From e7f027961759f334bcc939980ec35480faa7ef17 Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Tue, 4 Jul 2017 15:53:26 +0300 Subject: [PATCH] net, sctp: convert sctp_chunk.refcnt 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 Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 2 +- net/sctp/sm_make_chunk.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 4d7c855..0dfc5c1 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -524,7 +524,7 @@ int sctp_chunk_abandoned(struct sctp_chunk *); struct sctp_chunk { struct list_head list; - atomic_t refcnt; + refcount_t refcnt; /* How many times this chunk have been sent, for prsctp RTX policy */ int sent_count; diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c index 3af4dd0..4e16b02 100644 --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -1345,7 +1345,7 @@ struct sctp_chunk *sctp_chunkify(struct sk_buff *skb, INIT_LIST_HEAD(&retval->transmitted_list); INIT_LIST_HEAD(&retval->frag_list); SCTP_DBG_OBJCNT_INC(chunk); - atomic_set(&retval->refcnt, 1); + refcount_set(&retval->refcnt, 1); nodata: return retval; @@ -1458,13 +1458,13 @@ void sctp_chunk_free(struct sctp_chunk *chunk) /* Grab a reference to the chunk. */ void sctp_chunk_hold(struct sctp_chunk *ch) { - atomic_inc(&ch->refcnt); + refcount_inc(&ch->refcnt); } /* Release a reference to the chunk. */ void sctp_chunk_put(struct sctp_chunk *ch) { - if (atomic_dec_and_test(&ch->refcnt)) + if (refcount_dec_and_test(&ch->refcnt)) sctp_chunk_destroy(ch); } -- 2.7.4