Mercurial > vim
view src/iscygpty.c @ 33664:06b59278bfcf v9.0.2070
patch 9.0.2070: [security] disallow setting env in restricted mode
Commit: https://github.com/vim/vim/commit/6b89dd6a7257a1e2e9c7ea070b407bc4674a5118
Author: Christian Brabandt <cb@256bit.org>
Date: Thu Oct 26 22:14:17 2023 +0200
patch 9.0.2070: [security] disallow setting env in restricted mode
Problem: [security] disallow setting env in restricted mode
Solution: Setting environment variables in restricted mode could
potentially be used to execute shell commands. Disallow this.
restricted mode: disable allow setting of environment variables
Setting environment variables in restricted mode, may have some unwanted
consequences. So, for example by setting $GCONV_PATH in restricted mode
and then calling the iconv() function, one may be able to execute some
unwanted payload, because the `iconv_open()` function internally uses
the `$GCONV_PATH` variable to find its conversion data.
So let's disable setting environment variables, even so this is no
complete protection, since we are not clearing the existing environment.
I tried a few ways but wasn't successful :(
One could also argue to disable the iconv() function completely in
restricted mode, but who knows what other API functions can be
influenced by setting some other unrelated environment variables.
So let's leave it as it is currently.
closes: #13394
See: https://huntr.com/bounties/b0a2eda1-459c-4e36-98e6-0cc7d7faccfe/
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Thu, 26 Oct 2023 22:30:03 +0200 |
parents | 1ffdcd8a424e |
children |
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/* * iscygpty.c -- part of ptycheck * https://github.com/k-takata/ptycheck * * Copyright (c) 2015-2023 K.Takata * * You can redistribute it and/or modify it under the terms of either * the MIT license (as described below) or the Vim license. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #ifdef _WIN32 #include <ctype.h> #include <io.h> #include <wchar.h> #include <windows.h> #ifdef USE_FILEEXTD // VC 7.1 or earlier doesn't support SAL. # if !defined(_MSC_VER) || (_MSC_VER < 1400) # define __out # define __in # define __in_opt # endif // Win32 FileID API Library: // http://www.microsoft.com/en-us/download/details.aspx?id=22599 // Needed for WinXP. # include <fileextd.h> #else // USE_FILEEXTD // VC 8 or earlier. # if defined(_MSC_VER) && (_MSC_VER < 1500) # ifdef ENABLE_STUB_IMPL # define STUB_IMPL # else # error "Win32 FileID API Library is required for VC2005 or earlier." # endif # endif #endif // USE_FILEEXTD #ifdef __MINGW32__ # define UNUSED __attribute__((unused)) #else # define UNUSED #endif #include "iscygpty.h" //#define USE_DYNFILEID #ifdef USE_DYNFILEID typedef BOOL (WINAPI *pfnGetFileInformationByHandleEx)( HANDLE hFile, FILE_INFO_BY_HANDLE_CLASS FileInformationClass, LPVOID lpFileInformation, DWORD dwBufferSize); static pfnGetFileInformationByHandleEx pGetFileInformationByHandleEx = NULL; # ifndef USE_FILEEXTD static BOOL WINAPI stub_GetFileInformationByHandleEx( HANDLE hFile UNUSED, FILE_INFO_BY_HANDLE_CLASS FileInformationClass UNUSED, LPVOID lpFileInformation UNUSED, DWORD dwBufferSize UNUSED) { return FALSE; } # endif static void setup_fileid_api(void) { if (pGetFileInformationByHandleEx != NULL) { return; } pGetFileInformationByHandleEx = (pfnGetFileInformationByHandleEx) GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "GetFileInformationByHandleEx"); if (pGetFileInformationByHandleEx == NULL) { # ifdef USE_FILEEXTD pGetFileInformationByHandleEx = GetFileInformationByHandleEx; # else pGetFileInformationByHandleEx = stub_GetFileInformationByHandleEx; # endif } } #else # define pGetFileInformationByHandleEx GetFileInformationByHandleEx # define setup_fileid_api() #endif #define is_wprefix(s, prefix) \ (wcsncmp((s), (prefix), sizeof(prefix) / sizeof(WCHAR) - 1) == 0) // Check if the fd is a cygwin/msys's pty. int is_cygpty(int fd) { #ifdef STUB_IMPL return 0; #else HANDLE h; const int size = sizeof(FILE_NAME_INFO) + sizeof(WCHAR) * (MAX_PATH - 1); FILE_NAME_INFO *nameinfo; WCHAR *p = NULL; setup_fileid_api(); h = (HANDLE) _get_osfhandle(fd); if (h == INVALID_HANDLE_VALUE) { return 0; } // Cygwin/msys's pty is a pipe. if (GetFileType(h) != FILE_TYPE_PIPE) { return 0; } nameinfo = malloc(size + sizeof(WCHAR)); if (nameinfo == NULL) { return 0; } // Check the name of the pipe: // "\\{cygwin,msys}-XXXXXXXXXXXXXXXX-ptyN-{from,to}-master" if (pGetFileInformationByHandleEx(h, FileNameInfo, nameinfo, size)) { nameinfo->FileName[nameinfo->FileNameLength / sizeof(WCHAR)] = L'\0'; p = nameinfo->FileName; if (is_wprefix(p, L"\\cygwin-")) { // Cygwin p += 8; } else if (is_wprefix(p, L"\\msys-")) { // MSYS and MSYS2 p += 6; } else { p = NULL; } if (p != NULL) { // Skip 16-digit hexadecimal. while (*p && iswascii(*p) && isxdigit(*p)) ++p; if (is_wprefix(p, L"-pty")) { p += 4; } else { p = NULL; } } if (p != NULL) { // Skip pty number. while (*p && iswascii(*p) && isdigit(*p)) ++p; if (is_wprefix(p, L"-from-master")) { //p += 12; } else if (is_wprefix(p, L"-to-master")) { //p += 10; } else { p = NULL; } } } free(nameinfo); return (p != NULL); #endif // STUB_IMPL } // Check if at least one cygwin/msys pty is used. int is_cygpty_used(void) { int fd, ret = 0; for (fd = 0; fd < 3; fd++) { ret |= is_cygpty(fd); } return ret; } #endif // _WIN32 // vim: set ts=4 sw=4: