sysvipc: Return EINVAL for invalid semctl commands

It avoids regressions on possible future commands that might require
additional libc support.  The downside is new commands added by newer
kernels will need further glibc support.

Checked on x86_64-linux-gnu and i686-linux-gnu (Linux v4.15 and v5.4).

sysdeps/unix/sysv/linux/semctl.c

@@ -158,6 +158,15 @@ __semctl64 (int semid, int semnum, int cmd, ...)
       arg64 = va_arg (ap, union semun64);
       va_end (ap);
       break;
+    case IPC_RMID:      /* arg ignored.  */
+    case GETNCNT:
+    case GETPID:
+    case GETVAL:
+    case GETZCNT:
+      break;
+    default:
+      __set_errno (EINVAL);
+      return -1;
     }
 
 #if __IPC_TIME64
@@ -277,6 +286,7 @@ __semctl (int semid, int semnum, int cmd, ...)
       arg = va_arg (ap, union semun);
       va_end (ap);
       break;
+    /* __semctl64 handles non-supported commands.  */
     }
 
   struct __semid64_ds semid64;

sysvipc/test-sysvipc.h

@@ -0,0 +1,85 @@
+/* Basic definition for Sysv IPC test functions.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _TEST_SYSV_H
+#define _TEST_SYSV_H
+
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/msg.h>
+#include <sys/shm.h>
+#include <include/array_length.h>
+
+/* Return the first invalid command SysV IPC command from common shared
+   between message queue, shared memory, and semaphore.  */
+static inline int
+first_common_invalid_cmd (void)
+{
+  const int common_cmds[] = {
+    IPC_RMID,
+    IPC_SET,
+    IPC_STAT,
+    IPC_INFO,
+  };
+
+  int invalid = 0;
+  for (int i = 0; i < array_length (common_cmds); i++)
+    {
+      if (invalid == common_cmds[i])
+	{
+	  invalid++;
+	  i = 0;
+        }
+    }
+
+  return invalid;
+}
+
+/* Return the first invalid command SysV IPC command for semaphore.  */
+static inline int
+first_sem_invalid_cmd (void)
+{
+  const int sem_cmds[] = {
+    GETPID,
+    GETVAL,
+    GETALL,
+    GETNCNT,
+    GETZCNT,
+    SETVAL,
+    SETALL,
+    SEM_STAT,
+    SEM_INFO,
+#ifdef SEM_STAT_ANY
+    SEM_STAT_ANY,
+#endif
+  };
+
+  int invalid = first_common_invalid_cmd ();
+  for (int i = 0; i < array_length (sem_cmds); i++)
+    {
+      if (invalid == sem_cmds[i])
+	{
+	  invalid++;
+	  i = 0;
+	}
+    }
+
+  return invalid;
+}
+
+#endif /* _TEST_SYSV_H  */

sysvipc/test-sysvsem.c

@@ -25,6 +25,8 @@
 #include <sys/ipc.h>
 #include <sys/sem.h>
 
+#include <test-sysvipc.h>
+
 #include <support/support.h>
 #include <support/check.h>
 #include <support/temp_file.h>
@@ -80,6 +82,9 @@ do_test (void)
       FAIL_EXIT1 ("semget failed (errno=%d)", errno);
     }
 
+  TEST_COMPARE (semctl (semid, 0, first_sem_invalid_cmd (), NULL), -1);
+  TEST_COMPARE (errno, EINVAL);
+
   /* Get semaphore kernel information and do some sanity checks.  */
   struct semid_ds seminfo;
   if (semctl (semid, 0, IPC_STAT, (union semun) { .buf = &seminfo }) == -1)