A recent change claimed to fix an off-by-one error in the OOB-port
completion handler, but instead introduced such an error. This could
specifically led to modem-status changes going unnoticed, effectively
breaking TIOCMGET.

Note that the offending commit fixes a loop-condition underflow and is
marked for stable, but should not be backported without this fix.

Reported-by: Ben Hutchings <b...@decadent.org.uk>
Fixes: 2d380889215f ("USB: serial: digi_acceleport: fix OOB data sanity
check")
Cc: stable <sta...@vger.kernel.org>     # v2.6.30
Signed-off-by: Johan Hovold <jo...@kernel.org>
---
 drivers/usb/serial/digi_acceleport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/serial/digi_acceleport.c 
b/drivers/usb/serial/digi_acceleport.c
index eb433922598c..7ab3235febfc 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -1499,7 +1499,7 @@ static int digi_read_oob_callback(struct urb *urb)
                return -1;
 
        /* handle each oob command */
-       for (i = 0; i < urb->actual_length - 4; i += 4) {
+       for (i = 0; i < urb->actual_length - 3; i += 4) {
                opcode = buf[i];
                line = buf[i + 1];
                status = buf[i + 2];
-- 
2.11.1

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