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474 lines (379 loc) · 12.8 KB
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#include "env-inl.h"
#include "node_external_reference.h"
#include "node_internals.h"
#include "util-inl.h"
#ifdef NODE_IMPLEMENTS_POSIX_CREDENTIALS
#include <grp.h> // getgrnam()
#include <pwd.h> // getpwnam()
#endif // NODE_IMPLEMENTS_POSIX_CREDENTIALS
#if !defined(_MSC_VER)
#include <unistd.h> // setuid, getuid
#endif
#ifdef __linux__
#include <linux/capability.h>
#include <sys/syscall.h>
#endif // __linux__
namespace node {
using v8::Array;
using v8::Context;
using v8::FunctionCallbackInfo;
using v8::HandleScope;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::Object;
using v8::String;
using v8::TryCatch;
using v8::Uint32;
using v8::Value;
namespace per_process {
bool linux_at_secure = false;
} // namespace per_process
namespace credentials {
#if defined(__linux__)
// Returns true if the current process only has the passed-in capability.
bool HasOnly(int capability) {
DCHECK(cap_valid(capability));
struct __user_cap_data_struct cap_data[2];
struct __user_cap_header_struct cap_header_data = {
_LINUX_CAPABILITY_VERSION_3,
getpid()};
if (syscall(SYS_capget, &cap_header_data, &cap_data) != 0) {
return false;
}
if (capability < 32) {
return cap_data[0].permitted ==
static_cast<unsigned int>(CAP_TO_MASK(capability));
}
return cap_data[1].permitted ==
static_cast<unsigned int>(CAP_TO_MASK(capability));
}
#endif
// Look up the environment variable and allow the lookup if the current
// process only has the capability CAP_NET_BIND_SERVICE set. If the current
// process does not have any capabilities set and the process is running as
// setuid root then lookup will not be allowed.
bool SafeGetenv(const char* key, std::string* text, Environment* env) {
#if !defined(__CloudABI__) && !defined(_WIN32)
#if defined(__linux__)
if ((!HasOnly(CAP_NET_BIND_SERVICE) && per_process::linux_at_secure) ||
getuid() != geteuid() || getgid() != getegid())
#else
if (per_process::linux_at_secure || getuid() != geteuid() ||
getgid() != getegid())
#endif
goto fail;
#endif
if (env != nullptr) {
HandleScope handle_scope(env->isolate());
TryCatch ignore_errors(env->isolate());
MaybeLocal<String> maybe_value = env->env_vars()->Get(
env->isolate(),
String::NewFromUtf8(env->isolate(), key).ToLocalChecked());
Local<String> value;
if (!maybe_value.ToLocal(&value)) goto fail;
String::Utf8Value utf8_value(env->isolate(), value);
if (*utf8_value == nullptr) goto fail;
*text = std::string(*utf8_value, utf8_value.length());
return true;
}
{
Mutex::ScopedLock lock(per_process::env_var_mutex);
size_t init_sz = 256;
MaybeStackBuffer<char, 256> val;
int ret = uv_os_getenv(key, *val, &init_sz);
if (ret == UV_ENOBUFS) {
// Buffer is not large enough, reallocate to the updated init_sz
// and fetch env value again.
val.AllocateSufficientStorage(init_sz);
ret = uv_os_getenv(key, *val, &init_sz);
}
if (ret >= 0) { // Env key value fetch success.
*text = *val;
return true;
}
}
fail:
text->clear();
return false;
}
static void SafeGetenv(const FunctionCallbackInfo<Value>& args) {
CHECK(args[0]->IsString());
Environment* env = Environment::GetCurrent(args);
Isolate* isolate = env->isolate();
Utf8Value strenvtag(isolate, args[0]);
std::string text;
if (!SafeGetenv(*strenvtag, &text, env)) return;
Local<Value> result =
ToV8Value(isolate->GetCurrentContext(), text).ToLocalChecked();
args.GetReturnValue().Set(result);
}
#ifdef NODE_IMPLEMENTS_POSIX_CREDENTIALS
static const uid_t uid_not_found = static_cast<uid_t>(-1);
static const gid_t gid_not_found = static_cast<gid_t>(-1);
static uid_t uid_by_name(const char* name) {
struct passwd pwd;
struct passwd* pp;
char buf[8192];
errno = 0;
pp = nullptr;
if (getpwnam_r(name, &pwd, buf, sizeof(buf), &pp) == 0 && pp != nullptr)
return pp->pw_uid;
return uid_not_found;
}
static char* name_by_uid(uid_t uid) {
struct passwd pwd;
struct passwd* pp;
char buf[8192];
int rc;
errno = 0;
pp = nullptr;
if ((rc = getpwuid_r(uid, &pwd, buf, sizeof(buf), &pp)) == 0 &&
pp != nullptr) {
return strdup(pp->pw_name);
}
if (rc == 0) errno = ENOENT;
return nullptr;
}
static gid_t gid_by_name(const char* name) {
struct group pwd;
struct group* pp;
char buf[8192];
errno = 0;
pp = nullptr;
if (getgrnam_r(name, &pwd, buf, sizeof(buf), &pp) == 0 && pp != nullptr)
return pp->gr_gid;
return gid_not_found;
}
#if 0 // For future use.
