diff options
Diffstat (limited to 'src/libgit2/streams/openssl.c')
| -rw-r--r-- | src/libgit2/streams/openssl.c | 747 |
1 files changed, 747 insertions, 0 deletions
diff --git a/src/libgit2/streams/openssl.c b/src/libgit2/streams/openssl.c new file mode 100644 index 000000000..89c96780c --- /dev/null +++ b/src/libgit2/streams/openssl.c @@ -0,0 +1,747 @@ +/* + * Copyright (C) the libgit2 contributors. All rights reserved. + * + * This file is part of libgit2, distributed under the GNU GPL v2 with + * a Linking Exception. For full terms see the included COPYING file. + */ + +#include "streams/openssl.h" +#include "streams/openssl_legacy.h" +#include "streams/openssl_dynamic.h" + +#ifdef GIT_OPENSSL + +#include <ctype.h> + +#include "common.h" +#include "runtime.h" +#include "settings.h" +#include "posix.h" +#include "stream.h" +#include "streams/socket.h" +#include "netops.h" +#include "git2/transport.h" +#include "git2/sys/openssl.h" + +#ifndef GIT_WIN32 +# include <sys/types.h> +# include <sys/socket.h> +# include <netinet/in.h> +#endif + +#ifndef GIT_OPENSSL_DYNAMIC +# include <openssl/ssl.h> +# include <openssl/err.h> +# include <openssl/x509v3.h> +# include <openssl/bio.h> +#endif + +SSL_CTX *git__ssl_ctx; + +#define GIT_SSL_DEFAULT_CIPHERS "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-DSS-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA:DHE-DSS-AES128-SHA256:DHE-DSS-AES256-SHA256:DHE-DSS-AES128-SHA:DHE-DSS-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA" + + +static BIO_METHOD *git_stream_bio_method; +static int init_bio_method(void); + +/** + * This function aims to clean-up the SSL context which + * we allocated. + */ +static void shutdown_ssl(void) +{ + if (git_stream_bio_method) { + BIO_meth_free(git_stream_bio_method); + git_stream_bio_method = NULL; + } + + if (git__ssl_ctx) { + SSL_CTX_free(git__ssl_ctx); + git__ssl_ctx = NULL; + } +} + +#ifdef VALGRIND +# if !defined(GIT_OPENSSL_LEGACY) && !defined(GIT_OPENSSL_DYNAMIC) + +static void *git_openssl_malloc(size_t bytes, const char *file, int line) +{ + GIT_UNUSED(file); + GIT_UNUSED(line); + return git__calloc(1, bytes); +} + +static void *git_openssl_realloc(void *mem, size_t size, const char *file, int line) +{ + GIT_UNUSED(file); + GIT_UNUSED(line); + return git__realloc(mem, size); +} + +static void git_openssl_free(void *mem, const char *file, int line) +{ + GIT_UNUSED(file); + GIT_UNUSED(line); + git__free(mem); +} +# else /* !GIT_OPENSSL_LEGACY && !GIT_OPENSSL_DYNAMIC */ +static void *git_openssl_malloc(size_t bytes) +{ + return git__calloc(1, bytes); +} + +static void *git_openssl_realloc(void *mem, size_t size) +{ + return git__realloc(mem, size); +} + +static void git_openssl_free(void *mem) +{ + git__free(mem); +} +# endif /* !GIT_OPENSSL_LEGACY && !GIT_OPENSSL_DYNAMIC */ +#endif /* VALGRIND */ + +static int openssl_init(void) +{ + long ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3; + const char *ciphers = git_libgit2__ssl_ciphers(); +#ifdef VALGRIND + static bool allocators_initialized = false; +#endif + + /* Older OpenSSL and MacOS OpenSSL doesn't have this */ +#ifdef SSL_OP_NO_COMPRESSION + ssl_opts |= SSL_OP_NO_COMPRESSION; +#endif + +#ifdef VALGRIND + /* + * Swap in our own allocator functions that initialize + * allocated memory to avoid spurious valgrind warnings. + * Don't error on failure; many builds of OpenSSL do not + * allow you to set these functions. + */ + if (!allocators_initialized) { + CRYPTO_set_mem_functions(git_openssl_malloc, + git_openssl_realloc, + git_openssl_free); + allocators_initialized = true; + } +#endif + + OPENSSL_init_ssl(0, NULL); + + /* + * Load SSLv{2,3} and TLSv1 so that we can talk with servers + * which use the SSL hellos, which are often used for + * compatibility. We then disable SSL so we only allow OpenSSL + * to speak TLSv1 to perform the encryption itself. + */ + if (!