Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 003/113] vmci: type promotion bug in qp_host_get_user_memory()
Date:   Mon,  8 Oct 2018 20:30:04 +0200
Message-Id: <20181008175531.043550308@linuxfoundation.org>
In-Reply-To: <20181008175530.864641368@linuxfoundation.org>
References: <20181008175530.864641368@linuxfoundation.org>
User-Agent: quilt/0.65
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 7fb2fd4e25fc1fb10dcb30b5519de257cfeae84c ]

The problem is that if get_user_pages_fast() fails and returns a
negative error code, it gets type promoted to a high positive value and
treated as a success.

Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/misc/vmw_vmci/vmci_queue_pair.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -755,7 +755,7 @@ static int qp_host_get_user_memory(u64 p
 	retval = get_user_pages_fast((uintptr_t) produce_uva,
 				     produce_q->kernel_if->num_pages, 1,
 				     produce_q->kernel_if->u.h.header_page);
-	if (retval < produce_q->kernel_if->num_pages) {
+	if (retval < (int)produce_q->kernel_if->num_pages) {
 		pr_debug("get_user_pages_fast(produce) failed (retval=%d)",
 			retval);
 		qp_release_pages(produce_q->kernel_if->u.h.header_page,
@@ -767,7 +767,7 @@ static int qp_host_get_user_memory(u64 p
 	retval = get_user_pages_fast((uintptr_t) consume_uva,
 				     consume_q->kernel_if->num_pages, 1,
 				     consume_q->kernel_if->u.h.header_page);
-	if (retval < consume_q->kernel_if->num_pages) {
+	if (retval < (int)consume_q->kernel_if->num_pages) {
 		pr_debug("get_user_pages_fast(consume) failed (retval=%d)",
 			retval);
 		qp_release_pages(consume_q->kernel_if->u.h.header_page,