net: convert sk_buff.users from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 20299df163b9..e8762702a313 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -1102,7 +1102,7 @@ static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp)
                                  sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
                                  "illegal chunk", ntohl(chunk->subh.data_hdr->tsn),
                                  chunk->skb ? chunk->skb->head : NULL, chunk->skb ?
-                                 atomic_read(&chunk->skb->users) : -1);
+                                 refcount_read(&chunk->skb->users) : -1);
 
                         /* Add the chunk to the packet.  */
                         status = sctp_packet_transmit_chunk(packet, chunk, 0, gfp);