[PATCH] kernel: Return -EFAULT if copy_to_user() fails

From: Wang Qing <wangqing@vivo.com>
To: Christian Brauner <christian.brauner@ubuntu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Thomas Cedeno <thomascedeno@google.com>,
	Nicolas Viennot <Nicolas.Viennot@twosigma.com>,
	Michel Lespinasse <walken@google.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Gabriel Krisman Bertazi <krisman@collabora.com>,
	linux-kernel@vger.kernel.org
Cc: Wang Qing <wangqing@vivo.com>
Subject: [PATCH] kernel: Return -EFAULT if copy_to_user() fails
Date: Mon,  1 Mar 2021 19:28:11 +0800	[thread overview]
Message-ID: <1614598093-1188-1-git-send-email-wangqing@vivo.com> (raw)

The copy_to_user() function returns the number of bytes remaining to be
copied, but we want to return -EFAULT if the copy doesn't complete.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 kernel/sys.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index 8bb46e5..d97a84a
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1247,7 +1247,7 @@ static int override_release(char __user *release, size_t len)
 		copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
 		ret = copy_to_user(release, buf, copy + 1);
 	}
-	return ret;
+	return ret ? -EFAULT : 0;
 }
 
 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
-- 
2.7.4

