) + rsa_private_key_clear(&key); + rsa_public_key_clear(&pub); + mpz_clear(gibberish); ++ mpz_clear(zero); + free(decrypted); + } +- +-- +2.31.1 + diff --git a/gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt2.patch b/gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt2.patch new file mode 100644 index 0000000000..5f19bd80d3 --- /dev/null +++ b/gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt2.patch @@ -0,0 +1,163 @@ +Copied from upstream nettle git repository. +Removed changes to ChangeLog, to allow this patch to apply to nettle-3.5. + +From 0ad0b5df315665250dfdaa4a1e087f4799edaefe Mon Sep 17 00:00:00 2001 +From: Niels Möller <nisse@lysator.liu.se> +Date: Mon, 17 May 2021 22:02:47 +0200 +Subject: [PATCH 2/2] Add input check to rsa_decrypt family of functions. + +--- + ChangeLog | 8 ++++++++ + rsa-decrypt-tr.c | 4 ++++ + rsa-decrypt.c | 10 ++++++++++ + rsa-sec-decrypt.c | 4 ++++ + rsa.h | 5 +++-- + testsuite/rsa-encrypt-test.c | 38 ++++++++++++++++++++++++++++++------ + 6 files changed, 61 insertions(+), 8 deletions(-) + +diff --git a/rsa-decrypt-tr.c b/rsa-decrypt-tr.c +index 927a8915..4a9e9d74 100644 +--- a/rsa-decrypt-tr.c ++++ b/rsa-decrypt-tr.c +@@ -52,6 +52,10 @@ rsa_decrypt_tr(const struct rsa_public_key *pub, + mp_size_t key_limb_size; + int res; + ++ /* 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); +diff --git a/rsa-decrypt.c b/rsa-decrypt.c +index 7681439d..540d8baa 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-sec-decrypt.c b/rsa-sec-decrypt.c +index fc4757a0..4c98958d 100644 +--- a/rsa-sec-decrypt.c ++++ b/rsa-sec-decrypt.c +@@ -55,6 +55,10 @@ 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); + +diff --git a/rsa.h b/rsa.h +index 3b10155f..2dd35a2d 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 d3bc374b..d1a440f6 100644 +--- a/testsuite/rsa-encrypt-test.c ++++ b/testsuite/rsa-encrypt-test.c +@@ -19,11 +19,12 @@ test_main(void) + uint8_t after; + + mpz_t gibberish; +- mpz_t zero; ++ 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); + +@@ -103,15 +104,40 @@ test_main(void) + ASSERT(decrypted[0] == 'A'); + + /* Test zero input. */ +- mpz_init_set_ui (zero, 0); ++ mpz_set_ui (bad_input, 0); + decrypted_length = msg_length; +- ASSERT(!rsa_decrypt(&key, &decrypted_length, decrypted, zero)); ++ 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, zero)); ++ &decrypted_length, decrypted, bad_input)); + ASSERT(!rsa_sec_decrypt(&pub, &key, + &lfib, (nettle_random_func *) knuth_lfib_random, +- decrypted_length, decrypted, zero)); ++ 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. */ +@@ -124,6 +150,6 @@ test_main(void) + rsa_private_key_clear(&key); + rsa_public_key_clear(&pub); + mpz_clear(gibberish); +- mpz_clear(zero); ++ mpz_clear(bad_input); + free(decrypted); + } +-- +2.31.1 + diff --git a/gnu/packages/patches/nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch b/gnu/packages/patches/nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch new file mode 100644 index 0000000000..297816e698 --- /dev/null +++ b/gnu/packages/patches/nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch @@ -0,0 +1,78 @@ +Copied from upstream nettle git repository. +Removed changes to ChangeLog, to allow this patch to apply to nettle-3.5. + +From 7616541e6eff73353bf682c62e3a68e4fe696707 Mon Sep 17 00:00:00 2001 +From: Niels Möller <nisse@lysator.liu.se> +Date: Thu, 6 May 2021 21:29:56 +0200 +Subject: [PATCH] Add check that message length to _pkcs1_sec_decrypt is valid. + +* 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. +--- + ChangeLog | 7 +++++++ + pkcs1-sec-decrypt.c | 4 +++- + testsuite/rsa-sec-decrypt-test.c | 17 ++++++++++++++++- + 3 files changed, 26 insertions(+), 2 deletions(-) + +diff --git a/pkcs1-sec-decrypt.c b/pkcs1-sec-decrypt.c +index 4f13080e..16833691 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; + +diff --git a/testsuite/rsa-sec-decrypt-test.c b/testsuite/rsa-sec-decrypt-test.c +index fb0ed3a1..3419322e 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, +-- +2.31.1 + |