(git__ssl_ctx = SSL_CTX_new(SSLv23_method()))) + goto error; + + SSL_CTX_set_options(git__ssl_ctx, ssl_opts); + SSL_CTX_set_mode(git__ssl_ctx, SSL_MODE_AUTO_RETRY); + SSL_CTX_set_verify(git__ssl_ctx, SSL_VERIFY_NONE, NULL); + if (!SSL_CTX_set_default_verify_paths(git__ssl_ctx)) + goto error; + + if (!ciphers) + ciphers = GIT_SSL_DEFAULT_CIPHERS; + + if(!SSL_CTX_set_cipher_list(git__ssl_ctx, ciphers)) + goto error; + + if (init_bio_method() < 0) + goto error; + + return git_runtime_shutdown_register(shutdown_ssl); + +error: + git_error_set(GIT_ERROR_NET, "could not initialize openssl: %s", + ERR_error_string(ERR_get_error(), NULL)); + SSL_CTX_free(git__ssl_ctx); + git__ssl_ctx = NULL; + return -1; +} + +/* + * When we use dynamic loading, we defer OpenSSL initialization until + * it's first used. `openssl_ensure_initialized` will do the work + * under a mutex. + */ +git_mutex openssl_mutex; +bool openssl_initialized; + +int git_openssl_stream_global_init(void) +{ +#ifndef GIT_OPENSSL_DYNAMIC + return openssl_init(); +#else + if (git_mutex_init(&openssl_mutex) != 0) + return -1; + + return 0; +#endif +} + +static int openssl_ensure_initialized(void) +{ +#ifdef GIT_OPENSSL_DYNAMIC + int error = 0; + + if (git_mutex_lock(&openssl_mutex) != 0) + return -1; + + if (!openssl_initialized) { + if ((error = git_openssl_stream_dynamic_init()) == 0) + error = openssl_init(); + + openssl_initialized = true; + } + + error |= git_mutex_unlock(&openssl_mutex); + return error; + +#else + return 0; +#endif +} + +#if !defined(GIT_OPENSSL_LEGACY) && !defined(GIT_OPENSSL_DYNAMIC) +int git_openssl_set_locking(void) +{ +# ifdef GIT_THREADS + return 0; +# else + git_error_set(GIT_ERROR_THREAD, "libgit2 was not built with threads"); + return -1; +# endif +} +#endif + + +static int bio_create(BIO *b) +{ + BIO_set_init(b, 1); + BIO_set_data(b, NULL); + + return 1; +} + +static int bio_destroy(BIO *b) +{ + if (!b) + return 0; + + BIO_set_data(b, NULL); + + return 1; +} + +static int bio_read(BIO *b, char *buf, int len) +{ + git_stream *io = (git_stream *) BIO_get_data(b); + + return (int) git_stream_read(io, buf, len); +} + +static int bio_write(BIO *b, const char *buf, int len) +{ + git_stream *io = (git_stream *) BIO_get_data(b); + return (int) git_stream_write(io, buf, len, 0); +} + +static long bio_ctrl(BIO *b, int cmd, long num, void *ptr) +{ + GIT_UNUSED(b); + GIT_UNUSED(num); + GIT_UNUSED(ptr); + + if (cmd == BIO_CTRL_FLUSH) + return 1; + + return 0; +} + +static int bio_gets(BIO *b, char *buf, int len) +{ + GIT_UNUSED(b); + GIT_UNUSED(buf); + GIT_UNUSED(len); + return -1; +} + +static int bio_puts(BIO *b, const char *str) +{ + return bio_write(b, str, strlen(str)); +} + +static int init_bio_method(void) +{ + /* Set up the BIO_METHOD we use for wrapping our own stream implementations */ + git_stream_bio_method = BIO_meth_new(BIO_TYPE_SOURCE_SINK | BIO_get_new_index(), "git_stream"); + GIT_ERROR_CHECK_ALLOC(git_stream_bio_method); + + BIO_meth_set_write(git_stream_bio_method, bio_write); + BIO_meth_set_read(git_stream_bio_method, bio_read); + BIO_meth_set_puts(git_stream_bio_method, bio_puts); + BIO_meth_set_gets(git_stream_bio_method, bio_gets); + BIO_meth_set_ctrl(git_stream_bio_method, bio_ctrl); + BIO_meth_set_create(git_stream_bio_method, bio_create); + BIO_meth_set_destroy(git_stream_bio_method, bio_destroy); + + return 