fix(sync): patch the mbedtls stream double-free that reset the chip

Upstream libgit2 v1.9.4 bug: mbedtls_stream_wrap's ssl_setup error
path closes and frees the caller's socket stream, then
git_mbedtls_stream_new frees it again — and wrap's other error paths
don't free it at all, so callers can't compensate either way. When
ssl_setup failed on the device (internal-RAM exhaustion during the
first real-repo push), the double git__free tripped tlsf ("block
already marked as free") and reset the chip mid-:sync.

Fixed the way esp_map.c replaces map.c: the vendored streams/mbedtls.c
is excluded from the component and esp_mbedtls_stream.c (verbatim copy
+ one-hunk fix: out_err leaves st->io to the caller, and frees the
leaked ssl struct) takes its place. Keep the copy in lockstep on
submodule bumps; worth reporting upstream.
This commit is contained in:
Julien Calixte
2026-07-13 10:25:12 +02:00
parent 2660a3e9dd
commit af5b41a104
2 changed files with 505 additions and 0 deletions

View File

@@ -41,6 +41,12 @@ file(GLOB LG2_SRCS
"${LG2}/deps/pcre/*.c"
"${LG2}/deps/zlib/*.c"
)
# streams/mbedtls.c is replaced by our patched copy: its wrap() error path
# double-freed the socket stream (tlsf abort on device when ssl_setup failed
# under memory pressure). See esp_mbedtls_stream.c's header for the one-hunk
# delta; keep the copy in lockstep on submodule bumps.
list(REMOVE_ITEM LG2_SRCS "${LG2}/src/libgit2/streams/mbedtls.c")
list(APPEND LG2_SRCS
"${LG2}/src/util/allocators/failalloc.c"
"${LG2}/src/util/allocators/stdalloc.c"
@@ -48,6 +54,7 @@ list(APPEND LG2_SRCS
"${LG2}/src/util/hash/mbedtls.c" # SHA1 + SHA256 via mbedtls
"${CMAKE_CURRENT_LIST_DIR}/esp_map.c" # p_mmap via malloc+read (no <sys/mman.h>)
"${CMAKE_CURRENT_LIST_DIR}/esp_stubs.c" # getuid/readlink/utimes/... stubs
"${CMAKE_CURRENT_LIST_DIR}/esp_mbedtls_stream.c" # streams/mbedtls.c + double-free fix
# NOTE: unix/map.c replaced by esp_map.c — picolibc has no <sys/mman.h>.
# NOTE: unix/process.c deliberately excluded — needs fork()/sys/wait.h,
# only used by the SSH-exec transport we don't enable.

View File

@@ -0,0 +1,498 @@
/*
* 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.
*/
/*
* esp_mbedtls_stream.c — verbatim copy of the vendored
* src/libgit2/streams/mbedtls.c (v1.9.4) with ONE fix; it replaces the
* vendored file in CMakeLists.txt (same pattern as esp_map.c).
*
* THE FIX (2026-07-13): mbedtls_stream_wrap()'s `out_err` path closed and
* freed `st->io` — the caller's socket stream — but every caller frees that
* stream on error too (git_mbedtls_stream_new does close+free right after),
* and wrap's OTHER error paths (calloc/strdup failures) do NOT free it, so
* the caller cannot compensate either way. When mbedtls_ssl_setup failed on
* the device (internal-RAM exhaustion during the first real-repo push), the
* double git__free tripped tlsf ("block already marked as free") and reset
* the chip instead of surfacing a clean error. Delta from vendor: the
* `out_err` label no longer touches st->io — on error, ownership of `in`
* stays with the caller, consistently — and it frees the git__malloc'd
* st->ssl struct the vendored path leaked.
*
* Keep this file in lockstep with the vendored one on submodule bumps (diff
* against it; the delta must stay this one hunk).
