diff mbox series

[5.17,0018/1126] xhci: fix uninitialized string returned by xhci_decode_ctrl_ctx()

Message ID 20220405070408.078203683@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman April 5, 2022, 7:12 a.m. UTC
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.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci.h |    2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -2470,6 +2470,8 @@  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)