security/openssl: Security update for CVE-2024-9143

Security: c6f4177c-8e29-11ef-98e7-84a93843eb75 MFH: 2024Q4
2024-11-18 00:10:04 +00:00 · 2024-10-19 16:58:59 +02:00 · 2024-10-19 16:58:59 +02:00 · 7eba61f802
commit 7eba61f802
parent d0f01687dc
2 changed files with 199 additions and 0 deletions
--- a/security/openssl/Makefile
+++ b/security/openssl/Makefile
@ -1,5 +1,6 @@
 PORTNAME=	openssl
 PORTVERSION=	3.0.15
+PORTREVISION=	1
 PORTEPOCH=	1
 CATEGORIES=	security devel

--- a/security/openssl/files/patch-CVE-2024-9143
+++ b/security/openssl/files/patch-CVE-2024-9143
@ -0,0 +1,198 @@
+From 72ae83ad214d2eef262461365a1975707f862712 Mon Sep 17 00:00:00 2001
+From: Viktor Dukhovni <viktor@openssl.org>
+Date: Thu, 19 Sep 2024 01:02:40 +1000
+Subject: [PATCH] Harden BN_GF2m_poly2arr against misuse.
+
+The BN_GF2m_poly2arr() function converts characteristic-2 field
+(GF_{2^m}) Galois polynomials from a representation as a BIGNUM bitmask,
+to a compact array with just the exponents of the non-zero terms.
+
+These polynomials are then used in BN_GF2m_mod_arr() to perform modular
+reduction.  A precondition of calling BN_GF2m_mod_arr() is that the
+polynomial must have a non-zero constant term (i.e. the array has `0` as
+its final element).
+
+Internally, callers of BN_GF2m_poly2arr() did not verify that
+precondition, and binary EC curve parameters with an invalid polynomial
+could lead to out of bounds memory reads and writes in BN_GF2m_mod_arr().
+
+The precondition is always true for polynomials that arise from the
+standard form of EC parameters for characteristic-two fields (X9.62).
+See the "Finite Field Identification" section of:
+
+    https://www.itu.int/ITU-T/formal-language/itu-t/x/x894/2018-cor1/ANSI-X9-62.html
+
+The OpenSSL GF(2^m) code supports only the trinomial and pentanomial
+basis X9.62 forms.
+
+This commit updates BN_GF2m_poly2arr() to return `0` (failure) when
+the constant term is zero (i.e. the input bitmask BIGNUM is not odd).
+
+Additionally, the return value is made unambiguous when there is not
+enough space to also pad the array with a final `-1` sentinel value.
+The return value is now always the number of elements (including the
+final `-1`) that would be filled when the output array is sufficiently
+large.  Previously the same count was returned both when the array has
+just enough room for the final `-1` and when it had only enough space
+for non-sentinel values.
+
+Finally, BN_GF2m_poly2arr() is updated to reject polynomials whose
+degree exceeds `OPENSSL_ECC_MAX_FIELD_BITS`, this guards against
+CPU exhausition attacks via excessively large inputs.
+
+The above issues do not arise in processing X.509 certificates.  These
+generally have EC keys from "named curves", and RFC5840 (Section 2.1.1)
+disallows explicit EC parameters.  The TLS code in OpenSSL enforces this
+constraint only after the certificate is decoded, but, even if explicit
+parameters are specified, they are in X9.62 form, which cannot represent
+problem values as noted above.
+
+Initially reported as oss-fuzz issue 71623.
+
+A closely related issue was earlier reported in
+<https://github.com/openssl/openssl/issues/19826>.
+
+Severity: Low, CVE-2024-9143
+
+Reviewed-by: Matt Caswell <matt@openssl.org>
+Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
+Reviewed-by: Paul Dale <ppzgs1@gmail.com>
+Reviewed-by: Tomas Mraz <tomas@openssl.org>
+(Merged from https://github.com/openssl/openssl/pull/25639)
+
+(cherry picked from commit 8e008cb8b23ec7dc75c45a66eeed09c815b11cd2)
+---
+ crypto/bn/bn_gf2m.c     | 28 +++++++++++++++-------
+ test/ec_internal_test.c | 51 +++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 71 insertions(+), 8 deletions(-)
+
+diff --git a/crypto/bn/bn_gf2m.c b/crypto/bn/bn_gf2m.c
+index c811ae82d6b15..bcc66613cc14d 100644
+--- crypto/bn/bn_gf2m.c.orig
+++ crypto/bn/bn_gf2m.c
+@@ -15,6 +15,7 @@
+ #include "bn_local.h"
+ 
+ #ifndef OPENSSL_NO_EC2M
+# include <openssl/ec.h>
+ 
+ /*
+  * Maximum number of iterations before BN_GF2m_mod_solve_quad_arr should
+@@ -1140,16 +1141,26 @@ int BN_GF2m_mod_solve_quad(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+ /*
+  * Convert the bit-string representation of a polynomial ( \sum_{i=0}^n a_i *
+  * x^i) into an array of integers corresponding to the bits with non-zero
+- * coefficient.  Array is terminated with -1. Up to max elements of the array
+- * will be filled.  Return value is total number of array elements that would
+- * be filled if array was large enough.
