| From c171654caa875919be3c533d3518da8be5be966e Mon Sep 17 00:00:00 2001 |
| From: "Shuah Khan (Samsung OSG)" <shuah@kernel.org> |
| Date: Tue, 15 May 2018 17:57:23 -0600 |
| Subject: usbip: usbip_host: fix bad unlock balance during stub_probe() |
| |
| From: Shuah Khan (Samsung OSG) <shuah@kernel.org> |
| |
| commit c171654caa875919be3c533d3518da8be5be966e upstream. |
| |
| stub_probe() calls put_busid_priv() in an error path when device isn't |
| found in the busid_table. Fix it by making put_busid_priv() safe to be |
| called with null struct bus_id_priv pointer. |
| |
| This problem happens when "usbip bind" is run without loading usbip_host |
| driver and then running modprobe. The first failed bind attempt unbinds |
| the device from the original driver and when usbip_host is modprobed, |
| stub_probe() runs and doesn't find the device in its busid table and calls |
| put_busid_priv(0 with null bus_id_priv pointer. |
| |
| usbip-host 3-10.2: 3-10.2 is not in match_busid table... skip! |
| |
| [ 367.359679] ===================================== |
| [ 367.359681] WARNING: bad unlock balance detected! |
| [ 367.359683] 4.17.0-rc4+ #5 Not tainted |
| [ 367.359685] ------------------------------------- |
| [ 367.359688] modprobe/2768 is trying to release lock ( |
| [ 367.359689] |
| ================================================================== |
| [ 367.359696] BUG: KASAN: null-ptr-deref in print_unlock_imbalance_bug+0x99/0x110 |
| [ 367.359699] Read of size 8 at addr 0000000000000058 by task modprobe/2768 |
| |
| [ 367.359705] CPU: 4 PID: 2768 Comm: modprobe Not tainted 4.17.0-rc4+ #5 |
| |
| Fixes: 22076557b07c ("usbip: usbip_host: fix NULL-ptr deref and use-after-free errors") in usb-linus |
| 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> |
| |
| --- |
| drivers/usb/usbip/stub_main.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/usb/usbip/stub_main.c |
| +++ b/drivers/usb/usbip/stub_main.c |
| @@ -96,7 +96,8 @@ struct bus_id_priv *get_busid_priv(const |
| |
| void put_busid_priv(struct bus_id_priv *bid) |
| { |
| - spin_unlock(&bid->busid_lock); |
| + if (bid) |
| + spin_unlock(&bid->busid_lock); |
| } |
| |
| static int add_match_busid(char *busid) |