Clarify that sigalg configuration does not impact TLS 1.0/1.1
I always have to double-check the code for which way we went on this.
Change-Id: I090f16b832328a80c8e007de6775797a495e3b6d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/76188
Commit-Queue: Bob Beck <bbe@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 6a074b5..b9bf7ea 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -1147,17 +1147,29 @@
OPENSSL_EXPORT int SSL_is_signature_algorithm_rsa_pss(uint16_t sigalg);
// SSL_CTX_set_signing_algorithm_prefs configures |ctx| to use |prefs| as the
-// preference list when signing with |ctx|'s private key. It returns one on
-// success and zero on error. |prefs| should not include the internal-only value
-// |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+// preference list when signing with |ctx|'s private key in TLS 1.2 and up. It
+// returns one on success and zero on error. |prefs| should not include the
+// internal-only TLS 1.0 value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+//
+// This setting is not used in TLS 1.0 and 1.1. Those protocols always sign a
+// hardcoded algorithm (an MD5/SHA-1 concatenation for RSA, and SHA-1 for
+// ECDSA). BoringSSL will use those algorithms if and only if those versions are
+// used. To disable them, set the minimum version to TLS 1.2 (default) or
+// higher.
OPENSSL_EXPORT int SSL_CTX_set_signing_algorithm_prefs(SSL_CTX *ctx,
const uint16_t *prefs,
size_t num_prefs);
// SSL_set_signing_algorithm_prefs configures |ssl| to use |prefs| as the
-// preference list when signing with |ssl|'s private key. It returns one on
-// success and zero on error. |prefs| should not include the internal-only value
-// |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+// preference list when signing with |ssl|'s private key in TLS 1.2 and up. It
+// returns one on success and zero on error. |prefs| should not include the
+// internal-only TLS 1.0 value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+//
+// This setting is not used in TLS 1.0 and 1.1. Those protocols always sign a
+// hardcoded algorithm (an MD5/SHA-1 concatenation for RSA, and SHA-1 for
+// ECDSA). BoringSSL will use those algorithms if and only if those versions are
+// used. To disable them, set the minimum version to TLS 1.2 (default) or
+// higher.
OPENSSL_EXPORT int SSL_set_signing_algorithm_prefs(SSL *ssl,
const uint16_t *prefs,
size_t num_prefs);
@@ -2847,17 +2859,29 @@
OPENSSL_EXPORT int SSL_set1_verify_cert_store(SSL *ssl, X509_STORE *store);
// SSL_CTX_set_verify_algorithm_prefs configures |ctx| to use |prefs| as the
-// preference list when verifying signatures from the peer's long-term key. It
-// returns one on zero on error. |prefs| should not include the internal-only
-// value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+// preference list when verifying signatures from the peer's long-term key in
+// TLS 1.2 and up. It returns one on zero on error. |prefs| should not include
+// the internal-only TLS 1.0 value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+//
+// This setting is not used in TLS 1.0 and 1.1. Those protocols always sign a
+// hardcoded algorithm (an MD5/SHA-1 concatenation for RSA, and SHA-1 for
+// ECDSA). BoringSSL will accept those algorithms if and only if those versions
+// are used. To disable them, set the minimum version to TLS 1.2 (default) or
+// higher.
OPENSSL_EXPORT int SSL_CTX_set_verify_algorithm_prefs(SSL_CTX *ctx,
const uint16_t *prefs,
size_t num_prefs);
// SSL_set_verify_algorithm_prefs configures |ssl| to use |prefs| as the
-// preference list when verifying signatures from the peer's long-term key. It
-// returns one on zero on error. |prefs| should not include the internal-only
-// value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+// preference list when verifying signatures from the peer's long-term key in
+// TLS 1.2 and up. It returns one on zero on error. |prefs| should not include
+// the internal-only TLS 1.0 value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+//
+// This setting is not used in TLS 1.0 and 1.1. Those protocols always sign a
+// hardcoded algorithm (an MD5/SHA-1 concatenation for RSA, and SHA-1 for
+// ECDSA). BoringSSL will accept those algorithms if and only if those versions
+// are used. To disable them, set the minimum version to TLS 1.2 (default) or
+// higher.
OPENSSL_EXPORT int SSL_set_verify_algorithm_prefs(SSL *ssl,
const uint16_t *prefs,
size_t num_prefs);