static const char* name_by_gid(gid_t gid) {
struct group pwd;
struct group* pp;
char buf[8192];
int rc;
errno = 0;
pp = nullptr;
if ((rc = getgrgid_r(gid, &pwd, buf, sizeof(buf), &pp)) == 0 &&
pp != nullptr) {
return strdup(pp->gr_name);
}
if (rc == 0)
errno = ENOENT;
return nullptr;
}
#endif
static uid_t uid_by_name(Isolate* isolate, Local<Value> value) {
if (value->IsUint32()) {
return static_cast<uid_t>(value.As<Uint32>()->Value());
} else {
Utf8Value name(isolate, value);
return uid_by_name(*name);
}
}
static gid_t gid_by_name(Isolate* isolate, Local<Value> value) {
if (value->IsUint32()) {
return static_cast<gid_t>(value.As<Uint32>()->Value());
} else {
Utf8Value name(isolate, value);
return gid_by_name(*name);
}
}
static void GetUid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->has_run_bootstrapping_code());
// uid_t is an uint32_t on all supported platforms.
args.GetReturnValue().Set(static_cast<uint32_t>(getuid()));
}
static void GetGid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->has_run_bootstrapping_code());
// gid_t is an uint32_t on all supported platforms.
args.GetReturnValue().Set(static_cast<uint32_t>(getgid()));
}
static void GetEUid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->has_run_bootstrapping_code());
// uid_t is an uint32_t on all supported platforms.
args.GetReturnValue().Set(static_cast<uint32_t>(geteuid()));
}
static void GetEGid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->has_run_bootstrapping_code());
// gid_t is an uint32_t on all supported platforms.
args.GetReturnValue().Set(static_cast<uint32_t>(getegid()));
}
static void SetGid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->owns_process_state());
CHECK_EQ(args.Length(), 1);
CHECK(args[0]->IsUint32() || args[0]->IsString());
gid_t gid = gid_by_name(env->isolate(), args[0]);
if (gid == gid_not_found) {
// Tells JS to throw ERR_INVALID_CREDENTIAL
args.GetReturnValue().Set(1);
} else if (setgid(gid)) {
env->ThrowErrnoException(errno, "setgid");
} else {
args.GetReturnValue().Set(0);
}
}
static void SetEGid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->owns_process_state());
CHECK_EQ(args.Length(), 1);
CHECK(args[0]->IsUint32() || args[0]->IsString());
gid_t gid = gid_by_name(env->isolate(), args[0]);
if (gid == gid_not_found) {
// Tells JS to throw ERR_INVALID_CREDENTIAL
args.GetReturnValue().Set(1);
} else if (setegid(gid)) {
env->ThrowErrnoException(errno, "setegid");
} else {
args.GetReturnValue().Set(0);
}
}
static void SetUid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->owns_process_state());
CHECK_EQ(args.Length(), 1);
CHECK(args[0]->IsUint32() || args[0]->IsString());
uid_t uid = uid_by_name(env->isolate(), args[0]);
if (uid == uid_not_found) {
// Tells JS to throw ERR_INVALID_CREDENTIAL
args.GetReturnValue().Set(1);
} else if (setuid(uid)) {
env->ThrowErrnoException(errno, "setuid");
} else {
args.GetReturnValue().Set(0);
}
}
static void SetEUid(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->owns_process_state());
CHECK_EQ(args.Length(), 1);
CHECK(args[0]->IsUint32() || args[0]->IsString());
uid_t uid = uid_by_name(env->isolate(), args[0]);
if (uid == uid_not_found) {
// Tells JS to throw ERR_INVALID_CREDENTIAL
args.GetReturnValue().Set(1);
} else if (seteuid(uid)) {
env->ThrowErrnoException(errno, "seteuid");
} else {
args.GetReturnValue().Set(0);
}
}
static void GetGroups(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(env->has_run_bootstrapping_code());
int ngroups = getgroups(0, nullptr);
if (ngroups == -1) return env->ThrowErrnoException(errno, "getgroups");
std::vector<gid_t> groups(ngroups);
ngroups = getgroups(ngroups, groups.data());
