linux-kernel - [PATCH] video/fbdev: Fix a double free in hvfb

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20210323073350.17697-1-lyl2019@mail.ustc.edu.cn>
Date:   Tue, 23 Mar 2021 00:33:50 -0700
From:   Lv Yunlong <lyl2019@...l.ustc.edu.cn>
To:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        wei.liu@...nel.org
Cc:     linux-hyperv@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Lv Yunlong <lyl2019@...l.ustc.edu.cn>
Subject: [PATCH] video/fbdev: Fix a double free in hvfb_probe

In function hvfb_probe in hyperv_fb.c, it calls hvfb_getmem(hdev, info)
and return err when info->apertures is freed.

In the error1 label of hvfb_probe, info->apertures will be freed twice
by framebuffer_release(info).

My patch sets info->apertures to NULL after it was freed to avoid
double free.

Signed-off-by: Lv Yunlong <lyl2019@...l.ustc.edu.cn>
---
 drivers/video/fbdev/hyperv_fb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index c8b0ae676809..2fc9b507e73a 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -1032,6 +1032,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
 		if (!pdev) {
 			pr_err("Unable to find PCI Hyper-V video\n");
 			kfree(info->apertures);
+			info->apertures = NULL;
 			return -ENODEV;
 		}
 
@@ -1130,6 +1131,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
 		pci_dev_put(pdev);
 	}
 	kfree(info->apertures);
+	info->apertures = NULL;
 
 	return 0;
 
@@ -1142,6 +1144,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
 	if (!gen2vm)
 		pci_dev_put(pdev);
 	kfree(info->apertures);
+	info->apertures = NULL;
 
 	return -ENOMEM;
 }
-- 
2.25.1