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bluetooth: fix leak of uninitialized data to userspace

PATCH In review Vegard Nossum 2 participants 2 messages Oct 5, 2008 Bluetooth

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Vegard Nossum

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#0 lore raw

PATCH 1/1 bluetooth: fix leak of uninitialized data to userspace

Quoted 1 line

From 45be27894a18f87b71b855fcc4afd50f860254b4 Mon Sep 17 00:00:00 2001

From: Vegard Nossum <[email protected]>
Date: Sun, 5 Oct 2008 17:25:45 +0200
Subject: [PATCH] bluetooth: fix leak of uninitialized data to userspace

    struct hci_dev_list_req {
            __u16  dev_num;
            struct hci_dev_req dev_req[0];  /* hci_dev_req structures */
    };

sizeof(struct hci_dev_list_req) == 4, so the two bytes immediately following "dev_num" will never be initialized. When this structure is copied to userspace, these uninitialized bytes are leaked.

Fix by using kzalloc() instead of kmalloc(). Found using kmemcheck.

Signed-off-by Vegard Nossum <[email protected]>
---
 net/bluetooth/hci_core.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
net/bluetooth/hci_core.c +1 -1
index 278a3ac..7bb0f1c 100644
@@ -756,7 +756,7 @@ int hci_get_dev_list(void __user *arg)
 
 	size = sizeof(*dl) + dev_num * sizeof(*dr);
 
-	if (!(dl = kmalloc(size, GFP_KERNEL)))
+	if (!(dl = kzalloc(size, GFP_KERNEL)))
 		return -ENOMEM;
 
 	dr = dl->dev_req;
Signature · 1 line
1.5.5.1
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#1 lore raw

Hi Vegard,

Quoted 10 lines

From 45be27894a18f87b71b855fcc4afd50f860254b4 Mon Sep 17 00:00:00 2001
From: Vegard Nossum <[email protected]>
Date: Sun, 5 Oct 2008 17:25:45 +0200
Subject: [PATCH] bluetooth: fix leak of uninitialized data to userspace

    struct hci_dev_list_req {
            __u16  dev_num;
            struct hci_dev_req dev_req[0];  /* hci_dev_req structures */
    };
Quoted 5 lines

sizeof(struct hci_dev_list_req) == 4, so the two bytes immediately following "dev_num" will never be initialized. When this structure is copied to userspace, these uninitialized bytes are leaked.

Fix by using kzalloc() instead of kmalloc(). Found using kmemcheck.

good catch. I thought we moved everything over to kzalloc, but as it seems we forgot at least one. Applied your patch to me tree. Thanks.

Regards

Marcel