diff options
| author |   Shuah Khan (Samsung OSG) <shuah@kernel.org> | 2018-05-15 17:57:23 -0600 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-16 18:52:13 +0200 |
| commit | c171654caa875919be3c533d3518da8be5be966e (patch) | |
| tree | 8653b88f370ff454886bd93ae00ba6a68a3b647b /drivers | |
| parent | usbip: usbip_host: fix NULL-ptr deref and use-after-free errors (diff) | |
| download | linux-dev-c171654caa875919be3c533d3518da8be5be966e.tar.xz linux-dev-c171654caa875919be3c533d3518da8be5be966e.zip | |
usbip: usbip_host: fix bad unlock balance during stub_probe()
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@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/usbip/stub_main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c index 41c7b9de2a92..bf8a5feb0ee9 100644 --- a/drivers/usb/usbip/stub_main.c +++ b/drivers/usb/usbip/stub_main.c @@ -82,7 +82,8 @@ struct bus_id_priv *get_busid_priv(const char *busid) 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) |