Merge pull request #6103 from sudo-sturbia:semaphore-err

PiperOrigin-RevId: 378607458

2 files changed, 19 insertions, 2 deletions

diff --git a/pkg/sentry/kernel/semaphore/semaphore.go b/pkg/sentry/kernel/semaphore/semaphore.go
index 1d9edf118..47bb66b42 100644
--- a/pkg/sentry/kernel/semaphore/semaphore.go
+++ b/pkg/sentry/kernel/semaphore/semaphore.go
@@ -171,10 +171,10 @@ func (r *Registry) FindOrCreate(ctx context.Context, key, nsems int32, mode linu
 	// Map semaphores and map indexes in a registry are of the same size,
 	// check map semaphores only here for the system limit.
 	if len(r.semaphores) >= setsMax {
-		return nil, syserror.EINVAL
+		return nil, syserror.ENOSPC
 	}
 	if r.totalSems() > int(semsTotalMax-nsems) {
-		return nil, syserror.EINVAL
+		return nil, syserror.ENOSPC
 	}
 
 	// Finally create a new set.
diff --git a/test/syscalls/linux/semaphore.cc b/test/syscalls/linux/semaphore.cc
index 2ce8f836c..f72957f89 100644
--- a/test/syscalls/linux/semaphore.cc
+++ b/test/syscalls/linux/semaphore.cc
@@ -49,6 +49,9 @@ constexpr int kSemAem = 32767;
 
 class AutoSem {
  public:
+  // Creates a new private semaphore.
+  AutoSem() : id_(semget(IPC_PRIVATE, 1, 0)) {}
+
   explicit AutoSem(int id) : id_(id) {}
   ~AutoSem() {
     if (id_ >= 0) {
@@ -101,6 +104,20 @@ TEST(SemaphoreTest, SemGet) {
   EXPECT_NE(sem3.get(), sem2.get());
 }
 
+// Tests system-wide limits for semget.
+TEST(SemaphoreTest, SemGetSystemLimits) {
+  // Disable save so that we don't trigger save/restore too many times.
+  const DisableSave ds;
+
+  // Exceed number of semaphores per set.
+  EXPECT_THAT(semget(IPC_PRIVATE, kSemMsl + 1, 0),
+              SyscallFailsWithErrno(EINVAL));
+
+  // Exceed system-wide limit for semaphore sets by 1.
+  AutoSem sems[kSemMni];
+  EXPECT_THAT(semget(IPC_PRIVATE, 1, 0), SyscallFailsWithErrno(ENOSPC));
+}
+
 // Tests simple operations that shouldn't block in a single-thread.
 TEST(SemaphoreTest, SemOpSingleNoBlock) {
   AutoSem sem(semget(IPC_PRIVATE, 1, 0600 | IPC_CREAT));