linux-kernel - [PATCH] VMCI: check return value of get_user_pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20200825164522.412392-1-alex.dewar90@gmail.com>
Date:   Tue, 25 Aug 2020 17:45:18 +0100
From:   Alex Dewar <alex.dewar90@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Dewar <alex.dewar90@...il.com>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy king <acking@...are.com>,
        George Zhang <georgezhang@...are.com>,
        Dmitry Torokhov <dtor@...are.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] VMCI: check return value of get_user_pages_fast() for errors

In a couple of places in qp_host_get_user_memory(),
get_user_pages_fast() is called without properly checking for errors. If
e.g. -EFAULT is returned, this negative value will then be passed on to
qp_release_pages(), which expects a u64 as input.

Fix this by only calling qp_release_pages() when we have a positive
number returned.

Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.")
Signed-off-by: Alex Dewar <alex.dewar90@...il.com>
---
 drivers/misc/vmw_vmci/vmci_queue_pair.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index 8531ae781195..c49065887e8f 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -657,8 +657,9 @@ static int qp_host_get_user_memory(u64 produce_uva,
 	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,
-				 retval, false);
+		if (retval > 0)
+			qp_release_pages(produce_q->kernel_if->u.h.header_page,
+					retval, false);
 		err = VMCI_ERROR_NO_MEM;
 		goto out;
 	}
@@ -670,8 +671,9 @@ static int qp_host_get_user_memory(u64 produce_uva,
 	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,
-				 retval, false);
+		if (retval > 0)
+			qp_release_pages(consume_q->kernel_if->u.h.header_page,
+					retval, false);
 		qp_release_pages(produce_q->kernel_if->u.h.header_page,
 				 produce_q->kernel_if->num_pages, false);
 		err = VMCI_ERROR_NO_MEM;
-- 
2.28.0