From: ZhengHan Wang <[email protected]>
syzbot reports a slab use-after-free in hci_conn_hash_flush [1].
After releasing an object using hci_conn_del_sysfs in the
hci_conn_cleanup function, releasing the same object again
using the hci_dev_put and hci_conn_put functions causes a double free.
Here's a simplified flow:
hci_conn_del_sysfs:
hci_dev_put
put_device
kobject_put
kref_put
kobject_release
kobject_cleanup
kfree_const
kfree(name)
hci_dev_put:
...
kfree(name)
hci_conn_put:
put_device
...
kfree(name)
This patch drop the hci_dev_put and hci_conn_put function
call in hci_conn_cleanup function, because the object is
freed in hci_conn_del_sysfs function.
Link: https://syzkaller.appspot.com/bug?id=1bb51491ca5df96a5f724899d1dbb87afda61419 [1]
Signed-off-by: ZhengHan Wang <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
---
net/bluetooth/hci_conn.c | 6 ++----
net/bluetooth/hci_sysfs.c | 23 ++++++++++++-----------
2 files changed, 14 insertions(+), 15 deletions(-)
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index e4aee5950c36..00d1e7201a44 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -168,13 +168,11 @@ static void hci_conn_cleanup(struct hci_conn *conn)
hdev->notify(hdev, HCI_NOTIFY_CONN_DEL);
}
- hci_conn_del_sysfs(conn);
-
debugfs_remove_recursive(conn->debugfs);
- hci_dev_put(hdev);
+ hci_conn_del_sysfs(conn);
- hci_conn_put(conn);
+ hci_dev_put(hdev);
}
static void le_scan_cleanup(struct work_struct *work)
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 08542dfc2dc5..633b82d54272 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -33,7 +33,7 @@ void hci_conn_init_sysfs(struct hci_conn *conn)
{
struct hci_dev *hdev = conn->hdev;
- BT_DBG("conn %p", conn);
+ bt_dev_dbg(hdev, "conn %p", conn);
conn->dev.type = &bt_link;
conn->dev.class = bt_class;
@@ -46,27 +46,30 @@ void hci_conn_add_sysfs(struct hci_conn *conn)
{
struct hci_dev *hdev = conn->hdev;
- BT_DBG("conn %p", conn);
+ bt_dev_dbg(hdev, "conn %p", conn);
if (device_is_registered(&conn->dev))
return;
dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle);
- if (device_add(&conn->dev) < 0) {
+ if (device_add(&conn->dev) < 0)
bt_dev_err(hdev, "failed to register connection device");
- return;
- }
-
- hci_dev_hold(hdev);
}
void hci_conn_del_sysfs(struct hci_conn *conn)
{
struct hci_dev *hdev = conn->hdev;
- if (!device_is_registered(&conn->dev))
+ bt_dev_dbg(hdev, "conn %p", conn);
+
+ if (!device_is_registered(&conn->dev)) {
+ /* If device_add() has *not* succeeded, use *only* put_device()
+ * to drop the reference count.
+ */
+ put_device(&conn->dev);
return;
+ }
while (1) {
struct device *dev;
@@ -78,9 +81,7 @@ void hci_conn_del_sysfs(struct hci_conn *conn)
put_device(dev);
}
- device_del(&conn->dev);
-
- hci_dev_put(hdev);
+ device_unregister(&conn->dev);
}
static void bt_host_release(struct device *dev)
--
2.39.2
This is automated email and please do not reply to this email!
Dear submitter,
Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=735596
---Test result---
Test Summary:
CheckPatch PASS 0.75 seconds
GitLint FAIL 0.53 seconds
SubjectPrefix PASS 0.09 seconds
BuildKernel PASS 31.29 seconds
CheckAllWarning PASS 34.91 seconds
CheckSparse PASS 39.07 seconds
CheckSmatch PASS 108.89 seconds
BuildKernel32 PASS 30.34 seconds
TestRunnerSetup PASS 435.71 seconds
TestRunner_l2cap-tester PASS 16.15 seconds
TestRunner_iso-tester PASS 15.63 seconds
TestRunner_bnep-tester PASS 5.10 seconds
TestRunner_mgmt-tester PASS 106.90 seconds
TestRunner_rfcomm-tester PASS 8.21 seconds
TestRunner_sco-tester PASS 7.51 seconds
TestRunner_ioctl-tester PASS 8.72 seconds
TestRunner_mesh-tester PASS 6.37 seconds
TestRunner_smp-tester PASS 7.38 seconds
TestRunner_userchan-tester PASS 5.29 seconds
IncrementalBuild PASS 28.65 seconds
Details
##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
Bluetooth: Fix double free in hci_conn_cleanup
WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
34: B1 Line exceeds max length (87>80): "Link: https://syzkaller.appspot.com/bug?id=1bb51491ca5df96a5f724899d1dbb87afda61419 [1]"
---
Regards,
Linux Bluetooth
Do you think this might be the cause of
https://bugzilla.kernel.org/show_bug.cgi?id=201269 ?
