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authorShuah Khan (Samsung OSG) <shuah@kernel.org>2018-05-15 17:57:23 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-16 18:52:13 +0200
commitc171654caa875919be3c533d3518da8be5be966e (patch)
tree8653b88f370ff454886bd93ae00ba6a68a3b647b /drivers/usb/usbip/stub_main.c
parent22076557b07c12086eeb16b8ce2b0b735f7a27e7 (diff)
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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/usb/usbip/stub_main.c')
-rw-r--r--drivers/usb/usbip/stub_main.c3
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)