kernel: Do not use gSchedulerLock when accesing UID and GID

Reads and writes to uid_t and gid_t are atomic anyway. The only real
problem that may happen here is inconsistent state of triples
effective_{u, g}id, saved_set_{u, g}id, real_{u, g}id, but team locks
protect us against that.

src/system/kernel/signal.cpp

@@ -315,7 +315,6 @@ Signal::SetTo(uint32 number)
 	fErrorCode = 0;
 	fSendingProcess = team->id;
 	fSendingUser = team->effective_uid;
-		// assuming scheduler lock is being held
 	fStatus = 0;
 	fPollBand = 0;
 	fAddress = NULL;
@@ -1322,19 +1321,13 @@ has_signals_pending(Thread* thread)
 /*!	Checks whether the current user has permission to send a signal to the given
 	target team.
 
-	The caller must hold the scheduler lock or \a team's lock.
-
 	\param team The target team.
-	\param schedulerLocked \c true, if the caller holds the scheduler lock,
-		\c false otherwise.
 */
 static bool
-has_permission_to_signal(Team* team, bool schedulerLocked)
+has_permission_to_signal(Signal* signal, Team* team)
 {
 	// get the current user
-	uid_t currentUser = schedulerLocked
-		? thread_get_current_thread()->team->effective_uid
-		: geteuid();
+	uid_t currentUser = signal->SendingUser();
 
 	// root is omnipotent -- in the other cases the current user must match the
 	// target team's
@@ -1372,7 +1365,7 @@ send_signal_to_thread_locked(Thread* thread, uint32 signalNumber,
 	BReference<Signal> signalReference(signal, true);
 
 	if ((flags & B_CHECK_PERMISSION) != 0) {
-		if (!has_permission_to_signal(thread->team, true))
+		if (!has_permission_to_signal(signal, thread->team))
 			return EPERM;
 	}
 
@@ -1566,7 +1559,7 @@ send_signal_to_team_locked(Team* team, uint32 signalNumber, Signal* signal,
 	BReference<Signal> signalReference(signal, true);
 
 	if ((flags & B_CHECK_PERMISSION) != 0) {
-		if (!has_permission_to_signal(team, true))
+		if (!has_permission_to_signal(signal, team))
 			return EPERM;
 	}
 

src/system/kernel/usergroup.cpp

@@ -54,7 +54,6 @@ common_setregid(gid_t rgid, gid_t egid, bool setAllIfPrivileged, bool kernel)
 			// setgid() semantics: If privileged set both, real, effective and
 			// saved set-gid, otherwise set the effective gid.
 			if (privileged) {
-				InterruptsSpinLocker schedulerLocker(gSchedulerLock);
 				team->saved_set_gid = rgid;
 				team->real_gid = rgid;
 				team->effective_gid = rgid;
@@ -91,7 +90,6 @@ common_setregid(gid_t rgid, gid_t egid, bool setAllIfPrivileged, bool kernel)
 	}
 
 	// Getting here means all checks were successful -- set the gids.
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
 	team->real_gid = rgid;
 	team->effective_gid = egid;
 	team->saved_set_gid = ssgid;
@@ -119,7 +117,6 @@ common_setreuid(uid_t ruid, uid_t euid, bool setAllIfPrivileged, bool kernel)
 			// setuid() semantics: If privileged set both, real, effective and
 			// saved set-uid, otherwise set the effective uid.
 			if (privileged) {
-				InterruptsSpinLocker schedulerLocker(gSchedulerLock);
 				team->saved_set_uid = ruid;
 				team->real_uid = ruid;
 				team->effective_uid = ruid;
@@ -156,7 +153,6 @@ common_setreuid(uid_t ruid, uid_t euid, bool setAllIfPrivileged, bool kernel)
 	}
 
 	// Getting here means all checks were successful -- set the uids.
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
 	team->real_uid = ruid;
 	team->effective_uid = euid;
 	team->saved_set_uid = ssuid;
@@ -253,8 +249,6 @@ common_setgroups(int groupCount, const gid_t* groupList, bool kernel)
 void
 inherit_parent_user_and_group(Team* team, Team* parent)
 {
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
-
 	team->saved_set_uid = parent->saved_set_uid;
 	team->real_uid = parent->real_uid;
 	team->effective_uid = parent->effective_uid;
@@ -262,8 +256,6 @@ inherit_parent_user_and_group(Team* team, Team* parent)
 	team->real_gid = parent->real_gid;
 	team->effective_gid = parent->effective_gid;
 
-	schedulerLocker.Unlock();
-
 	malloc_referenced_acquire(parent->supplementary_groups);
 	team->supplementary_groups = parent->supplementary_groups;
 	team->supplementary_group_count = parent->supplementary_group_count;
@@ -279,7 +271,6 @@ update_set_id_user_and_group(Team* team, const char* file)
 		return status;
 
 	TeamLocker teamLocker(team);
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
 
 	if ((st.st_mode & S_ISUID) != 0) {
 		team->saved_set_uid = st.st_uid;
@@ -300,8 +291,6 @@ _kern_getgid(bool effective)
 {
 	Team* team = thread_get_current_thread()->team;
 
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
-
 	return effective ? team->effective_gid : team->real_gid;
 }
 
@@ -311,8 +300,6 @@ _kern_getuid(bool effective)
 {
 	Team* team = thread_get_current_thread()->team;
 
-	InterruptsSpinLocker schedulerLocker(gSchedulerLock);
-
 	return effective ? team->effective_uid : team->real_uid;
 }
 
@@ -353,8 +340,6 @@ _user_getgid(bool effective)
 {
 	Team* team = thread_get_current_thread()->team;
 
-	TeamLocker teamLocker(team);
-
 	return effective ? team->effective_gid : team->real_gid;
 }
 
@@ -364,8 +349,6 @@ _user_getuid(bool effective)
 {
 	Team* team = thread_get_current_thread()->team;
 
-	TeamLocker teamLocker(team);
-
 	return effective ? team->effective_uid : team->real_uid;
 }
 
@@ -395,12 +378,9 @@ ssize_t
 _user_setgroups(int groupCount, const gid_t* groupList)
 {
 	// check privilege
-	{
-		Team* team = thread_get_current_thread()->team;
-		TeamLocker teamLocker(team);
-		if (!is_privileged(team))
-			return EPERM;
-	}
+	Team* team = thread_get_current_thread()->team;
+	if (!is_privileged(team))
+		return EPERM;
 
 	return common_setgroups(groupCount, groupList, false);
 }