*/
#include "streams/mbedtls.h"
#ifdef GIT_MBEDTLS
#include <ctype.h>
#include "runtime.h"
#include "stream.h"
#include "streams/socket.h"
#include "git2/transport.h"
#include "util.h"
#ifndef GIT_DEFAULT_CERT_LOCATION
#define GIT_DEFAULT_CERT_LOCATION NULL
#endif
/* Work around C90-conformance issues */
#if !defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L)
# if defined(_MSC_VER)
# define inline __inline
# elif defined(__GNUC__)
# define inline __inline__
# else
# define inline
# endif
#endif
#include <mbedtls/ssl.h>
#include <mbedtls/error.h>
#include <mbedtls/entropy.h>
#include <mbedtls/ctr_drbg.h>
#undef inline
#define GIT_SSL_DEFAULT_CIPHERS "TLS1-3-AES-128-GCM-SHA256:TLS1-3-AES-256-GCM-SHA384:TLS1-3-CHACHA20-POLY1305-SHA256:TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256:TLS-ECDHE-RSA-WITH-AES-128-GCM-SHA256:TLS-ECDHE-ECDSA-WITH-AES-256-GCM-SHA384:TLS-ECDHE-RSA-WITH-AES-256-GCM-SHA384:TLS-ECDHE-ECDSA-WITH-CHACHA20-POLY1305-SHA256:TLS-ECDHE-RSA-WITH-CHACHA20-POLY1305-SHA256:TLS-DHE-RSA-WITH-AES-128-GCM-SHA256:TLS-DHE-RSA-WITH-AES-256-GCM-SHA384:TLS-DHE-RSA-WITH-CHACHA20-POLY1305-SHA256:TLS-ECDHE-ECDSA-WITH-AES-128-CBC-SHA256:TLS-ECDHE-RSA-WITH-AES-128-CBC-SHA256:TLS-ECDHE-ECDSA-WITH-AES-128-CBC-SHA:TLS-ECDHE-RSA-WITH-AES-128-CBC-SHA:TLS-ECDHE-ECDSA-WITH-AES-256-CBC-SHA384:TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384:TLS-ECDHE-ECDSA-WITH-AES-256-CBC-SHA:TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA:TLS-DHE-RSA-WITH-AES-128-CBC-SHA256:TLS-DHE-RSA-WITH-AES-256-CBC-SHA256:TLS-RSA-WITH-AES-128-GCM-SHA256:TLS-RSA-WITH-AES-256-GCM-SHA384:TLS-RSA-WITH-AES-128-CBC-SHA256:TLS-RSA-WITH-AES-256-CBC-SHA256:TLS-RSA-WITH-AES-128-CBC-SHA:TLS-RSA-WITH-AES-256-CBC-SHA"
#define GIT_SSL_DEFAULT_CIPHERS_COUNT 28
static int ciphers_list[GIT_SSL_DEFAULT_CIPHERS_COUNT];
static bool initialized = false;
static mbedtls_ssl_config mbedtls_config;
static mbedtls_ctr_drbg_context mbedtls_rng;
static mbedtls_entropy_context mbedtls_entropy;
static bool has_ca_chain = false;
static mbedtls_x509_crt mbedtls_ca_chain;
/**
* This function aims to clean-up the SSL context which
* we allocated.
*/
static void shutdown_ssl(void)
{
if (has_ca_chain) {
mbedtls_x509_crt_free(&mbedtls_ca_chain);
has_ca_chain = false;
}
if (initialized) {
mbedtls_ctr_drbg_free(&mbedtls_rng);
mbedtls_ssl_config_free(&mbedtls_config);
mbedtls_entropy_free(&mbedtls_entropy);
initialized = false;
}
}
int git_mbedtls_stream_global_init(void)
{
int loaded = 0;
char *crtpath = GIT_DEFAULT_CERT_LOCATION;
struct stat statbuf;
size_t ciphers_known = 0;
char *cipher_name = NULL;
char *cipher_string = NULL;
char *cipher_string_tmp = NULL;
mbedtls_ssl_config_init(&mbedtls_config);
mbedtls_entropy_init(&mbedtls_entropy);
mbedtls_ctr_drbg_init(&mbedtls_rng);
if (mbedtls_ssl_config_defaults(&mbedtls_config,
MBEDTLS_SSL_IS_CLIENT,
MBEDTLS_SSL_TRANSPORT_STREAM,
MBEDTLS_SSL_PRESET_DEFAULT) != 0) {
git_error_set(GIT_ERROR_SSL, "failed to initialize mbedTLS");
goto cleanup;
}
/* configure TLSv1.1 or better */
#ifdef MBEDTLS_SSL_MINOR_VERSION_2
mbedtls_ssl_conf_min_version(&mbedtls_config, MBEDTLS_SSL_MAJOR_VERSION_3, MBEDTLS_SSL_MINOR_VERSION_2);
#endif
/* verify_server_cert is responsible for making the check.
