napi: fix memory corruption vulnerability

Fixes: https://hackerone.com/reports/784186
CVE-ID: CVE-2020-8174
PR-URL: https://github.com/nodejs-private/node-private/pull/195
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
This commit is contained in:
Tobias Nießen 2020-01-27 13:38:36 -04:00 committed by Michaël Zasso
parent 0cb194ec6a
commit 656260b4b6
No known key found for this signature in database
GPG Key ID: 770F7A9A5AE15600
3 changed files with 31 additions and 3 deletions

View File

@ -2177,7 +2177,7 @@ napi_status napi_get_value_string_latin1(napi_env env,
if (!buf) {
CHECK_ARG(env, result);
*result = val.As<v8::String>()->Length();
} else {
} else if (bufsize != 0) {
int copied =
val.As<v8::String>()->WriteOneByte(env->isolate,
reinterpret_cast<uint8_t*>(buf),
@ -2189,6 +2189,8 @@ napi_status napi_get_value_string_latin1(napi_env env,
if (result != nullptr) {
*result = copied;
}
} else if (result != nullptr) {
*result = 0;
}
return napi_clear_last_error(env);
@ -2216,7 +2218,7 @@ napi_status napi_get_value_string_utf8(napi_env env,
if (!buf) {
CHECK_ARG(env, result);
*result = val.As<v8::String>()->Utf8Length(env->isolate);
} else {
} else if (bufsize != 0) {
int copied = val.As<v8::String>()->WriteUtf8(
env->isolate,
buf,
@ -2228,6 +2230,8 @@ napi_status napi_get_value_string_utf8(napi_env env,
if (result != nullptr) {
*result = copied;
}
} else if (result != nullptr) {
*result = 0;
}
return napi_clear_last_error(env);
@ -2256,7 +2260,7 @@ napi_status napi_get_value_string_utf16(napi_env env,
CHECK_ARG(env, result);
// V8 assumes UTF-16 length is the same as the number of characters.
*result = val.As<v8::String>()->Length();
} else {
} else if (bufsize != 0) {
int copied = val.As<v8::String>()->Write(env->isolate,
reinterpret_cast<uint16_t*>(buf),
0,
@ -2267,6 +2271,8 @@ napi_status napi_get_value_string_utf16(napi_env env,
if (result != nullptr) {
*result = copied;
}
} else if (result != nullptr) {
*result = 0;
}
return napi_clear_last_error(env);

View File

@ -81,3 +81,5 @@ assert.throws(() => {
assert.throws(() => {
test_string.TestLargeUtf16();
}, /^Error: Invalid argument$/);
test_string.TestMemoryCorruption(' '.repeat(64 * 1024));

View File

@ -1,4 +1,5 @@
#include <limits.h> // INT_MAX
#include <string.h>
#include <js_native_api.h>
#include "../common.h"
@ -244,6 +245,24 @@ static napi_value TestLargeUtf16(napi_env env, napi_callback_info info) {
return output;
}
static napi_value TestMemoryCorruption(napi_env env, napi_callback_info info) {
size_t argc = 1;
napi_value args[1];
NAPI_CALL(env, napi_get_cb_info(env, info, &argc, args, NULL, NULL));
NAPI_ASSERT(env, argc == 1, "Wrong number of arguments");
char buf[10] = { 0 };
NAPI_CALL(env, napi_get_value_string_utf8(env, args[0], buf, 0, NULL));
char zero[10] = { 0 };
if (memcmp(buf, zero, sizeof(buf)) != 0) {
NAPI_CALL(env, napi_throw_error(env, NULL, "Buffer overwritten"));
}
return NULL;
}
EXTERN_C_START
napi_value Init(napi_env env, napi_value exports) {
napi_property_descriptor properties[] = {
@ -258,6 +277,7 @@ napi_value Init(napi_env env, napi_value exports) {
DECLARE_NAPI_PROPERTY("TestLargeUtf8", TestLargeUtf8),
DECLARE_NAPI_PROPERTY("TestLargeLatin1", TestLargeLatin1),
DECLARE_NAPI_PROPERTY("TestLargeUtf16", TestLargeUtf16),
DECLARE_NAPI_PROPERTY("TestMemoryCorruption", TestMemoryCorruption),
};
NAPI_CALL(env, napi_define_properties(