0; +} + +static int ssl_set_error(SSL *ssl, int error) +{ + int err; + unsigned long e; + + err = SSL_get_error(ssl, error); + + GIT_ASSERT(err != SSL_ERROR_WANT_READ); + GIT_ASSERT(err != SSL_ERROR_WANT_WRITE); + + switch (err) { + case SSL_ERROR_WANT_CONNECT: + case SSL_ERROR_WANT_ACCEPT: + git_error_set(GIT_ERROR_SSL, "SSL error: connection failure"); + break; + case SSL_ERROR_WANT_X509_LOOKUP: + git_error_set(GIT_ERROR_SSL, "SSL error: x509 error"); + break; + case SSL_ERROR_SYSCALL: + e = ERR_get_error(); + if (e > 0) { + char errmsg[256]; + ERR_error_string_n(e, errmsg, sizeof(errmsg)); + git_error_set(GIT_ERROR_NET, "SSL error: %s", errmsg); + break; + } else if (error < 0) { + git_error_set(GIT_ERROR_OS, "SSL error: syscall failure"); + break; + } + git_error_set(GIT_ERROR_SSL, "SSL error: received early EOF"); + return GIT_EEOF; + break; + case SSL_ERROR_SSL: + { + char errmsg[256]; + e = ERR_get_error(); + ERR_error_string_n(e, errmsg, sizeof(errmsg)); + git_error_set(GIT_ERROR_SSL, "SSL error: %s", errmsg); + break; + } + case SSL_ERROR_NONE: + case SSL_ERROR_ZERO_RETURN: + default: + git_error_set(GIT_ERROR_SSL, "SSL error: unknown error"); + break; + } + return -1; +} + +static int ssl_teardown(SSL *ssl) +{ + int ret; + + ret = SSL_shutdown(ssl); + if (ret < 0) + ret = ssl_set_error(ssl, ret); + else + ret = 0; + + return ret; +} + +static int check_host_name(const char *name, const char *host) +{ + if (!strcasecmp(name, host)) + return 0; + + if (gitno__match_host(name, host) < 0) + return -1; + + return 0; +} + +static int verify_server_cert(SSL *ssl, const char *host) +{ + X509 *cert = NULL; + X509_NAME *peer_name; + ASN1_STRING *str; + unsigned char *peer_cn = NULL; + int matched = -1, type = GEN_DNS; + GENERAL_NAMES *alts; + struct in6_addr addr6; + struct in_addr addr4; + void *addr = NULL; + int i = -1, j, error = 0; + + if (SSL_get_verify_result(ssl) != X509_V_OK) { + git_error_set(GIT_ERROR_SSL, "the SSL certificate is invalid"); + return GIT_ECERTIFICATE; + } + + /* Try to parse the host as an IP address to see if it is */ + if (p_inet_pton(AF_INET, host, &addr4)) { + type = GEN_IPADD; + addr = &addr4; + } else { + if (p_inet_pton(AF_INET6, host, &addr6)) { + type = GEN_IPADD; + addr = &addr6; + } + } + + + cert = SSL_get_peer_certificate(ssl); + if (!cert) { + error = -1; + git_error_set(GIT_ERROR_SSL, "the server did not provide a certificate"); + goto cleanup; + } + + /* Check the alternative names */ + alts = X509_get_ext_d2i(cert, NID_subject_alt_name, NULL, NULL); + if (alts) { + int num; + + num = sk_GENERAL_NAME_num(alts); + for (i = 0; i < num && matched != 1; i++) { + const GENERAL_NAME *gn = sk_GENERAL_NAME_value(alts, i); + const char *name = (char *) ASN1_STRING_get0_data(gn->d.ia5); + size_t namelen = (size_t) ASN1_STRING_length(gn->d.ia5); + + /* Skip any names of a type we're not looking for */ + if (gn->type != type) + continue; + + if (type == GEN_DNS) { + /* If it contains embedded NULs, don't even try */ + if (memchr(name, '\0', namelen)) + continue; + + if (check_host_name(name, host) < 0) + matched = 0; + else + matched = 1; + } else if (type == GEN_IPADD) { + /* Here name isn't so much a name but a binary representation of the IP */ + matched = addr && !!memcmp(name, addr, namelen); + } + } + } + GENERAL_NAMES_free(alts); + + if (matched == 0) + goto cert_fail_name; + + if (matched == 1) { + goto cleanup; + } + + /* If no alternative names are available, check the common name */ + peer_name = X509_get_subject_name(cert); + if (peer_name == NULL) + goto on_error; + + if (peer_name) { + /* Get the index of the last CN entry */ + while ((j = X509_NAME_get_index_by_NID(peer_name, NID_commonName, i)) >= 0) + i = j; + } + + if (i < 0) + goto on_error; + + str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(peer_name, i)); + if (str == NULL) + goto on_error; + + /* Work around a bug in OpenSSL whereby ASN1_STRING_to_UTF8 fails if it's already in utf-8 */ + if (ASN1_STRING_type(str) == V_ASN1_UTF8STRING) { + int size = ASN1_STRING_length(str); + + if (size > 0) { + peer_cn = OPENSSL_malloc(size + 1); + GIT_ERROR_CHECK_ALLOC(peer_cn); + memcpy(peer_cn, ASN1_STRING_get0_data(str), size); + peer_cn[size] = '\0'; + } else { + goto cert_fail_name; + } + } else { + int size = ASN1_STRING_to_UTF8(&peer_cn, str); + GIT_ERROR_CHECK_ALLOC(peer_cn); + if (memchr(peer_cn, '\0', size)) + goto cert_fail_name; + } + + if (check_host_name((char *)peer_cn, host) < 0) + goto cert_fail_name; + + goto cleanup; + +cert_fail_name: + error = GIT_ECERTIFICATE; + git_error_set(GIT_ERROR_SSL, "hostname does not match certificate"); + goto cleanup; + +on_error: + error = ssl_set_error(ssl, 0); + goto cleanup; + +cleanup: + X509_free(cert); + OPENSSL_free(peer_cn); + return error; +} + +typedef struct { + git_stream parent; + git_stream *io; + int owned; + bool connected; + char *host; + SSL *ssl; + git_cert_x509 cert_info; +} openssl_stream; + +static int openssl_connect(git_stream *stream) +{ + int ret; + BIO *bio; + openssl_stream *st = (openssl_stream *) stream; + + if (st->owned && (ret = git_stream_connect(st->io)) < 0) + return ret; + + bio = BIO_new(git_stream_bio_method); + GIT_ERROR_CHECK_ALLOC(bio); + + BIO_set_data(bio, st->io); + SSL_set_bio(st->ssl, bio, bio); + + /* specify the host in case SNI is needed */ +#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME + SSL_set_tlsext_host_name(st->ssl, st->host); +#endif + + if ((ret = SSL_connect(st->ssl)) <= 0) + return ssl_set_error(st->ssl, ret); + + st->connected = true; + + return verify_server_cert(st->ssl, st->host); +} + +static int openssl_certificate(git_cert **out, git_stream *stream) +{ + openssl_stream *st = (openssl_stream *) stream; + X509 *cert = SSL_get_peer_certificate(st->ssl); + unsigned char *guard, *encoded_cert = NULL; + int error, len; + + /* Retrieve the length of the certificate first */ + len = i2d_X509(cert, NULL); + if (len < 0) { + git_error_set(GIT_ERROR_NET, "failed to retrieve certificate information"); + error = -1; + goto out; + } + + encoded_cert = git__malloc(len); + GIT_ERROR_CHECK_ALLOC(encoded_cert); + /* i2d_X509 makes 'guard' point to just after the data */ + guard = encoded_cert; + + len = i2d_X509(cert, &guard); + if (len < 0) { + git_error_set(GIT_ERROR_NET, "failed to retrieve certificate information"); + error = -1; + goto out; + } + + st->cert_info.parent.cert_type = GIT_CERT_X509; + st->cert_info.data = encoded_cert; + st->cert_info.len = len; + encoded_cert = NULL; + + *out = &st->cert_info.parent; + error = 0; + +out: + git__free(encoded_cert); + X509_free(cert); + return error; +} + +static int openssl_set_proxy(git_stream *stream, const git_proxy_options *proxy_opts) +{ + openssl_stream *st = (openssl_stream *) stream; + + return git_stream_set_proxy(st->io, proxy_opts); +} + +static ssize_t openssl_write(git_stream *stream, const char *data, size_t data_len, int flags) +{ + openssl_stream *st = (openssl_stream *) stream; + int ret, len = min(data_len, INT_MAX); + + GIT_UNUSED(flags); + + if ((ret = SSL_write(st->ssl, data, len)) <= 0) + return ssl_set_error(st->ssl, ret); + + return ret; +} + +static ssize_t openssl_read(git_stream *stream, void *data, size_t len) +{ + openssl_stream *st = (openssl_stream *) stream; + int ret; + + if ((ret = SSL_read(st->ssl, data, len)) <= 0) + return ssl_set_error(st->ssl, ret); + + return ret; +} + +static int openssl_close(git_stream *stream) +{ + openssl_stream *st = (openssl_stream *) stream; + int ret; + + if (st->connected && (ret = ssl_teardown(st->ssl)) < 0) + return -1; + + st->connected = false; + + return st->owned ? git_stream_close(st->io) : 0; +} + +static void openssl_free(git_stream *stream) +{ + openssl_stream *st = (openssl_stream *) stream; + + if (st->owned) + git_stream_free(st->io); + + SSL_free(st->ssl); + git__free(st->host); + git__free(st->cert_info.data); + git__free(st); +} + +static int openssl_stream_wrap( + git_stream **out, + git_stream *in, + const char *host, + int owned) +{ + openssl_stream *st; + + GIT_ASSERT_ARG(out); + GIT_ASSERT_ARG(in); + GIT_ASSERT_ARG(host); + + st = git__calloc(1, sizeof(openssl_stream)); + GIT_ERROR_CHECK_ALLOC(st); + + st->io = in; + st->owned = owned; + + st->ssl = SSL_new(git__ssl_ctx); + if (st->ssl == NULL) { + git_error_set(GIT_ERROR_SSL, "failed to create ssl object"); + git__free(st); + return -1; + } + + st->host = git__strdup(host); + GIT_ERROR_CHECK_ALLOC(st->host); + + st->parent.version = GIT_STREAM_VERSION; + st->parent.encrypted = 1; + st->parent.proxy_support = git_stream_supports_proxy(st->io); + st->parent.connect = openssl_connect; + st->parent.certificate = openssl_certificate; + st->parent.set_proxy = openssl_set_proxy; + st->parent.read = openssl_read; + st->parent.write = openssl_write; + st->parent.close = openssl_close; + st->parent.free = openssl_free; + + *out = (git_stream *) st; + return 0; +} + +int git_openssl_stream_wrap(git_stream **out, git_stream *in, const char *host) +{ + if (openssl_ensure_initialized() < 0) + return -1; + + return openssl_stream_wrap(out, in, host, 0); +} + +int git_openssl_stream_new(git_stream **out, const char *host, const char *port) +{ + git_stream *stream = NULL; + int error; + + GIT_ASSERT_ARG(out); + GIT_ASSERT_ARG(host); + GIT_ASSERT_ARG(port); + + if (openssl_ensure_initialized() < 0) + return -1; + + if ((error = git_socket_stream_new(&stream, host, port)) < 0) + return error; + + if ((error = openssl_stream_wrap(out, stream, host, 1)) < 0) { + git_stream_close(stream); + git_stream_free(stream); + } + + return error; +} + +int git_openssl__set_cert_location(const char *file, const char *path) +{ + if (openssl_ensure_initialized() < 0) + return -1; + + if (SSL_CTX_load_verify_locations(git__ssl_ctx, file, path) == 0) { + char errmsg[256]; + + ERR_error_string_n(ERR_get_error(), errmsg, sizeof(errmsg)); + git_error_set(GIT_ERROR_SSL, "OpenSSL error: failed to load certificates: %s", + errmsg); + + return -1; + } + return 0; +} + +#else + +#include "stream.h" +#include "git2/sys/openssl.h" + +int git_openssl_stream_global_init(void) +{ + return 0; +} + +int git_openssl_set_locking(void) +{ + git_error_set(GIT_ERROR_SSL, "libgit2 was not built with OpenSSL support"); + return -1; +} + +#endif |