From 20bc2a3aff5a88a666e81182fd277ea2a521fd3d Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 9 Jul 2017 10:27:22 -0400
Subject: ipc(2): move compat to native

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 ipc/syscall.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 89 insertions(+), 1 deletion(-)

(limited to 'ipc/syscall.c')

diff --git a/ipc/syscall.c b/ipc/syscall.c
index 52429489cde0..667022746ca5 100644
--- a/ipc/syscall.c
+++ b/ipc/syscall.c
@@ -5,12 +5,12 @@
  * the individual syscalls instead.
  */
 #include <linux/unistd.h>
+#include <linux/syscalls.h>
 
 #ifdef __ARCH_WANT_SYS_IPC
 #include <linux/errno.h>
 #include <linux/ipc.h>
 #include <linux/shm.h>
-#include <linux/syscalls.h>
 #include <linux/uaccess.h>
 
 SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
@@ -97,3 +97,91 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
 	}
 }
 #endif
+
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+#ifndef COMPAT_SHMLBA
+#define COMPAT_SHMLBA	SHMLBA
+#endif
+
+struct compat_ipc_kludge {
+	compat_uptr_t msgp;
+	compat_long_t msgtyp;
+};
+
+#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
+COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
+	u32, third, compat_uptr_t, ptr, u32, fifth)
+{
+	int version;
+	u32 pad;
+
+	version = call >> 16; /* hack for backward compatibility */
+	call &= 0xffff;
+
+	switch (call) {
+	case SEMOP:
+		/* struct sembuf is the same on 32 and 64bit :)) */
+		return sys_semtimedop(first, compat_ptr(ptr), second, NULL);
+	case SEMTIMEDOP:
+		return compat_sys_semtimedop(first, compat_ptr(ptr), second,
+						compat_ptr(fifth));
+	case SEMGET:
+		return sys_semget(first, second, third);
+	case SEMCTL:
+		if (!ptr)
+			return -EINVAL;
+		if (get_user(pad, (u32 __user *) compat_ptr(ptr)))
+			return -EFAULT;
+		return compat_sys_semctl(first, second, third, pad);
+
+	case MSGSND:
+		return compat_sys_msgsnd(first, ptr, second, third);
+
+	case MSGRCV: {
+		void __user *uptr = compat_ptr(ptr);
+
+		if (first < 0 || second < 0)
+			return -EINVAL;
+
+		if (!version) {
+			struct compat_ipc_kludge ipck;
+			if (!uptr)
+				return -EINVAL;
+			if (copy_from_user(&ipck, uptr, sizeof(ipck)))
+				return -EFAULT;
+			return compat_sys_msgrcv(first, ipck.msgp, second,
+						 ipck.msgtyp, third);
+		}
+		return compat_sys_msgrcv(first, ptr, second, fifth, third);
+	}
+	case MSGGET:
+		return sys_msgget(first, second);
+	case MSGCTL:
+		return compat_sys_msgctl(first, second, compat_ptr(ptr));
+
+	case SHMAT: {
+		int err;
+		unsigned long raddr;
+
+		if (version == 1)
+			return -EINVAL;
+		err = do_shmat(first, compat_ptr(ptr), second, &raddr,
+			       COMPAT_SHMLBA);
+		if (err < 0)
+			return err;
+		return put_user(raddr, (compat_ulong_t *)compat_ptr(third));
+	}
+	case SHMDT:
+		return sys_shmdt(compat_ptr(ptr));
+	case SHMGET:
+		return sys_shmget(first, (unsigned)second, third);
+	case SHMCTL:
+		return compat_sys_shmctl(first, second, compat_ptr(ptr));
+	}
+
+	return -ENOSYS;
+}
+#endif
+#endif
-- 
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