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linux-steam-integration/src/intercept/main.c
5b59075 Dec 23, 2017
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/*
* This file is part of linux-steam-integration.
*
* Copyright © 2016-2017 Ikey Doherty <ikey@solus-project.com>
*
* linux-steam-integration is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*/
#define _GNU_SOURCE
#include <libgen.h>
#include <link.h>
#include <linux/limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include "../common/common.h"
#include "../common/files.h"
#include "../common/log.h"
#include "config.h"
#include "nica/util.h"
/**
* What's the known process name?
*/
static const char *matched_process = NULL;
static bool lsi_override_replace_with_host(const char *orig_name, const char **soname,
const char *msg);
static bool lsi_override_soname(unsigned int flag, const char *orig_name, const char **soname);
/**
* We support a number of modes, but we mostly exist to make Steam behave
*/
typedef enum {
INTERCEPT_MODE_NONE = 0,
INTERCEPT_MODE_STEAM,
INTERCEPT_MODE_VENDOR_OFFENDER,
} InterceptMode;
/**
* by default, we're not "on"
*/
static InterceptMode work_mode = INTERCEPT_MODE_NONE;
/* Patterns we'll permit Steam to privately load */
static const char *steam_allowed[] = {
/* general */
"libicui18n.so",
"libicuuc.so",
"libavcodec.so.",
"libavformat.so.",
"libavresample.so.",
"libavutil.so.",
"libswscale.so.",
"libx264.so.",
/* core plugins */
"chromehtml.so",
"crashhandler.so",
"filesystem_stdio.so",
"friendsui.so",
"gameoverlayrenderer.so",
"gameoverlayui.so",
"libaudio.so",
"libmiles.so",
"libopenvr_api.so",
"liboverride.so",
"libsteam.so",
"libtier0_s.so",
"libv8.so",
"libvideo.so",
"libvstdlib_s.so",
"serverbrowser.so",
"steamclient.so",
"steamoverlayvulkanlayer.so",
"steamservice.so",
"steamui.so",
"vgui2_s.so",
/* big picture mode */
"panorama",
"libpangoft2-1.0.so",
"libpango-1.0.so",
/* steamwebhelper */
"libcef.so",
/* Swift shader */
"libGLESv2.so",
"libEGL.so",
/* widevine */
"libwidevinecdmadapter.so",
"libwidevinecdm.so",
};
static const char *wanted_steam_processes[] = {
"html5app_steam",
"opengl-program",
"steam",
"steamwebhelper",
};
/**
* Vendor offendors should not be allowed to load replacements for libraries
* that are KNOWN to cause issues, i.e. SDL + libstdc++
*/
static const char *vendor_blacklist[] = {
/* base libraries being replaced will cause a C++ ABI issue when
* loading the mesalib drivers. */
"libgcc_",
"libstdc++",
/* Ensure we don't match weird made up cruft like "libSDL2_locale" */
"libSDL-1.2",
"libSDL2-2",
"libSDL2_ttf",
"libSDL_ttf",
"libSDL2_image",
"libSDL_image",
"libSDL2_mixer",
"libSDL_mixer",
"libSDL2_net",
"libSDL_net",
"libSDL2_gfx",
"libSDL_gfx",
/* vendor-owned */
"libz.so.1",
"libfreetype.so.6",
"libmpg123.so.0",
/* general problem causer. */
"libopenal.so.",
/* glews (provide glew + glew110 in your distro for full compat) */
"libGLEW.so.1.10",
"libGLEW.so.1.12",
/* libglu has stable soname */
"libGLU.so.",
/* Security sensitive libraries should not be replaced */
"libcurl.so.",
#ifdef LSI_OVERRIDE_LIBRESSL
/* Sometimes libressl but this is handled separately. */
"libcrypto.so.",
"libssl.so.",
#else
"libcrypto.so.1.0.0",
"libssl.so.1.0.0",
#endif
/* TODO/FUTURE:
"libaudiofile.so.1", */
};
/**
* Determine if we're in a given process set, i.e. the process name matches
* the given table
*/
static bool is_in_process_set(char *process_name, const char **processes, size_t n_processes)