+ * coefficient.  The array is intended to be suitable for use with
+ * `BN_GF2m_mod_arr()`, and so the constant term of the polynomial must not be
+ * zero.  This translates to a requirement that the input BIGNUM `a` is odd.
+ *
+ * Given sufficient room, the array is terminated with -1.  Up to max elements
+ * of the array will be filled.
+ *
+ * The return value is total number of array elements that would be filled if
+ * array was large enough, including the terminating `-1`.  It is `0` when `a`
+ * is not odd or the constant term is zero contrary to requirement.
+ *
+ * The return value is also `0` when the leading exponent exceeds
+ * `OPENSSL_ECC_MAX_FIELD_BITS`, this guards against CPU exhaustion attacks,
+  */
+ int BN_GF2m_poly2arr(const BIGNUM *a, int p[], int max)
+ {
+     int i, j, k = 0;
+     BN_ULONG mask;
+ 
+-    if (BN_is_zero(a))
+    if (!BN_is_odd(a))
+         return 0;
+ 
+     for (i = a->top - 1; i >= 0; i--) {
+@@ -1167,12 +1178,13 @@ int BN_GF2m_poly2arr(const BIGNUM *a, int p[], int max)
+         }
+     }
+ 
+-    if (k < max) {
+    if (k > 0 && p[0] > OPENSSL_ECC_MAX_FIELD_BITS)
+        return 0;
+
+    if (k < max)
+         p[k] = -1;
+-        k++;
+-    }
+ 
+-    return k;
+    return k + 1;
+ }
+ 
+ /*
+diff --git a/test/ec_internal_test.c b/test/ec_internal_test.c
+index 8c2cd05631696..02cfd4e9d8858 100644
+--- test/ec_internal_test.c.orig
+++ test/ec_internal_test.c
+@@ -155,6 +155,56 @@ static int field_tests_ecp_mont(void)
+ }
+ 
+ #ifndef OPENSSL_NO_EC2M
+/* Test that decoding of invalid GF2m field parameters fails. */
+static int ec2m_field_sanity(void)
+{
+    int ret = 0;
+    BN_CTX *ctx = BN_CTX_new();
+    BIGNUM *p, *a, *b;
+    EC_GROUP *group1 = NULL, *group2 = NULL, *group3 = NULL;
+
+    TEST_info("Testing GF2m hardening\n");
+
+    BN_CTX_start(ctx);
+    p = BN_CTX_get(ctx);
+    a = BN_CTX_get(ctx);
+    if (!TEST_ptr(b = BN_CTX_get(ctx))
+        || !TEST_true(BN_one(a))
+        || !TEST_true(BN_one(b)))
+        goto out;
+
+    /* Even pentanomial value should be rejected */
+    if (!TEST_true(BN_set_word(p, 0xf2)))
+        goto out;
+    if (!TEST_ptr_null(group1 = EC_GROUP_new_curve_GF2m(p, a, b, ctx)))
+        TEST_error("Zero constant term accepted in GF2m polynomial");
+
+    /* Odd hexanomial should also be rejected */
+    if (!TEST_true(BN_set_word(p, 0xf3)))
+        goto out;
+    if (!TEST_ptr_null(group2 = EC_GROUP_new_curve_GF2m(p, a, b, ctx)))
+        TEST_error("Hexanomial accepted as GF2m polynomial");
+
+    /* Excessive polynomial degree should also be rejected */
+    if (!TEST_true(BN_set_word(p, 0x71))
+        || !TEST_true(BN_set_bit(p, OPENSSL_ECC_MAX_FIELD_BITS + 1)))
+        goto out;
+    if (!TEST_ptr_null(group3 = EC_GROUP_new_curve_GF2m(p, a, b, ctx)))
+        TEST_error("GF2m polynomial degree > %d accepted",
+                   OPENSSL_ECC_MAX_FIELD_BITS);
+
+    ret = group1 == NULL && group2 == NULL && group3 == NULL;
+
+ out:
+    EC_GROUP_free(group1);
+    EC_GROUP_free(group2);
+    EC_GROUP_free(group3);
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+
+    return ret;
+}
+
+ /* test EC_GF2m_simple_method directly */
+ static int field_tests_ec2_simple(void)
+ {
+@@ -443,6 +493,7 @@ int setup_tests(void)
+     ADD_TEST(field_tests_ecp_simple);
+     ADD_TEST(field_tests_ecp_mont);
+ #ifndef OPENSSL_NO_EC2M
+    ADD_TEST(ec2m_field_sanity);
+     ADD_TEST(field_tests_ec2_simple);
+ #endif
+     ADD_ALL_TESTS(field_tests_default, crv_len);