From 1fba75a6203d3ea2037d2fc2e1846f1b514c3d1d Mon Sep 17 00:00:00 2001
From: rpm-build <rpm-build>
Date: Wed, 6 Mar 2024 19:17:15 +0100
Subject: [PATCH 23/49]
0052-Allow-SHA1-in-seclevel-1-if-rh-allow-sha1-signatures.patch
Patch-name: 0052-Allow-SHA1-in-seclevel-1-if-rh-allow-sha1-signatures.patch
Patch-id: 52
Patch-status: |
# # Support SHA1 in TLS in LEGACY crypto-policy (which is SECLEVEL=1)
From-dist-git-commit: 4334bc837fbc64d14890fdc51679a80770d498ce
---
crypto/x509/x509_vfy.c | 20 ++++++++++-
doc/man5/config.pod | 7 ++++
ssl/t1_lib.c | 67 ++++++++++++++++++++++++++++-------
test/recipes/25-test_verify.t | 4 +--
4 files changed, 82 insertions(+), 16 deletions(-)
diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c
index 1794c14e99..1dfbe58a4a 100644
--- a/crypto/x509/x509_vfy.c
+++ b/crypto/x509/x509_vfy.c
@@ -25,6 +25,7 @@
#include <openssl/objects.h>
#include <openssl/core_names.h>
#include "internal/dane.h"
+#include "internal/sslconf.h"
#include "crypto/x509.h"
#include "x509_local.h"
@@ -3668,14 +3669,31 @@ static int check_sig_level(X509_STORE_CTX *ctx, X509 *cert)
{
int secbits = -1;
int level = ctx->param->auth_level;
+ int nid;
+ OSSL_LIB_CTX *libctx = NULL;
if (level <= 0)
return 1;
if (level > NUM_AUTH_LEVELS)
level = NUM_AUTH_LEVELS;
- if (!X509_get_signature_info(cert, NULL, NULL, &secbits, NULL))
+ if (ctx->libctx)
+ libctx = ctx->libctx;
+ else if (cert->libctx)
+ libctx = cert->libctx;
+ else
+ libctx = OSSL_LIB_CTX_get0_global_default();
+
+ if (!X509_get_signature_info(cert, &nid, NULL, &secbits, NULL))
return 0;
+ if ((nid == NID_sha1 || nid == NID_md5_sha1)
+ && ossl_ctx_legacy_digest_signatures_allowed(libctx, 0)
+ && ctx->param->auth_level < 2)
+ /* When rh-allow-sha1-signatures = yes and security level <= 1,
+ * explicitly allow SHA1 for backwards compatibility. Also allow
+ * MD5-SHA1 because TLS 1.0 is still supported, which uses it. */
+ return 1;
+
return secbits >= minbits_table[level - 1];
}
diff --git a/doc/man5/config.pod b/doc/man5/config.pod
index ed34ff4b9c..8ab5456c99 100644
--- a/doc/man5/config.pod
+++ b/doc/man5/config.pod
@@ -317,6 +317,13 @@ this option is set to B<no>. Because TLS 1.1 or lower use MD5-SHA1 as
pseudorandom function (PRF) to derive key material, disabling
B<rh-allow-sha1-signatures> requires the use of TLS 1.2 or newer.
+Note that enabling B<rh-allow-sha1-signatures> will allow TLS signature
+algorithms that use SHA1 in security level 1, despite the definition of
+security level 1 of 80 bits of security, which SHA1 and MD5-SHA1 do not meet.
+This allows using SHA1 and MD5-SHA1 in TLS in the LEGACY crypto-policy on
+Fedora without requiring to set the security level to 0, which would include
+further insecure algorithms, and thus restores support for TLS 1.0 and 1.1.
+
=item B<fips_mode> (deprecated)
The value is a boolean that can be B<yes> or B<no>. If the value is
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 05dd7c5595..056aae3863 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -20,6 +20,7 @@
#include <openssl/bn.h>
#include <openssl/provider.h>
#include <openssl/param_build.h>
+#include "crypto/x509.h"
#include "internal/sslconf.h"
#include "internal/nelem.h"
#include "internal/sizes.h"
@@ -1977,19 +1978,28 @@ int tls12_check_peer_sigalg(SSL_CONNECTION *s, uint16_t sig, EVP_PKEY *pkey)
SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_UNKNOWN_DIGEST);
return 0;
}
- /*
- * Make sure security callback allows algorithm. For historical
- * reasons we have to pass the sigalg as a two byte char array.