{
/* Are we some portion of the process set? */
for (size_t i = 0; i < n_processes; i++) {
if (streq(processes[i], process_name)) {
work_mode = INTERCEPT_MODE_STEAM;
matched_process = processes[i];
lsi_log_debug("loading libintercept for '%s'", matched_process);
return true;
}
}
return false;
}
/**
* Find out if we're being executed by a process we actually need to override,
* otherwise we'd not be loaded by rtld-audit
*/
static void check_is_intercept_candidate(void)
{
autofree(char) *nom = NULL;
nom = lsi_get_process_base_name();
if (!nom) {
return;
}
if (is_in_process_set(nom, wanted_steam_processes, ARRAY_SIZE(wanted_steam_processes))) {
work_mode = INTERCEPT_MODE_STEAM;
} else {
work_mode = INTERCEPT_MODE_VENDOR_OFFENDER;
matched_process = "vendor_offender";
}
lsi_log_set_id(matched_process);
}
/**
* la_version is our main entry point and will only continue if our
* process is explicitly Steam
*/
_nica_public_ unsigned int la_version(unsigned int supported_version)
{
/* Unfortunately glibc will die if we tell it to skip us .. */
check_is_intercept_candidate();
return supported_version;
}
/**
* lsi_search_steam handles whitelisting for the main Steam processes
*/
char *lsi_search_steam(unsigned int flag, const char *name)
{
const char *soname = NULL;
/* Preemptively catch transmutations */
if (lsi_override_soname(flag, name, &soname)) {
return (char *)soname;
}
if (!lsi_file_exists(name)) {
return (char *)name;
}
/* Find out if its a Steam private lib.. These are relative "./" files too! */
if (name && (strstr(name, "/Steam/") || strncmp(name, "./", 2) == 0)) {
for (size_t i = 0; i < ARRAY_SIZE(steam_allowed); i++) {
if (strstr(name, steam_allowed[i])) {
return (char *)name;
}
}
lsi_log_debug("blacklisted loading of vendor library: \033[34;1m%s\033[0m", name);
return NULL;
}
return (char *)name;
}
/**
* Source identifier patterns that indicate a soname replacement is happening.
* Note that this is a basic pattern match for the soname and just allows us
* to lookup the transmute target
*/
static const char *vendor_transmute_source[] = {
/* Common */
"libSDL2-2.0.",
"libSDL2_image-2.0.",
/* ".so" renames */
"libSDL2_ttf.so",
"libSDL2_image.so",
"libSDL2_mixer.so",
"libSDL2_net.so",
"libSDL2_gfx.so",
/* libressl (security updates) */
#ifdef LSI_OVERRIDE_LIBRESSL
"libcrypto.so.36",
"libssl.so.37",
#endif
/* old name for openal */
"libopenal-soft.so.1",
/* invalid curls */
"libcurl-gnutls.so.3",
"libcurl.so.3",
"libbz2.so.1.0",
"libudev.so.0",
};
/**
* The transmute target is the intended replacement for any source name, assuming
* that the soname doesn't identically match the currently requested soname.
* This allows us to do on the fly replacements for re-soname'd libraries.
*/
static const char *vendor_transmute_target[] = {
/* Common */
"libSDL2-2.0.so.0",
"libSDL2_image-2.0.so.0",
/* ".so" renames */
"libSDL2_ttf-2.0.so.0",
"libSDL2_image-2.0.so.0",
"libSDL2_mixer-2.0.so.0",
"libSDL2_net-2.0.so.0",
"libSDL2_gfx-1.0.so.0",
/* libressl (security updates) */
#if defined(LSI_LIBRESSL_MODE_SHIM)
"libcrypto" LSI_LIBRESSL_SUFFIX ".so",
"libssl" LSI_LIBRESSL_SUFFIX ".so",
#elif defined(LSI_LIBRESSL_MODE_NATIVE)
"libcrypto.so.1.0.0",
"libssl.so.1.0.0",
#endif
/* new name for openal */
"libopenal.so.1",
/* invalid curls */
"libcurl-gnutls.so.4",
"libcurl.so.4",
"libbz2.so.1.0.6",
"libudev.so.1",
};
/**
* Every so often a game comes along that does the following:
*
* open("path") ? dlopen("path").
