irda: precedence bug in irlmp_seq_hb_idx()

[ Upstream commit 50010c20597d14667eff0fdb628309986f195230 ]

This is decrementing the pointer, instead of the value stored in the
pointer.  KASan detects it as an out of bounds reference.

Reported-by: "Berry Cheng 程君(成淼)" <chengmiao.cj@alibaba-inc.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/irda/irlmp.c b/net/irda/irlmp.c
index 6115a44..0721f82 100644 (file)
--- a/net/irda/irlmp.c
+++ b/net/irda/irlmp.c
@@ -1868,7 +1868,7 @@ static void *irlmp_seq_hb_idx(struct irlmp_iter_state *iter, loff_t *off)
        for (element = hashbin_get_first(iter->hashbin);
             element != NULL;
             element = hashbin_get_next(iter->hashbin)) {
-               if (!off || *off-- == 0) {
+               if (!off || (*off)-- == 0) {
                        /* NB: hashbin left locked */
                        return element;
                }