* OPTIONAL because REQUIRED drops the certificate as soon as the check
* is made, so we can never see the certificate and override it. */
mbedtls_ssl_conf_authmode(&mbedtls_config, MBEDTLS_SSL_VERIFY_OPTIONAL);
/* set the list of allowed ciphersuites */
ciphers_known = 0;
cipher_string = cipher_string_tmp = git__strdup(GIT_SSL_DEFAULT_CIPHERS);
GIT_ERROR_CHECK_ALLOC(cipher_string);
while ((cipher_name = git__strtok(&cipher_string_tmp, ":")) != NULL) {
int cipherid = mbedtls_ssl_get_ciphersuite_id(cipher_name);
if (cipherid == 0) continue;
if (ciphers_known >= ARRAY_SIZE(ciphers_list)) {
git_error_set(GIT_ERROR_SSL, "out of cipher list space");
goto cleanup;
}
ciphers_list[ciphers_known++] = cipherid;
}
git__free(cipher_string);
if (!ciphers_known) {
git_error_set(GIT_ERROR_SSL, "no cipher could be enabled");
goto cleanup;
}
mbedtls_ssl_conf_ciphersuites(&mbedtls_config, ciphers_list);
/* Seeding the random number generator */
if (mbedtls_ctr_drbg_seed(&mbedtls_rng, mbedtls_entropy_func,
&mbedtls_entropy, NULL, 0) != 0) {
git_error_set(GIT_ERROR_SSL, "failed to initialize mbedTLS entropy pool");
goto cleanup;
}
mbedtls_ssl_conf_rng(&mbedtls_config, mbedtls_ctr_drbg_random, &mbedtls_rng);
/* load default certificates */
if (crtpath != NULL && stat(crtpath, &statbuf) == 0 && S_ISREG(statbuf.st_mode))
loaded = (git_mbedtls__set_cert_location(crtpath, NULL) == 0);
if (!loaded && crtpath != NULL && stat(crtpath, &statbuf) == 0 && S_ISDIR(statbuf.st_mode))
loaded = (git_mbedtls__set_cert_location(NULL, crtpath) == 0);
initialized = true;
return git_runtime_shutdown_register(shutdown_ssl);
cleanup:
mbedtls_ctr_drbg_free(&mbedtls_rng);
mbedtls_ssl_config_free(&mbedtls_config);
mbedtls_entropy_free(&mbedtls_entropy);
return -1;
}
static int bio_read(void *b, unsigned char *buf, size_t len)
{
git_stream *io = (git_stream *) b;
return (int) git_stream_read(io, buf, min(len, INT_MAX));
}
static int bio_write(void *b, const unsigned char *buf, size_t len)
{
git_stream *io = (git_stream *) b;
return (int) git_stream_write(io, (const char *)buf, min(len, INT_MAX), 0);
}
static int ssl_set_error(mbedtls_ssl_context *ssl, int error)
{
char errbuf[512];
int ret = -1;
GIT_ASSERT(error != MBEDTLS_ERR_SSL_WANT_READ);
GIT_ASSERT(error != MBEDTLS_ERR_SSL_WANT_WRITE);
if (error != 0)
mbedtls_strerror( error, errbuf, 512 );
switch(error) {
case 0:
git_error_set(GIT_ERROR_SSL, "SSL error: unknown error");
break;
case MBEDTLS_ERR_X509_CERT_VERIFY_FAILED:
git_error_set(GIT_ERROR_SSL, "SSL error: %#04x [%x] - %s", error, mbedtls_ssl_get_verify_result(ssl), errbuf);
ret = GIT_ECERTIFICATE;