* Except: path = "*.dll", dlopen() is transformed to ".dll.so"
*
* This is unrelated to the ".la" errors
*/
static bool lsi_override_dll_fail(const char *orig_name, const char **soname)
{
size_t len = strlen(orig_name);
static char path_lookup[PATH_MAX];
if (len < 7) {
return false;
}
if (strncmp(orig_name + (len - 7), ".dll.so", 7) != 0) {
return false;
}
if (!strncpy(path_lookup, orig_name, len - 3)) {
return false;
}
if (!lsi_file_exists(path_lookup)) {
return false;
}
*soname = path_lookup;
lsi_log_debug("fixed invalid suffix dlopen() \033[31;1m%s\033[0m -> \033[34;1m%s\033[0m",
orig_name,
path_lookup);
return true;
}
/**
* Mono games might try looking for /x86/ plugin directory for a 64-bit process,
* as seen with testing with Project Highrise.
*
* This function simply redirects the dlopen to the file in the x86_64 directory,
* if it actually exists.
*
* Typically this is for libCSteamWorks, libsteam_api, and Unity ScreenSelector.so
*/
#if UINTPTR_MAX == 0xffffffffffffffff
static bool lsi_override_x86_derp(const char *orig_name, const char **soname)
{
static char path_copy[PATH_MAX];
static char path_lookup[PATH_MAX];
char *small_name = NULL;
char *dir = NULL;
if (!(strstr(orig_name, "/Plugins/x86/") && strstr(orig_name, ".so"))) {
return false;
}
if (!strcpy(path_copy, orig_name)) {
return false;
}
small_name = basename(path_copy);
dir = dirname(path_copy);
if (snprintf(path_lookup, sizeof(path_lookup), "%s/../x86_64/%s", dir, small_name) < 0) {
return false;
}
if (!lsi_file_exists(path_lookup)) {
return false;
}
*soname = path_lookup;
lsi_log_debug(
"fixed invalid architecture dlopen() \033[31;1m%s\033[0m -> \033[34;1m%s\033[0m",
orig_name,
path_lookup);
return true;
#else
static bool lsi_override_x86_derp(__lsi_unused__ const char *orig_name,
__lsi_unused__ const char **soname)
{
/* Don't perform x86 translation on 32-bit machines */
return false;
#endif
}
/**
* Internal helper for path replacement to host lib
*/
static bool lsi_override_replace_with_host(const char *orig_name, const char **soname,
const char *msg)
{
static char path_lookup[PATH_MAX];
static char path_copy[PATH_MAX];
char *small_name = NULL;
static const char *library_paths[] = {
#if UINTPTR_MAX == 0xffffffffffffffff
#ifdef HAVE_SNAPD_SUPPORT
"/var/lib/snapd/lib/gl",
#endif
"/usr/lib64",
"/usr/lib/x86_64-linux-gnu",
"/usr/lib",
#else
#ifdef HAVE_SNAPD_SUPPORT
"/var/lib/snapd/lib/gl32",
#endif
"/usr/lib32",
"/usr/lib/i386-linux-gnu",
"/usr/lib",
#endif
};
if (!strcpy(path_copy, orig_name)) {
return false;
}
small_name = basename(path_copy);
/* Iterate all of the library paths for this process architecture and try
* to find a system variant of the library instead of allowing the process
* to dlopen() the vendored version.
*/
for (size_t i = 0; i < ARRAY_SIZE(library_paths); i++) {
if (snprintf(path_lookup,
sizeof(path_lookup),
"%s/%s",
library_paths[i],
small_name) < 0) {
return false;
}
if (!lsi_file_exists(path_lookup)) {
continue;
}
/* We hit a match but it was identical to our expectation */
if (strcmp(path_lookup, orig_name) == 0) {
return false;
}
*soname = path_lookup;
if (!msg) {
return true;
}
lsi_log_debug("%s \033[31;1m%s\033[0m -> \033[34;1m%s\033[0m",
msg,
orig_name,
path_lookup);
return true;
}
return false;
}
/**
* lsi_override_dlopen is used to override simple dlopen() requests typically
* used by Mono games, i.e.:
*
* <dllmap dll="SDL2.dll" os="linux" cpu="x86-64" target="./lib64/libSDL2-2.0.so.0"/>
*
* We'll attempt to do a trivial lookup for "/usr/./lib64/libSDL2-2.0.so.0 in this
* case.
*/
static bool lsi_override_dlopen(const char *orig_name, const char **soname)
{
if (lsi_override_dll_fail(orig_name, soname)) {
return true;
}
if (!lsi_file_exists(orig_name)) {
return false;
}
if (lsi_override_x86_derp(orig_name, soname)) {
return true;
}
return lsi_override_replace_with_host(orig_name, soname, "intercepting vendor dlopen()");
}
/**
* lsi_override_soname will deal with LA_SER_ORIG entries, i.e. the original
* soname request when the linker tries to load a library.
