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| author |   Thadeu Lima de Souza Cascardo <cascardo@canonical.com> | 2021-04-13 13:21:03 -0300 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-03 08:59:06 +0200 |
| commit | fe201316ac36c48fc3cb2891dfdc8ab68058734d (patch) | |
| tree | 0dfe6f390e9d745c06d715069e05c53dfff59e57 /net | |
| parent | spi: spi-geni-qcom: Fix use-after-free on unbind (diff) | |
| download | wireguard-linux-fe201316ac36c48fc3cb2891dfdc8ab68058734d.tar.xz wireguard-linux-fe201316ac36c48fc3cb2891dfdc8ab68058734d.zip | |
Bluetooth: cmtp: fix file refcount when cmtp_attach_device fails
commit 8da3a0b87f4f1c3a3bbc4bfb78cf68476e97d183 upstream.
When cmtp_attach_device fails, cmtp_add_connection returns the error value
which leads to the caller to doing fput through sockfd_put. But
cmtp_session kthread, which is stopped in this path will also call fput,
leading to a potential refcount underflow or a use-after-free.
Add a refcount before we signal the kthread to stop. The kthread will try
to grab the cmtp_session_sem mutex before doing the fput, which is held
when get_file is called, so there should be no races there.
Reported-by: Ryota Shiga
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/bluetooth/cmtp/core.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/bluetooth/cmtp/core.c b/net/bluetooth/cmtp/core.c index 07cfa3249f83..0a2d78e811cf 100644 --- a/net/bluetooth/cmtp/core.c +++ b/net/bluetooth/cmtp/core.c @@ -392,6 +392,11 @@ int cmtp_add_connection(struct cmtp_connadd_req *req, struct socket *sock) if (!(session->flags & BIT(CMTP_LOOPBACK))) { err = cmtp_attach_device(session); if (err < 0) { + /* Caller will call fput in case of failure, and so + * will cmtp_session kthread. + */ + get_file(session->sock->file); + atomic_inc(&session->terminate); wake_up_interruptible(sk_sleep(session->sock->sk)); up_write(&cmtp_session_sem); |