Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Matthew Wilcox <willy@infradead.org>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 621/779] s390/crash: fix incorrect number of bytes to copy to user space
Date:   Mon, 15 Aug 2022 20:04:25 +0200
Message-Id: <20220815180403.929995313@linuxfoundation.org>
In-Reply-To: <20220815180337.130757997@linuxfoundation.org>
References: <20220815180337.130757997@linuxfoundation.org>
User-Agent: quilt/0.67
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Alexander Gordeev <agordeev@linux.ibm.com>

[ Upstream commit f6749da17a34eb08c9665f072ce7c812ff68aad2 ]

The number of bytes in a chunk is correctly calculated, but instead
the total number of bytes is passed to copy_to_user_real() function.

Reported-by: Matthew Wilcox <willy@infradead.org>
Fixes: df9694c7975f ("s390/dump: streamline oldmem copy functions")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/kernel/crash_dump.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 199f136d1644..f17ad2daab07 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -198,7 +198,7 @@ static int copy_oldmem_user(void __user *dst, unsigned long src, size_t count)
 			} else {
 				len = count;
 			}
-			rc = copy_to_user_real(dst, src, count);
+			rc = copy_to_user_real(dst, src, len);
 			if (rc)
 				return rc;
 		}
-- 
2.35.1