sysvipc: Fix IPC_INFO and MSG_INFO handling [BZ #26639]

Both commands are Linux extensions where the third argument is a
'struct msginfo' instead of 'struct msqid_ds' and its information
does not contain any time related fields (so there is no need to
extra conversion for __IPC_TIME64.

The regression testcase checks for Linux specifix SysV ipc message
control extension.  For IPC_INFO/MSG_INFO it tries to match the values
against the tunable /proc values and for MSG_STAT/MSG_STAT_ANY it
check if the create message queue is within the global list returned
by the kernel.

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

1 files changed, 18 insertions, 4 deletions

diff --git a/sysdeps/unix/sysv/linux/msgctl.c b/sysdeps/unix/sysv/linux/msgctl.c
index 0776472d5e..a1f24ab242 100644
--- a/sysdeps/unix/sysv/linux/msgctl.c
+++ b/sysdeps/unix/sysv/linux/msgctl.c
@@ -90,8 +90,15 @@ __msgctl64 (int msqid, int cmd, struct __msqid64_ds *buf)
   struct kernel_msqid64_ds ksemid, *arg = NULL;
   if (buf != NULL)
     {
-      msqid64_to_kmsqid64 (buf, &ksemid);
-      arg = &ksemid;
+      /* This is a Linux extension where kernel returns a 'struct msginfo'
+	 instead.  */
+      if (cmd == IPC_INFO || cmd == MSG_INFO)
+	arg = (struct kernel_msqid64_ds *) buf;
+      else
+	{
+	  msqid64_to_kmsqid64 (buf, &ksemid);
+	  arg = &ksemid;
+	}
     }
 # ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
   if (cmd == IPC_SET)
@@ -169,8 +176,15 @@ __msgctl (int msqid, int cmd, struct msqid_ds *buf)
   struct __msqid64_ds msqid64, *buf64 = NULL;
   if (buf != NULL)
     {
-      msqid_to_msqid64 (&msqid64, buf);
-      buf64 = &msqid64;
+      /* This is a Linux extension where kernel returns a 'struct msginfo'
+	 instead.  */
+      if (cmd == IPC_INFO || cmd == MSG_INFO)
+	buf64 = (struct __msqid64_ds *) buf;
+      else
+	{
+	  msqid_to_msqid64 (&msqid64, buf);
+	  buf64 = &msqid64;
+	}
     }
 
   int ret = __msgctl64 (msqid, cmd, buf64);