break;
default:
git_error_set(GIT_ERROR_SSL, "SSL error: %#04x - %s", error, errbuf);
}
return ret;
}
static int ssl_teardown(mbedtls_ssl_context *ssl)
{
int ret = 0;
ret = mbedtls_ssl_close_notify(ssl);
if (ret < 0)
ret = ssl_set_error(ssl, ret);
mbedtls_ssl_free(ssl);
return ret;
}
static int verify_server_cert(mbedtls_ssl_context *ssl)
{
int ret = -1;
if ((ret = mbedtls_ssl_get_verify_result(ssl)) != 0) {
char vrfy_buf[512];
int len = mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), "", ret);
if (len >= 1) vrfy_buf[len - 1] = '\0'; /* Remove trailing \n */
git_error_set(GIT_ERROR_SSL, "the SSL certificate is invalid: %#04x - %s", ret, vrfy_buf);
return GIT_ECERTIFICATE;
}
return 0;
}
typedef struct {
git_stream parent;
git_stream *io;
int owned;
bool connected;
char *host;
mbedtls_ssl_context *ssl;
git_cert_x509 cert_info;
} mbedtls_stream;
static int mbedtls_connect(git_stream *stream)
{
int ret;
mbedtls_stream *st = (mbedtls_stream *) stream;
if (st->owned && (ret = git_stream_connect(st->io)) < 0)
return ret;
st->connected = true;
mbedtls_ssl_set_hostname(st->ssl, st->host);
mbedtls_ssl_set_bio(st->ssl, st->io, bio_write, bio_read, NULL);
if ((ret = mbedtls_ssl_handshake(st->ssl)) != 0)
return ssl_set_error(st->ssl, ret);
return verify_server_cert(st->ssl);
}
static int mbedtls_certificate(git_cert **out, git_stream *stream)
{
unsigned char *encoded_cert;
mbedtls_stream *st = (mbedtls_stream *) stream;
const mbedtls_x509_crt *cert = mbedtls_ssl_get_peer_cert(st->ssl);
if (!cert) {
git_error_set(GIT_ERROR_SSL, "the server did not provide a certificate");
return -1;
}
/* Retrieve the length of the certificate first */
if (cert->raw.len == 0) {
git_error_set(GIT_ERROR_NET, "failed to retrieve certificate information");
return -1;
}
encoded_cert = git__malloc(cert->raw.len);
GIT_ERROR_CHECK_ALLOC(encoded_cert);
memcpy(encoded_cert, cert->raw.p, cert->raw.len);
st->cert_info.parent.cert_type = GIT_CERT_X509;
st->cert_info.data = encoded_cert;
st->cert_info.len = cert->raw.len;
*out = &st->cert_info.parent;
return 0;
}
static int mbedtls_set_proxy(git_stream *stream, const git_proxy_options *proxy_options)
{
mbedtls_stream *st = (mbedtls_stream *) stream;
return git_stream_set_proxy(st->io, proxy_options);
}
static ssize_t mbedtls_stream_write(git_stream *stream, const char *data, size_t len, int flags)
{
mbedtls_stream *st = (mbedtls_stream *) stream;
int written;
GIT_UNUSED(flags);
/*
* `mbedtls_ssl_write` can only represent INT_MAX bytes
* written via its return value. We thus need to clamp
* the maximum number of bytes written.
