* Move killUser() to libutil so that the setuid helper can use it.

This commit is contained in:
Eelco Dolstra 2006-12-07 00:16:07 +00:00
parent 79875c5e42
commit 6a8e60913a
3 changed files with 82 additions and 51 deletions

View file

@ -352,6 +352,8 @@ public:
uid_t getUID();
uid_t getGID();
bool enabled();
};
@ -452,54 +454,27 @@ uid_t UserLock::getGID()
}
static void killUser(uid_t uid)
bool UserLock::enabled()
{
debug(format("killing all processes running under uid `%1%'") % uid);
assert(uid != rootUserId); /* just to be safe... */
/* The system call kill(-1, sig) sends the signal `sig' to all
users to which the current process can send signals. So we
fork a process, switch to uid, and send a mass kill. */
Pid pid;
pid = fork();
switch (pid) {
case -1:
throw SysError("unable to fork");
case 0:
try { /* child */
if (setuid(uid) == -1) abort();
while (true) {
if (kill(-1, SIGKILL) == 0) break;
if (errno == ESRCH) break; /* no more processes */
if (errno != EINTR)
throw SysError(format("cannot kill processes for uid `%1%'") % uid);
}
} catch (std::exception & e) {
std::cerr << format("killing processes beloging to uid `%1%': %1%\n")
% uid % e.what();
quickExit(1);
}
quickExit(0);
}
/* parent */
if (pid.wait(true) != 0)
throw Error(format("cannot kill processes for uid `%1%'") % uid);
/* !!! We should really do some check to make sure that there are
no processes left running under `uid', but there is no portable
way to do so (I think). The most reliable way may be `ps -eo
uid | grep -q $uid'. */
return uid != 0;
}
static bool amPrivileged()
{
return geteuid() == 0;
}
void killUserWrapped(uid_t uid)
{
if (amPrivileged())
killUser(uid);
else
/* !!! TODO */
printMsg(lvlError, "must kill");
}
//////////////////////////////////////////////////////////////////////
@ -825,8 +800,8 @@ void DerivationGoal::buildDone()
malicious user from leaving behind a process that keeps files
open and modifies them after they have been chown'ed to
root. */
if (buildUser.getUID() != 0)
killUser(buildUser.getUID());
if (buildUser.enabled())
killUserWrapped(buildUser.getUID());
/* Close the read side of the logger pipe. */
logPipe.readSide.close();
@ -1308,11 +1283,15 @@ void DerivationGoal::startBuilder()
/* Make sure that no other processes are executing under this
uid. */
killUser(buildUser.getUID());
killUserWrapped(buildUser.getUID());
/* Change ownership of the temporary build directory. !!! gid */
if (chown(tmpDir.c_str(), buildUser.getUID(), (gid_t) -1) == -1)
/* Change ownership of the temporary build directory, if we're
root. If we're not root, then the setuid helper will do it
just before it starts the builder. */
if (amPrivileged()) {
if (chown(tmpDir.c_str(), buildUser.getUID(), buildUser.getGID()) == -1)
throw SysError(format("cannot change ownership of `%1%'") % tmpDir);
}
/* Check that the Nix store has the appropriate permissions,
i.e., owned by root and mode 1775 (sticky bit on so that
@ -1325,7 +1304,7 @@ void DerivationGoal::startBuilder()
((st.st_mode & S_IRWXG) != S_IRWXG) ||
(st.st_gid != buildUser.getGID()))
throw Error(format(
"builder does not have write permission to `%1%'; "
"builder does not have write permission to `%2%'; "
"try `chgrp %1% %2%; chmod 1775 %2%'")
% buildUser.getGID() % nixStore);
}

View file

@ -707,6 +707,53 @@ void Pid::setSeparatePG(bool separatePG)
}
void killUser(uid_t uid)
{
debug(format("killing all processes running under uid `%1%'") % uid);
assert(uid != 0); /* just to be safe... */
/* The system call kill(-1, sig) sends the signal `sig' to all
users to which the current process can send signals. So we
fork a process, switch to uid, and send a mass kill. */
Pid pid;
pid = fork();
switch (pid) {
case -1:
throw SysError("unable to fork");
case 0:
try { /* child */
if (setuid(uid) == -1) abort();
while (true) {
if (kill(-1, SIGKILL) == 0) break;
if (errno == ESRCH) break; /* no more processes */
if (errno != EINTR)
throw SysError(format("cannot kill processes for uid `%1%'") % uid);
}
} catch (std::exception & e) {
std::cerr << format("killing processes beloging to uid `%1%': %1%\n")
% uid % e.what();
quickExit(1);
}
quickExit(0);
}
/* parent */
if (pid.wait(true) != 0)
throw Error(format("cannot kill processes for uid `%1%'") % uid);
/* !!! We should really do some check to make sure that there are
no processes left running under `uid', but there is no portable
way to do so (I think). The most reliable way may be `ps -eo
uid | grep -q $uid'. */
}
//////////////////////////////////////////////////////////////////////

View file

@ -224,6 +224,11 @@ public:
};
/* Kill all processes running under the specified uid by sending them
a SIGKILL. */
void killUser(uid_t uid);
/* Run a program and return its stdout in a string (i.e., like the
shell backtick operator). */
string runProgram(Path program);