From 193b5d769cdaa3bc0778f7b7ae354618097ca61e Mon Sep 17 00:00:00 2001 From: Benjamin Kaduk Date: Thu, 16 Mar 2017 17:17:16 -0500 Subject: [PATCH] Add SSL_early_get1_extensions_present() It is an API to be used from the early callback that indicates what extensions were present in the ClientHello, and in what order. This can be used to eliminate unneeded calls to SSL_early_get0_ext() (which itself scales linearly in the number of extensions supported by the library). Reviewed-by: Matt Caswell (Merged from https://github.com/openssl/openssl/pull/2976) --- doc/man3/SSL_CTX_set_early_cb.pod | 17 +++++++++++++--- include/openssl/ssl.h | 1 + ssl/ssl_lib.c | 32 +++++++++++++++++++++++++++++++ ssl/ssl_locl.h | 2 ++ ssl/statem/extensions.c | 2 ++ util/libssl.num | 1 + 6 files changed, 52 insertions(+), 3 deletions(-) diff --git a/doc/man3/SSL_CTX_set_early_cb.pod b/doc/man3/SSL_CTX_set_early_cb.pod index 771e4ca0a7..c2b4650a06 100644 --- a/doc/man3/SSL_CTX_set_early_cb.pod +++ b/doc/man3/SSL_CTX_set_early_cb.pod @@ -2,7 +2,7 @@ =head1 NAME -SSL_CTX_set_early_cb, SSL_early_cb_fn, SSL_early_isv2, SSL_early_get0_legacy_version, SSL_early_get0_random, SSL_early_get0_session_id, SSL_early_get0_ciphers, SSL_early_get0_compression_methods, SSL_early_get0_ext - callback functions for early server-side ClientHello processing +SSL_CTX_set_early_cb, SSL_early_cb_fn, SSL_early_isv2, SSL_early_get0_legacy_version, SSL_early_get0_random, SSL_early_get0_session_id, SSL_early_get0_ciphers, SSL_early_get0_compression_methods, SSL_early_get1_extensions_present, SSL_early_get0_ext - callback functions for early server-side ClientHello processing =head1 SYNOPSIS @@ -14,6 +14,7 @@ SSL_CTX_set_early_cb, SSL_early_cb_fn, SSL_early_isv2, SSL_early_get0_legacy_ver size_t SSL_early_get0_session_id(SSL *s, const unsigned char **out); size_t SSL_early_get0_ciphers(SSL *s, const unsigned char **out); size_t SSL_early_get0_compression_methods(SSL *s, const unsigned char **out); + int SSL_early_get1_extensions_present(SSL *s, int **out, size_t *outlen); int SSL_early_get0_ext(SSL *s, int type, const unsigned char **out, size_t *outlen); @@ -53,6 +54,14 @@ from the ClientHello on a per-extension basis. For the provided wire protocol extension type value, the extension value and length are returned in the output parameters (if present). +SSL_early_get1_extensions_present() can be used prior to SSL_early_get0_ext(), +to determine which extensions are present in the ClientHello before querying +for them. The B and B parameters are both required, and on +success the caller must release the storage allocated for B<*out> using +OPENSSL_free(). The contents of B<*out> is an array of integers holding the +numerical value of the TLS extension types in the order they appear in the +ClientHello. B<*outlen> contains the number of elements in the array. + =head1 NOTES The early callback provides a vast window of possibilities for application @@ -88,6 +97,8 @@ assumed to be valid. SSL_early_get0_ext() returns 1 if the extension of type 'type' is present, and 0 otherwise. +SSL_early_get1_extensions_present() returns 1 on success and 0 on failure. + =head1 SEE ALSO L, L, @@ -97,8 +108,8 @@ L The SSL early callback, SSL_early_isv2(), SSL_early_get0_random(), SSL_early_get0_session_id(), SSL_early_get0_ciphers(), -SSL_early_get0_compression_methods(), and SSL_early_get0_ext() were -added in OpenSSL 1.1.1. +SSL_early_get0_compression_methods(), SSL_early_get0_ext(), and +SSL_early_get1_extensions_present() were added in OpenSSL 1.1.1. =head1 COPYRIGHT diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h index 0eb41c9574..2b8344956b 100644 --- a/include/openssl/ssl.h +++ b/include/openssl/ssl.h @@ -1682,6 +1682,7 @@ size_t SSL_early_get0_random(SSL *s, const unsigned char **out); size_t SSL_early_get0_session_id(SSL *s, const unsigned char **out); size_t SSL_early_get0_ciphers(SSL *s, const unsigned char **out); size_t SSL_early_get0_compression_methods(SSL *s, const unsigned char **out); +int SSL_early_get1_extensions_present(SSL *s, int **out, size_t *outlen); int SSL_early_get0_ext(SSL *s, unsigned int type, const unsigned char **out, size_t *outlen); diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c index e90c4b8732..068df4200d 100644 --- a/ssl/ssl_lib.c +++ b/ssl/ssl_lib.c @@ -4598,6 +4598,38 @@ size_t SSL_early_get0_compression_methods(SSL *s, const unsigned char **out) return s->clienthello->compressions_len; } +int SSL_early_get1_extensions_present(SSL *s, int **out, size_t *outlen) +{ + RAW_EXTENSION *ext; + int *present; + size_t num = 0, i; + + if (s->clienthello == NULL || out == NULL || outlen == NULL) + return 0; + for (i = 0; i < s->clienthello->pre_proc_exts_len; i++) { + ext = s->clienthello->pre_proc_exts + i; + if (ext->present) + num++; + } + present = OPENSSL_malloc(sizeof(*present) * num); + if (present == NULL) + return 0; + for (i = 0; i < s->clienthello->pre_proc_exts_len; i++) { + ext = s->clienthello->pre_proc_exts + i; + if (ext->present) { + if (ext->received_order >= num) + goto err; + present[ext->received_order] = ext->type; + } + } + *out = present; + *outlen = num; + return 1; + err: + OPENSSL_free(present); + return 0; +} + int SSL_early_get0_ext(SSL *s, unsigned int type, const unsigned char **out, size_t *outlen) { diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h index fe6119b2ff..85944ecfe7 100644 --- a/ssl/ssl_locl.h +++ b/ssl/ssl_locl.h @@ -668,6 +668,8 @@ typedef struct raw_extension_st { int parsed; /* The type of this extension, i.e. a TLSEXT_TYPE_* value */ unsigned int type; + /* Track what order extensions are received in (0-based). */ + size_t received_order; } RAW_EXTENSION; typedef struct { diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c index b4d85d958c..d40c34cd1c 100644 --- a/ssl/statem/extensions.c +++ b/ssl/statem/extensions.c @@ -462,6 +462,7 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context, return 0; } + i = 0; while (PACKET_remaining(&extensions) > 0) { unsigned int type, idx; PACKET extension; @@ -518,6 +519,7 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context, thisex->data = extension; thisex->present = 1; thisex->type = type; + thisex->received_order = i++; } } diff --git a/util/libssl.num b/util/libssl.num index b4acb5db35..4cf8227b73 100644 --- a/util/libssl.num +++ b/util/libssl.num @@ -450,3 +450,4 @@ SSL_set_block_padding 450 1_1_1 EXIST::FUNCTION: SSL_set_record_padding_callback_arg 451 1_1_1 EXIST::FUNCTION: SSL_CTX_set_record_padding_callback_arg 452 1_1_1 EXIST::FUNCTION: SSL_CTX_use_serverinfo_ex 453 1_1_1 EXIST::FUNCTION: +SSL_early_get1_extensions_present 454 1_1_1 EXIST::FUNCTION: