Messages in this thread Patch in this message | | | From | Akinobu Mita <> | Subject | [PATCH] wusb: fix find_first_zero_bit() return value check | Date | Wed, 2 Mar 2011 20:35:28 +0900 |
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In wusb_cluster_id_get(), if no zero bits exist in wusb_cluster_id_table, find_first_zero_bit() returns CLUSTER_IDS.
But it is impossible to detect that the bitmap is full because there is an off-by-one error in the return value check. It will cause unexpected memory access by setting bit out of wusb_cluster_id_table bitmap, and caller will get wrong cluster id.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: linux-usb@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@suse.de> --- drivers/usb/wusbcore/wusbhc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/wusbcore/wusbhc.c b/drivers/usb/wusbcore/wusbhc.c index 2054d4e..0faca16 100644 --- a/drivers/usb/wusbcore/wusbhc.c +++ b/drivers/usb/wusbcore/wusbhc.c @@ -320,7 +320,7 @@ u8 wusb_cluster_id_get(void) u8 id; spin_lock(&wusb_cluster_ids_lock); id = find_first_zero_bit(wusb_cluster_id_table, CLUSTER_IDS); - if (id > CLUSTER_IDS) { + if (id >= CLUSTER_IDS) { id = 0; goto out; } -- 1.7.4
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