From 275f22148e8720e84b180d9e0cdf8abfd69bac5b Mon Sep 17 00:00:00 2001
From: Arnd Bergmann
Date: Mon, 31 Dec 2018 22:22:40 +0100
Subject: ipc: rename old-style shmctl/semctl/msgctl syscalls

The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.

For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.

The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.

As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same thing now,
but simply won't get called on architectures with the modern interface.

A small downside is that on architectures that do set
ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points
that are never called. They only add a few bytes of bloat, so it seems
better to keep them compared to adding yet another Kconfig symbol.
I considered adding new syscall numbers for the IPC_64 variants for
consistency, but decided against that for now.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 ipc/msg.c | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

(limited to 'ipc/msg.c')

diff --git a/ipc/msg.c b/ipc/msg.c
index 0833c6405915..8dec945fa030 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -567,9 +567,8 @@ out_unlock:
 	return err;
 }
 
-long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
+static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
 {
-	int version;
 	struct ipc_namespace *ns;
 	struct msqid64_ds msqid64;
 	int err;
@@ -577,7 +576,6 @@ long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
 	if (msqid < 0 || cmd < 0)
 		return -EINVAL;
 
-	version = ipc_parse_version(&cmd);
 	ns = current->nsproxy->ipc_ns;
 
 	switch (cmd) {
@@ -613,9 +611,23 @@ long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
 
 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
 {
-	return ksys_msgctl(msqid, cmd, buf);
+	return ksys_msgctl(msqid, cmd, buf, IPC_64);
 }
 
+#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
+long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
+{
+	int version = ipc_parse_version(&cmd);
+
+	return ksys_msgctl(msqid, cmd, buf, version);
+}
+
+SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
+{
+	return ksys_old_msgctl(msqid, cmd, buf);
+}
+#endif
+
 #ifdef CONFIG_COMPAT
 
 struct compat_msqid_ds {
@@ -689,12 +701,11 @@ static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
 	}
 }
 
-long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr)
+static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
 {
 	struct ipc_namespace *ns;
 	int err;
 	struct msqid64_ds msqid64;
-	int version = compat_ipc_parse_version(&cmd);
 
 	ns = current->nsproxy->ipc_ns;
 
@@ -734,8 +745,22 @@ long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr)
 
 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
 {
-	return compat_ksys_msgctl(msqid, cmd, uptr);
+	return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
 }
+
+#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
+long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
+{
+	int version = compat_ipc_parse_version(&cmd);
+
+	return compat_ksys_msgctl(msqid, cmd, uptr, version);
+}
+
+COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
+{
+	return compat_ksys_old_msgctl(msqid, cmd, uptr);
+}
+#endif
 #endif
 
 static int testmsg(struct msg_msg *msg, long type, int mode)
-- 
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