Jay
On 3/30/23 3:02 PM, Luiz Augusto von Dentz wrote:
> From: ZhengHan Wang <[email protected]>
>
> syzbot reports a slab use-after-free in hci_conn_hash_flush [1].
> After releasing an object using hci_conn_del_sysfs in the
> hci_conn_cleanup function, releasing the same object again
> using the hci_dev_put and hci_conn_put functions causes a double free.
> Here's a simplified flow:
>
> hci_conn_del_sysfs:
> hci_dev_put
> put_device
> kobject_put
> kref_put
> kobject_release
> kobject_cleanup
> kfree_const
> kfree(name)
>
> hci_dev_put:
> ...
> kfree(name)
>
> hci_conn_put:
> put_device
> ...
> kfree(name)
>
> This patch drop the hci_dev_put and hci_conn_put function
> call in hci_conn_cleanup function, because the object is
> freed in hci_conn_del_sysfs function.
>
> Link: https://syzkaller.appspot.com/bug?id=1bb51491ca5df96a5f724899d1dbb87afda61419 [1]
>
> Signed-off-by: ZhengHan Wang <[email protected]>
> Signed-off-by: Luiz Augusto von Dentz <[email protected]>
> ---
> net/bluetooth/hci_conn.c | 6 ++----
> net/bluetooth/hci_sysfs.c | 23 ++++++++++++-----------
> 2 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
> index e4aee5950c36..00d1e7201a44 100644
> --- a/net/bluetooth/hci_conn.c
> +++ b/net/bluetooth/hci_conn.c
> @@ -168,13 +168,11 @@ static void hci_conn_cleanup(struct hci_conn *conn)
> hdev->notify(hdev, HCI_NOTIFY_CONN_DEL);
> }
>
> - hci_conn_del_sysfs(conn);
> -
> debugfs_remove_recursive(conn->debugfs);
>
> - hci_dev_put(hdev);
> + hci_conn_del_sysfs(conn);
>
> - hci_conn_put(conn);
> + hci_dev_put(hdev);
> }
>
> static void le_scan_cleanup(struct work_struct *work)
> diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
> index 08542dfc2dc5..633b82d54272 100644
> --- a/net/bluetooth/hci_sysfs.c
> +++ b/net/bluetooth/hci_sysfs.c
> @@ -33,7 +33,7 @@ void hci_conn_init_sysfs(struct hci_conn *conn)
> {
> struct hci_dev *hdev = conn->hdev;
>
> - BT_DBG("conn %p", conn);
> + bt_dev_dbg(hdev, "conn %p", conn);
>
> conn->dev.type = &bt_link;
> conn->dev.class = bt_class;
> @@ -46,27 +46,30 @@ void hci_conn_add_sysfs(struct hci_conn *conn)
> {
> struct hci_dev *hdev = conn->hdev;
>
> - BT_DBG("conn %p", conn);
> + bt_dev_dbg(hdev, "conn %p", conn);
>
> if (device_is_registered(&conn->dev))
> return;
>
> dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle);
>
> - if (device_add(&conn->dev) < 0) {
> + if (device_add(&conn->dev) < 0)
> bt_dev_err(hdev, "failed to register connection device");
> - return;
> - }
> -
> - hci_dev_hold(hdev);
> }
>
> void hci_conn_del_sysfs(struct hci_conn *conn)
> {
> struct hci_dev *hdev = conn->hdev;
>
> - if (!device_is_registered(&conn->dev))
> + bt_dev_dbg(hdev, "conn %p", conn);
> +
> + if (!device_is_registered(&conn->dev)) {
> + /* If device_add() has *not* succeeded, use *only* put_device()
> + * to drop the reference count.
> + */
> + put_device(&conn->dev);
> return;
> + }
>
> while (1) {
> struct device *dev;
> @@ -78,9 +81,7 @@ void hci_conn_del_sysfs(struct hci_conn *conn)
> put_device(dev);
> }
>
> - device_del(&conn->dev);
> -
> - hci_dev_put(hdev);
> + device_unregister(&conn->dev);
> }
>
> static void bt_host_release(struct device *dev)