Linux/FreeBSD: Use of 'sudo -n uptime' command to check whether user has an active 'sudo' session instead of the use of a 'dummy' password. (#513)

Signed-off-by: El Mostafa IDRASSI <el-mostafa.idrassi@prestalab.net>
This commit is contained in:
El Mostafa Idrassi 2019-10-08 17:11:50 +01:00 committed by Mounir IDRASSI
parent 15a8cde6f5
commit 9463a628a6

View File

@ -288,6 +288,41 @@ namespace VeraCrypt
request.FastElevation = !ElevatedServiceAvailable;
request.ApplicationExecutablePath = Core->GetApplicationExecutablePath();
// Test if the user has an active "sudo" session.
// This is only done under Linux / FreeBSD by executing the command 'sudo -n uptime'.
// In case a "sudo" session is active, the result of the command contains the string 'load average'.
// Otherwise, the result contains "sudo: a password is required".
// This may not work on all OSX versions because of a bug in sudo in its version 1.7.10,
// therefore we keep the old behaviour of sending a 'dummy' password under OSX.
// See : https://superuser.com/questions/902826/why-does-sudo-n-on-mac-os-x-always-return-0
#if defined(TC_LINUX ) || defined (TC_FREEBSD)
// Set to false to force the 'WarningEvent' to be raised in case of and elevation exception.
request.FastElevation = false;
std::vector<char> buffer(128, 0);
std::string result;
FILE* pipe = popen("sudo -n uptime 2>&1 | grep 'load average' | wc -l", "r"); // We redirect stderr to stdout (2>&1) to be able to catch the result of the command
if (pipe)
{
while (!feof(pipe))
{
if (fgets(buffer.data(), 128, pipe) != nullptr)
result += buffer.data();
}
fflush(pipe);
pclose(pipe);
pipe = NULL;
if (!result.empty() && strlen(result.c_str()) != 0 && !memcmp(result.c_str(), "0", 1))
{
(*AdminPasswordCallback) (request.AdminPassword);
}
}
#endif
while (!ElevatedServiceAvailable)
{
try
@ -396,6 +431,7 @@ namespace VeraCrypt
vector <char> adminPassword (request.AdminPassword.size() + 1);
int timeout = 6000;
// 'request.FastElevation' is always false under Linux / FreeBSD
if (request.FastElevation)
{
string dummyPassword = "dummy\n";
@ -457,6 +493,7 @@ namespace VeraCrypt
outPipe->Close();
errPipe.Close();
// 'request.FastElevation' is always false under Linux / FreeBSD
if (request.FastElevation)
{
// Prevent defunct process