- */
- sigalgstr[0] = (sig >> 8) & 0xff;
- sigalgstr[1] = sig & 0xff;
- secbits = sigalg_security_bits(SSL_CONNECTION_GET_CTX(s), lu);
- if (secbits == 0 ||
- !ssl_security(s, SSL_SECOP_SIGALG_CHECK, secbits,
- md != NULL ? EVP_MD_get_type(md) : NID_undef,
- (void *)sigalgstr)) {
- SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_WRONG_SIGNATURE_TYPE);
- return 0;
+
+ if ((lu->hash == NID_sha1 || lu->hash == NID_md5_sha1)
+ && ossl_ctx_legacy_digest_signatures_allowed(s->session_ctx->libctx, 0)
+ && SSL_get_security_level(SSL_CONNECTION_GET_SSL(s)) < 2) {
+ /* When rh-allow-sha1-signatures = yes and security level <= 1,
+ * explicitly allow SHA1 for backwards compatibility. Also allow
+ * MD5-SHA1 because TLS 1.0 is still supported, which uses it. */
+ } else {
+ /*
+ * Make sure security callback allows algorithm. For historical
+ * reasons we have to pass the sigalg as a two byte char array.
+ */
+ sigalgstr[0] = (sig >> 8) & 0xff;
+ sigalgstr[1] = sig & 0xff;
+ secbits = sigalg_security_bits(s->session_ctx, lu);
+ if (secbits == 0 ||
+ !ssl_security(s, SSL_SECOP_SIGALG_CHECK, secbits,
+ md != NULL ? EVP_MD_get_type(md) : NID_undef,
+ (void *)sigalgstr)) {
+ SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_WRONG_SIGNATURE_TYPE);
+ return 0;
+ }
}
/* Store the sigalg the peer uses */
s->s3.tmp.peer_sigalg = lu;
@@ -2563,6 +2573,15 @@ static int tls12_sigalg_allowed(const SSL_CONNECTION *s, int op,
}
}
+ if ((lu->hash == NID_sha1 || lu->hash == NID_md5_sha1)
+ && ossl_ctx_legacy_digest_signatures_allowed(s->session_ctx->libctx, 0)
+ && SSL_get_security_level(SSL_CONNECTION_GET_SSL(s)) < 2) {
+ /* When rh-allow-sha1-signatures = yes and security level <= 1,
+ * explicitly allow SHA1 for backwards compatibility. Also allow
+ * MD5-SHA1 because TLS 1.0 is still supported, which uses it. */
+ return 1;
+ }
+
/* Finally see if security callback allows it */
secbits = sigalg_security_bits(SSL_CONNECTION_GET_CTX(s), lu);
sigalgstr[0] = (lu->sigalg >> 8) & 0xff;
@@ -3467,6 +3486,8 @@ static int ssl_security_cert_sig(SSL_CONNECTION *s, SSL_CTX *ctx, X509 *x,
{
/* Lookup signature algorithm digest */
int secbits, nid, pknid;
+ OSSL_LIB_CTX *libctx = NULL;
+
/* Don't check signature if self signed */
if ((X509_get_extension_flags(x) & EXFLAG_SS) != 0)
@@ -3476,6 +3497,26 @@ static int ssl_security_cert_sig(SSL_CONNECTION *s, SSL_CTX *ctx, X509 *x,
/* If digest NID not defined use signature NID */
if (nid == NID_undef)
nid = pknid;
+
+ if (x && x->libctx)
+ libctx = x->libctx;
+ else if (ctx && ctx->libctx)
+ libctx = ctx->libctx;
+ else if (s && s->session_ctx && s->session_ctx->libctx)
+ libctx = s->session_ctx->libctx;
+ else
+ libctx = OSSL_LIB_CTX_get0_global_default();
+
+ if ((nid == NID_sha1 || nid == NID_md5_sha1)
+ && ossl_ctx_legacy_digest_signatures_allowed(libctx, 0)
+ && ((s != NULL && SSL_get_security_level(SSL_CONNECTION_GET_SSL(s)) < 2)
+ || (ctx != NULL && SSL_CTX_get_security_level(ctx) < 2)
+ ))
+ /* When rh-allow-sha1-signatures = yes and security level <= 1,
+ * explicitly allow SHA1 for backwards compatibility. Also allow
+ * MD5-SHA1 because TLS 1.0 is still supported, which uses it. */
+ return 1;
+
if (s != NULL)
return ssl_security(s, op, secbits, nid, x);
else
diff --git a/test/recipes/25-test_verify.t b/test/recipes/25-test_verify.t
index 1c8fce86fd..a584629062 100644
--- a/test/recipes/25-test_verify.t
+++ b/test/recipes/25-test_verify.t
@@ -481,8 +481,8 @@ ok(verify("ee-pss-sha1-cert", "", ["root-cert"], ["ca-cert"], "-auth_level", "0"
ok(verify("ee-pss-sha256-cert", "", ["root-cert"], ["ca-cert"], ),
"CA with PSS signature using SHA256");
-ok(!verify("ee-pss-sha1-cert", "", ["root-cert"], ["ca-cert"], "-auth_level", "1"),
- "Reject PSS signature using SHA1 and auth level 1");
+ok(!verify("ee-pss-sha1-cert", "", ["root-cert"], ["ca-cert"], "-auth_level", "2"),
+ "Reject PSS signature using SHA1 and auth level 2");
ok(verify("ee-pss-sha256-cert", "", ["root-cert"], ["ca-cert"], "-auth_level", "2"),
"PSS signature using SHA256 and auth level 2");
--
2.44.0