*/
len = min(len, INT_MAX);
if ((written = mbedtls_ssl_write(st->ssl, (const unsigned char *)data, len)) <= 0)
return ssl_set_error(st->ssl, written);
return written;
}
static ssize_t mbedtls_stream_read(git_stream *stream, void *data, size_t len)
{
mbedtls_stream *st = (mbedtls_stream *) stream;
int ret;
if ((ret = mbedtls_ssl_read(st->ssl, (unsigned char *)data, len)) <= 0)
ssl_set_error(st->ssl, ret);
return ret;
}
static int mbedtls_stream_close(git_stream *stream)
{
mbedtls_stream *st = (mbedtls_stream *) stream;
int ret = 0;
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 mbedtls_stream_free(git_stream *stream)
{
mbedtls_stream *st = (mbedtls_stream *) stream;
if (st->owned)
git_stream_free(st->io);
git__free(st->host);
git__free(st->cert_info.data);
mbedtls_ssl_free(st->ssl);
git__free(st->ssl);
git__free(st);
}
static int mbedtls_stream_wrap(
git_stream **out,
git_stream *in,
const char *host,
int owned)
{
mbedtls_stream *st;
int error;
st = git__calloc(1, sizeof(mbedtls_stream));
GIT_ERROR_CHECK_ALLOC(st);
st->io = in;
st->owned = owned;
st->ssl = git__malloc(sizeof(mbedtls_ssl_context));
GIT_ERROR_CHECK_ALLOC(st->ssl);
mbedtls_ssl_init(st->ssl);
if (mbedtls_ssl_setup(st->ssl, &mbedtls_config)) {
git_error_set(GIT_ERROR_SSL, "failed to create ssl object");
error = -1;
goto out_err;
}
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 = mbedtls_connect;
st->parent.certificate = mbedtls_certificate;
st->parent.set_proxy = mbedtls_set_proxy;
st->parent.read = mbedtls_stream_read;
st->parent.write = mbedtls_stream_write;
st->parent.close = mbedtls_stream_close;
st->parent.free = mbedtls_stream_free;
*out = (git_stream *) st;
return 0;
out_err:
/* ESP FIX: do NOT close/free st->io here — on error the caller keeps
* ownership of `in` (git_mbedtls_stream_new closes+frees it right after;
* the vendored code freed it here too → double free → tlsf abort). */
mbedtls_ssl_free(st->ssl);
git__free(st->ssl);
git__free(st);
return error;
}
int git_mbedtls_stream_wrap(
git_stream **out,
git_stream *in,
const char *host)
{
return mbedtls_stream_wrap(out, in, host, 0);
}
int git_mbedtls_stream_new(
git_stream **out,
const char *host,
const char *port)
{
git_stream *stream;
int error;
GIT_ASSERT_ARG(out);
GIT_ASSERT_ARG(host);
GIT_ASSERT_ARG(port);
if ((error = git_socket_stream_new(&stream, host, port)) < 0)
return error;
if ((error = mbedtls_stream_wrap(out, stream, host, 1)) < 0) {
git_stream_close(stream);
git_stream_free(stream);
}
return error;
}
int git_mbedtls__set_cert_location(const char *file, const char *path)
{
int ret = 0;
char errbuf[512];
GIT_ASSERT_ARG(file || path);
if (has_ca_chain)
mbedtls_x509_crt_free(&mbedtls_ca_chain);
mbedtls_x509_crt_init(&mbedtls_ca_chain);
if (file)
ret = mbedtls_x509_crt_parse_file(&mbedtls_ca_chain, file);
if (ret >= 0 && path)
ret = mbedtls_x509_crt_parse_path(&mbedtls_ca_chain, path);
/* mbedtls_x509_crt_parse_path returns the number of invalid certs on success */
if (ret < 0) {
mbedtls_x509_crt_free(&mbedtls_ca_chain);
mbedtls_strerror( ret, errbuf, 512 );
git_error_set(GIT_ERROR_SSL, "failed to load CA certificates: %#04x - %s", ret, errbuf);
return -1;
}
mbedtls_ssl_conf_ca_chain(&mbedtls_config, &mbedtls_ca_chain, NULL);
has_ca_chain = true;
return 0;
}
#else
#include "stream.h"
int git_mbedtls_stream_global_init(void)
{
return 0;
}
#endif