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commit 9380afd6df70e24eacbdbde33afc6a3950965d22 upstream.
usbip_sockfd_store() is invoked when user requests attach (import)
detach (unimport) usb device from usbip host. vhci_hcd sends import
request and usbip_sockfd_store() exports the device if it is free
for export.
Export and unexport are governed by local state and shared state
- Shared state (usbip device status, sockfd) - sockfd and Device
status are used to determine if stub should be brought up or shut
down.
- Local state (tcp_socket, rx and tx thread task_struct ptrs)
A valid tcp_socket controls rx and tx thread operations while the
device is in exported state.
- While the device is exported, device status is marked used and socket,
sockfd, and thread pointers are valid.
Export sequence (stub-up) includes validating the socket and creating
receive (rx) and transmit (tx) threads to talk to the client to provide
access to the exported device. rx and tx threads depends on local and
shared state to be correct and in sync.
Unexport (stub-down) sequence shuts the socket down and stops the rx and
tx threads. Stub-down sequence relies on local and shared states to be
in sync.
There are races in updating the local and shared status in the current
stub-up sequence resulting in crashes. These stem from starting rx and
tx threads before local and global state is updated correctly to be in
sync.
1. Doesn't handle kthread_create() error and saves invalid ptr in local
state that drives rx and tx threads.
2. Updates tcp_socket and sockfd, starts stub_rx and stub_tx threads
before updating usbip_device status to SDEV_ST_USED. This opens up a
race condition between the threads and usbip_sockfd_store() stub up
and down handling.
Fix the above problems:
- Stop using kthread_get_run() macro to create/start threads.
- Create threads and get task struct reference.
- Add kthread_create() failure handling and bail out.
- Hold usbip_device lock to update local and shared states after
creating rx and tx threads.
- Update usbip_device status to SDEV_ST_USED.
- Update usbip_device tcp_socket, sockfd, tcp_rx, and tcp_tx
- Start threads after usbip_device (tcp_socket, sockfd, tcp_rx, tcp_tx,
and status) is complete.
Credit goes to syzbot and Tetsuo Handa for finding and root-causing the
kthread_get_run() improper error handling problem and others. This is a
hard problem to find and debug since the races aren't seen in a normal
case. Fuzzing forces the race window to be small enough for the
kthread_get_run() error path bug and starting threads before updating the
local and shared state bug in the stub-up sequence.
Tested with syzbot reproducer:
- https://syzkaller.appspot.com/text?tag=ReproC&x=14801034d00000
Fixes: 9720b4bc76a83807 ("staging/usbip: convert to kthread")
Cc: stable@vger.kernel.org
Reported-by: syzbot <syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+bf1a360e305ee719e364@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/268a0668144d5ff36ec7d87fdfa90faf583b7ccc.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 47ccc8fc2c9c94558b27b6f9e2582df32d29e6e8 upstream.
Fix usbip_sockfd_store() to validate the passed in file descriptor is
a stream socket. If the file descriptor passed was a SOCK_DGRAM socket,
sock_recvmsg() can't detect end of stream.
Cc: stable@vger.kernel.org
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/e942d2bd03afb8e8552bd2a5d84e18d17670d521.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 22076557b07c12086eeb16b8ce2b0b735f7a27e7 upstream.
usbip_host updates device status without holding lock from stub probe,
disconnect and rebind code paths. When multiple requests to import a
device are received, these unprotected code paths step all over each
other and drive fails with NULL-ptr deref and use-after-free errors.
The driver uses a table lock to protect the busid array for adding and
deleting busids to the table. However, the probe, disconnect and rebind
paths get the busid table entry and update the status without holding
the busid table lock. Add a new finer grain lock to protect the busid
entry. This new lock will be held to search and update the busid entry
fields from get_busid_idx(), add_match_busid() and del_match_busid().
match_busid_show() does the same to access the busid entry fields.
get_busid_priv() changed to return the pointer to the busid entry holding
the busid lock. stub_probe(), stub_disconnect() and stub_device_rebind()
call put_busid_priv() to release the busid lock before returning. This
changes fixes the unprotected code paths eliminating the race conditions
in updating the busid entries.
Reported-by: Jakub Jirasek
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7510df3f29d44685bab7b1918b61a8ccd57126a9 upstream.
After removing usbip_host module, devices it releases are left without
a driver. For example, when a keyboard or a mass storage device are
bound to usbip_host when it is removed, these devices are no longer
bound to any driver.
Fix it to run device_attach() from the module exit routine to restore
the devices to their original drivers. This includes cleanup changes
and moving device_attach() code to a common routine to be called from
rebind_store() and usbip_host_exit().
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 28b68acc4a88dcf91fd1dcf2577371dc9bf574cc upstream.
Refine probe and disconnect debug msgs to be useful and say what is
in progress.
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 009f41aed4b3e11e6dc1e3c07377a10c20f1a5ed upstream.
Keep usbip_device sockfd state in sync with tcp_socket. When tcp_socket
is reset to null, reset sockfd to -1 to keep it in sync.
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 90120d15f4c397272aaf41077960a157fc4212bf upstream.
usbip driver is leaking socket pointer address in messages. Remove
the messages that aren't useful and print sockfd in the ones that
are useful for debugging.
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If usb_hub_claim_port() fails, no resources are deallocated and
if stub_add_files() fails, port is not released.
The patch fixes these issues and rearranges error handling code.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This was used back when usbip-host was an interface device driver;
after the conversion to device driver, the table remained unused.
Remove it in order to stop receiving a warning about it.
Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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At this point, USB/IP kernel code is fully functional
and can be moved out of staging.
Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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