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| author | Victoria Votokina <Victoria.Votokina@kaspersky.com> | 2025-10-10 13:52:40 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-29 14:07:05 +0100 |
| commit | 72427dc6f87523995f4e6ae35a948bb2992cabce (patch) | |
| tree | 7c6f448aaec7763635e24d0e54d19891eec03631 | |
| parent | 9a297a68c3ba4a7ecb31ed52f61bd6634abb79d3 (diff) | |
| download | linux-72427dc6f87523995f4e6ae35a948bb2992cabce.tar.gz linux-72427dc6f87523995f4e6ae35a948bb2992cabce.tar.bz2 linux-72427dc6f87523995f4e6ae35a948bb2992cabce.zip | |
most: usb: Fix use-after-free in hdm_disconnect
commit 4b1270902609ef0d935ed2faa2ea6d122bd148f5 upstream.
hdm_disconnect() calls most_deregister_interface(), which eventually
unregisters the MOST interface device with device_unregister(iface->dev).
If that drops the last reference, the device core may call release_mdev()
immediately while hdm_disconnect() is still executing.
The old code also freed several mdev-owned allocations in
hdm_disconnect() and then performed additional put_device() calls.
Depending on refcount order, this could lead to use-after-free or
double-free when release_mdev() ran (or when unregister paths also
performed puts).
Fix by moving the frees of mdev-owned allocations into release_mdev(),
so they happen exactly once when the device is truly released, and by
dropping the extra put_device() calls in hdm_disconnect() that are
redundant after device_unregister() and most_deregister_interface().
This addresses the KASAN slab-use-after-free reported by syzbot in
hdm_disconnect(). See report and stack traces in the bug link below.
Reported-by: syzbot+916742d5d24f6c254761@syzkaller.appspotmail.com
Cc: stable <stable@kernel.org>
Closes: https://syzkaller.appspot.com/bug?extid=916742d5d24f6c254761
Fixes: 97a6f772f36b ("drivers: most: add USB adapter driver")
Signed-off-by: Victoria Votokina <Victoria.Votokina@kaspersky.com>
Link: https://patch.msgid.link/20251010105241.4087114-2-Victoria.Votokina@kaspersky.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/most/most_usb.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/most/most_usb.c b/drivers/most/most_usb.c index 485d5ca39951..cafe36145f1c 100644 --- a/drivers/most/most_usb.c +++ b/drivers/most/most_usb.c @@ -929,6 +929,10 @@ static void release_mdev(struct device *dev) { struct most_dev *mdev = to_mdev_from_dev(dev); + kfree(mdev->busy_urbs); + kfree(mdev->cap); + kfree(mdev->conf); + kfree(mdev->ep_address); kfree(mdev); } /** @@ -1121,13 +1125,6 @@ static void hdm_disconnect(struct usb_interface *interface) if (mdev->dci) device_unregister(&mdev->dci->dev); most_deregister_interface(&mdev->iface); - - kfree(mdev->busy_urbs); - kfree(mdev->cap); - kfree(mdev->conf); - kfree(mdev->ep_address); - put_device(&mdev->dci->dev); - put_device(&mdev->dev); } static int hdm_suspend(struct usb_interface *interface, pm_message_t message) |