[PATCH 05/10] vhost-backend: avoid overflow on memslots_limit

From: Roman Kagan <rvkagan@yandex-team.ru>
To: qemu-devel@nongnu.org
Cc: "Kevin Wolf" <kwolf@redhat.com>,
	qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	"Raphael Norwitz" <raphael.norwitz@nutanix.com>,
	"Hanna Reitz" <hreitz@redhat.com>,
	yc-core@yandex-team.ru,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>
Subject: [PATCH 05/10] vhost-backend: avoid overflow on memslots_limit
Date: Thu, 11 Nov 2021 18:33:49 +0300	[thread overview]
Message-ID: <20211111153354.18807-6-rvkagan@yandex-team.ru> (raw)
In-Reply-To: <20211111153354.18807-1-rvkagan@yandex-team.ru>

Fix the (hypothetical) potential problem when the value parsed out of
the vhost module parameter in sysfs overflows the return value from
vhost_kernel_memslots_limit.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
---
 hw/virtio/vhost-backend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index b65f8f7e97..44f7dbb243 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
     if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions",
                             &s, NULL, NULL)) {
         uint64_t val = g_ascii_strtoull(s, NULL, 10);
-        if (!((val == G_MAXUINT64 || !val) && errno)) {
+        if (val < INT_MAX && val > 0) {
             g_free(s);
             return val;
         }
-- 
2.33.1


