From 58aff0af757356065f33290d96a9cd46dfbcae88 Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Mon, 18 Sep 2017 17:47:38 +0100
Subject: [PATCH] ipc/shm: Fix order of parameters when calling
copy_compat_shmid_to_user
Commit 553f770ef71b ("ipc: move compat shmctl to native") moved the
compat IPC syscall handling into ipc/shm.c and refactored the struct
accessors in the process. Unfortunately, the call to
copy_compat_shmid_to_user when handling a compat {IPC,SHM}_STAT command
gets the arguments the wrong way round, passing a kernel stack address
as the user buffer (destination) and the user buffer as the kernel stack
address (source).
This patch fixes the parameter ordering so the buffers are accessed
correctly.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
ipc/shm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ipc/shm.c b/ipc/shm.c
index 1b3adfe3c60e2..1e2b1692ba2c6 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1237,7 +1237,7 @@ COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
err = shmctl_stat(ns, shmid, cmd, &sem64);
if (err < 0)
return err;
- if (copy_compat_shmid_to_user(&sem64, uptr, version))
+ if (copy_compat_shmid_to_user(uptr, &sem64, version))
err = -EFAULT;
return err;
--
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