From: Anssi Hannula anssi.hannula@bitwise.fi
commit 05519b8589a679edb8fa781259893d20bece04ad upstream.
xhci_decode_ctrl_ctx() returns the untouched buffer as-is if both "drop" and "add" parameters are zero.
Fix the function to return an empty string in that case.
It was not immediately clear from the possible call chains whether this issue is currently actually triggerable or not.
Note that before commit 4843b4b5ec64 ("xhci: fix even more unsafe memory usage in xhci tracing") the result effect in the failure case was different as a static buffer was used here, but the code still worked incorrectly.
Fixes: 90d6d5731da7 ("xhci: Add tracing for input control context") Cc: stable@vger.kernel.org Signed-off-by: Anssi Hannula anssi.hannula@bitwise.fi Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com commit 4843b4b5ec64 ("xhci: fix even more unsafe memory usage in xhci tracing") Link: https://lore.kernel.org/r/20220303110903.1662404-4-mathias.nyman@linux.intel... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/host/xhci.h | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -2452,6 +2452,8 @@ static inline const char *xhci_decode_ct unsigned int bit; int ret = 0;
+ str[0] = '\0'; + if (drop) { ret = sprintf(str, "Drop:"); for_each_set_bit(bit, &drop, 32)