[PATCH 2/6] sysvipc: Return EINVAL for invalid semctl commands

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

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 |  10 +++
 sysvipc/test-sysvipc.h           | 135 +++++++++++++++++++++++++++++++
 sysvipc/test-sysvsem.c           |   5 ++
 3 files changed, 150 insertions(+)
 create mode 100644 sysvipc/test-sysvipc.h

diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
index 1cdabde8f2..dcff6e691d 100644
--- a/sysdeps/unix/sysv/linux/semctl.c
+++ b/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;
diff --git a/sysvipc/test-sysvipc.h b/sysvipc/test-sysvipc.h
new file mode 100644
index 0000000000..86aa8df83d
--- /dev/null
+++ b/sysvipc/test-sysvipc.h
@@ -0,0 +1,135 @@
+/* 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 message queue.  */
+static inline int
+first_msg_invalid_cmd (void)
+{
+  const int msg_cmds[] = {
+    MSG_STAT,
+    MSG_INFO,
+#ifdef MSG_STAT_ANY
+    MSG_STAT_ANY,
+#endif
+  };
+
+  int invalid = first_common_invalid_cmd ();
+  for (int i = 0; i < array_length (msg_cmds); i++)
+    {
+      if (invalid == msg_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;
+}
+
+/* Return the first invalid command SysV IPC command for shared memory.  */
+static inline int
+first_shm_invalid_cmd (void)
+{
+  const int shm_cmds[] = {
+    SHM_STAT,
+    SHM_INFO,
+#ifdef SHM_STAT_ANY
+    SHM_STAT_ANY,
+#endif
+  };
+
+  int invalid = first_common_invalid_cmd ();
+  for (int i = 0; i < array_length (shm_cmds); i++)
+    {
+      if (invalid == shm_cmds[i])
+	{
+	  invalid++;
+	  i = 0;
+	}
+    }
+
+  return invalid;
+}
+
+#endif /* _TEST_SYSV_H  */
diff --git a/sysvipc/test-sysvsem.c b/sysvipc/test-sysvsem.c
index b7284e0b48..61837d8f3d 100644
--- a/sysvipc/test-sysvsem.c
+++ b/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)
-- 
2.25.1