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01/02: gnu: nettle-3.5: Add replacement to fix CVE-2021-3580 et al.
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guix-commits |
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Subject: |
01/02: gnu: nettle-3.5: Add replacement to fix CVE-2021-3580 et al. |
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Date: |
Mon, 14 Jun 2021 03:31:30 -0400 (EDT) |
mhw pushed a commit to branch master
in repository guix.
commit 3abaca2aaed87927b18d80381fe64897ac889f8c
Author: Mark H Weaver <mhw@netris.org>
AuthorDate: Sun Jun 13 20:03:29 2021 -0400
gnu: nettle-3.5: Add replacement to fix CVE-2021-3580 et al.
* gnu/packages/patches/nettle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch,
gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt1.patch,
gnu/packages/patches/nettle-3.5-CVE-2021-3580-pt2.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
* gnu/packages/nettle.scm (nettle)[replacement]: New field.
(nettle-3.5/fixed): New variable.
---
gnu/local.mk | 3 +
gnu/packages/nettle.scm | 11 +-
.../patches/nettle-3.5-CVE-2021-3580-pt1.patch | 276 +++++++++++++++++++++
.../patches/nettle-3.5-CVE-2021-3580-pt2.patch | 163 ++++++++++++
...ttle-3.5-check-_pkcs1_sec_decrypt-msg-len.patch | 78 ++++++
5 files changed, 530 insertions(+), 1 deletion(-)
diff --git a/gnu/local.mk b/gnu/local.mk
index fdbf227..f1a6d69 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 753e2d6..3d394dc 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 0000000..4343c87
--- /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 0000000..5f19bd8
--- /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 0000000..297816e
--- /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
+