From 0a0c61dd071d7affdbfcf0d87dc5cb10b1d0980c Mon Sep 17 00:00:00 2001 From: Anssi Hannula Date: Thu, 3 Mar 2022 13:08:57 +0200 Subject: [PATCH] xhci: fix uninitialized string returned by xhci_decode_ctrl_ctx() 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 Signed-off-by: Mathias Nyman 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.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 8fd838f9d56a..a46bbf5beffa 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -2458,6 +2458,8 @@ static inline const char *xhci_decode_ctrl_ctx(char *str, unsigned int bit; int ret = 0; + str[0] = '\0'; + if (drop) { ret = sprintf(str, "Drop:"); for_each_set_bit(bit, &drop, 32)