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sctp: fix the issue that a __u16 variable may overflow in sctp_ulpq_renege 

[ Upstream commit 5c468674d1 ]

Now when reneging events in sctp_ulpq_renege(), the variable freed
could be increased by a __u16 value twice while freed is of __u16
type. It means freed may overflow at the second addition.

This patch is to fix it by using __u32 type for 'freed', while at
it, also to remove 'if (chunk)' check, as all renege commands are
generated in sctp_eat_data and it can't be NULL.

Reported-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Xin Long 2017-12-18 14:07:25 +08:00 committed by Greg Kroah-Hartman
parent c8b8dd7359
commit 60f1c1f279
1 changed files with 8 additions and 16 deletions
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24
net/sctp/ulpqueue.c
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@ -1084,29 +1084,21 @@ void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
gfp_t gfp)
{
struct sctp_association *asoc;
__u16 needed, freed;
struct sctp_association *asoc = ulpq->asoc;
__u32 freed = 0;
__u16 needed;
asoc = ulpq->asoc;
if (chunk) {
needed = ntohs(chunk->chunk_hdr->length);
needed -= sizeof(struct sctp_data_chunk);
} else
needed = SCTP_DEFAULT_MAXWINDOW;
freed = 0;
needed = ntohs(chunk->chunk_hdr->length) -
sizeof(struct sctp_data_chunk);
if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
freed = sctp_ulpq_renege_order(ulpq, needed);
if (freed < needed) {
if (freed < needed)
freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
}
}
/* If able to free enough room, accept this chunk. */
if (chunk && (freed >= needed)) {
int retval;
retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
if (freed >= needed) {
int retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
/*
* Enter partial delivery if chunk has not been
* delivered; otherwise, drain the reassembly queue.