*
* Certain Steam games (notably Feral Interactive ports) use their own vendored
* SDL libraries with changed sonames, which are implicitly blacklisted by the
* lsi_blacklist_vendor function.
*
* As such, we intercept those renamed libraries, and convert their names back
* to the ABI stable system libraries on the fly.
*/
static bool lsi_override_soname(unsigned int flag, const char *orig_name, const char **soname)
{
*soname = NULL;
/* We only need to deal with LA_SER_ORIG */
if ((flag & LA_SER_ORIG) != LA_SER_ORIG) {
return false;
}
/* Don't transform dlopen */
if (strstr(orig_name, "/")) {
return lsi_override_dlopen(orig_name, soname);
}
for (size_t i = 0; i < ARRAY_SIZE(vendor_transmute_source); i++) {
if (!strstr(orig_name, vendor_transmute_source[i])) {
continue;
}
/* Ensure we're not just replacing the same thing here as the
* string would be identical, no real replacement would happen,
* and ld will be confused about memory and die.
*/
if (streq(orig_name, vendor_transmute_target[i])) {
continue;
}
*soname = vendor_transmute_target[i];
lsi_log_debug(
"transforming vendor soname: \033[31;1m%s\033[0m -> \033[34;1m%s\033[0m",
orig_name,
*soname);
return true;
}
return false;
}
/**
* If the library exists locally, and we're attempting to load this from a
* relative location, strongly attempt to actually use the system-version instead.
*
* Thus, if our CWD is our LD_LIBRARY_PATH and contains "libfreetype.so.6", we'll
* try to use the host version of the library if that exists, instead of relying
* on the locally vendored, potentially insecure/buggy version.
*/
static bool lsi_override_local(unsigned int flag, const char *orig_name, const char **soname)
{
*soname = NULL;
/* We only need to deal with LA_SER_ORIG */
if ((flag & LA_SER_ORIG) != LA_SER_ORIG) {
return false;
}
/* We only care about relative paths */
if (strstr(orig_name, "/")) {
return false;
}
/* We also only care about relative paths */
if (!lsi_file_exists(orig_name)) {
return false;
}
/* Resolve all paths back to the real library path version if they exist */
for (size_t i = 0; i < ARRAY_SIZE(vendor_blacklist); i++) {
if (!strstr(orig_name, vendor_blacklist[i])) {
continue;
}
return lsi_override_replace_with_host(orig_name,
soname,
"forcing use of host library");
}
return false;
}
char *lsi_blacklist_vendor(unsigned int flag, const char *name)
{
/* Find out if it exists */
bool file_exists = lsi_file_exists(name);
const char *override_soname = NULL;
/* Find out if we have to rename some libraries on the fly */
if (lsi_override_soname(flag, name, &override_soname)) {
return (char *)override_soname;
}
/* Locally exists due to directory foobar */
if (lsi_override_local(flag, name, &override_soname)) {
return (char *)override_soname;
}
/* Find out if its a Steam private lib.. These are relative "./" files too! */
if (name && (strstr(name, "/Steam/") || strstr(name, "/steamapps/") ||
strncmp(name, "./", 2) == 0)) {
for (size_t i = 0; i < ARRAY_SIZE(vendor_blacklist); i++) {
if (!strstr(name, vendor_blacklist[i])) {
continue;
}
if (file_exists) {
lsi_log_debug(
"blacklisted loading of vendor library: \033[34;1m%s\033[0m",
name);
}
return NULL;
}
/* Allowed to exist */
return (char *)name;
}
return (char *)name;
}
/**
* la_objsearch will allow us to blacklist certain LD_LIBRARY_PATH duplicate
* libraries being loaded by the Steam client, such as the broken libSDL shipped
* as a private vendored lib
*/
_nica_public_ char *la_objsearch(const char *name, __lsi_unused__ uintptr_t *cookie,
unsigned int flag)
{
switch (work_mode) {
case INTERCEPT_MODE_STEAM:
return lsi_search_steam(flag, name);
case INTERCEPT_MODE_VENDOR_OFFENDER:
return lsi_blacklist_vendor(flag, name);
case INTERCEPT_MODE_NONE:
default:
return (char *)name;
}
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=8 tabstop=8 expandtab:
* :indentSize=8:tabSize=8:noTabs=true:
*/