if (ngroups == -1)
return env->ThrowErrnoException(errno, "getgroups");
groups.resize(ngroups);
gid_t egid = getegid();
if (std::find(groups.begin(), groups.end(), egid) == groups.end())
groups.push_back(egid);
MaybeLocal<Value> array = ToV8Value(env->context(), groups);
if (!array.IsEmpty())
args.GetReturnValue().Set(array.ToLocalChecked());
}
static void SetGroups(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK_EQ(args.Length(), 1);
CHECK(args[0]->IsArray());
Local<Array> groups_list = args[0].As<Array>();
size_t size = groups_list->Length();
MaybeStackBuffer<gid_t, 64> groups(size);
for (size_t i = 0; i < size; i++) {
gid_t gid = gid_by_name(
env->isolate(), groups_list->Get(env->context(), i).ToLocalChecked());
if (gid == gid_not_found) {
// Tells JS to throw ERR_INVALID_CREDENTIAL
args.GetReturnValue().Set(static_cast<uint32_t>(i + 1));
return;
}
groups[i] = gid;
}
int rc = setgroups(size, *groups);
if (rc == -1) return env->ThrowErrnoException(errno, "setgroups");
args.GetReturnValue().Set(0);
}
static void InitGroups(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK_EQ(args.Length(), 2);
CHECK(args[0]->IsUint32() || args[0]->IsString());
CHECK(args[1]->IsUint32() || args[1]->IsString());
Utf8Value arg0(env->isolate(), args[0]);
gid_t extra_group;
bool must_free;
char* user;
if (args[0]->IsUint32()) {
user = name_by_uid(args[0].As<Uint32>()->Value());
must_free = true;
} else {
user = *arg0;
must_free = false;
}
if (user == nullptr) {
// Tells JS to throw ERR_INVALID_CREDENTIAL
return args.GetReturnValue().Set(1);
}
extra_group = gid_by_name(env->isolate(), args[1]);
if (extra_group == gid_not_found) {
if (must_free) free(user);
// Tells JS to throw ERR_INVALID_CREDENTIAL
return args.GetReturnValue().Set(2);
}
int rc = initgroups(user, extra_group);
if (must_free) free(user);
if (rc) return env->ThrowErrnoException(errno, "initgroups");
args.GetReturnValue().Set(0);
}
#endif // NODE_IMPLEMENTS_POSIX_CREDENTIALS
void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
registry->Register(SafeGetenv);
#ifdef NODE_IMPLEMENTS_POSIX_CREDENTIALS
registry->Register(GetUid);
registry->Register(GetEUid);
registry->Register(GetGid);
registry->Register(GetEGid);
registry->Register(GetGroups);
registry->Register(InitGroups);
registry->Register(SetEGid);
registry->Register(SetEUid);
registry->Register(SetGid);
registry->Register(SetUid);
registry->Register(SetGroups);
#endif // NODE_IMPLEMENTS_POSIX_CREDENTIALS
}
static void Initialize(Local<Object> target,
Local<Value> unused,
Local<Context> context,
void* priv) {
Environment* env = Environment::GetCurrent(context);
Isolate* isolate = env->isolate();
env->SetMethod(target, "safeGetenv", SafeGetenv);
#ifdef NODE_IMPLEMENTS_POSIX_CREDENTIALS
READONLY_TRUE_PROPERTY(target, "implementsPosixCredentials");
env->SetMethodNoSideEffect(target, "getuid", GetUid);
env->SetMethodNoSideEffect(target, "geteuid", GetEUid);
env->SetMethodNoSideEffect(target, "getgid", GetGid);
env->SetMethodNoSideEffect(target, "getegid", GetEGid);
env->SetMethodNoSideEffect(target, "getgroups", GetGroups);
if (env->owns_process_state()) {
env->SetMethod(target, "initgroups", InitGroups);
env->SetMethod(target, "setegid", SetEGid);
env->SetMethod(target, "seteuid", SetEUid);
env->SetMethod(target, "setgid", SetGid);
env->SetMethod(target, "setuid", SetUid);
env->SetMethod(target, "setgroups", SetGroups);
}
#endif // NODE_IMPLEMENTS_POSIX_CREDENTIALS
}
} // namespace credentials
} // namespace node
NODE_MODULE_CONTEXT_AWARE_INTERNAL(credentials, node::credentials::Initialize)
NODE_MODULE_EXTERNAL_REFERENCE(credentials,
node::credentials::RegisterExternalReferences)