When T2 timer is to be stopped, the asoc should also be deleted,
otherwise, there will be no chance to call sctp_association_free
and the asoc could last in memory forever.
However, in sctp_sf_shutdown_sent_abort(), after adding the cmd
SCTP_CMD_TIMER_STOP for T2 timer, it may return error due to the
format error from __sctp_sf_do_9_1_abort() and miss adding
SCTP_CMD_ASSOC_FAILED where the asoc will be deleted.
This patch is to fix it by moving the format error check out of
__sctp_sf_do_9_1_abort(), and do it before adding the cmd
SCTP_CMD_TIMER_STOP for T2 timer.
Thanks Hangbin for reporting this issue by the fuzz testing.
Fixes: 96ca468b86b0 ("sctp: check invalid value of length parameter in error cause")
Reported-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
---
net/sctp/sm_statefuns.c | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 748e3b1..e2b2b41 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -170,6 +170,16 @@ static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
return true;
}
+/* Check for the format error in an ABORT chunk */
+static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
+{
+ struct sctp_errhdr *err;
+
+ sctp_walk_errors(err, chunk->chunk_hdr);
+
+ return (void *)err == (void *)chunk->chunk_end;
+}
+
/**********************************************************
* These are the state functions for handling chunk events.
**********************************************************/
@@ -2255,6 +2265,9 @@ enum sctp_disposition sctp_sf_shutdown_pending_abort(
sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
+ if (!sctp_err_chunk_valid(chunk))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
}
@@ -2298,6 +2311,9 @@ enum sctp_disposition sctp_sf_shutdown_sent_abort(
sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
+ if (!sctp_err_chunk_valid(chunk))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
/* Stop the T2-shutdown timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
@@ -2565,6 +2581,9 @@ enum sctp_disposition sctp_sf_do_9_1_abort(
sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
+ if (!sctp_err_chunk_valid(chunk))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
}
@@ -2582,16 +2601,8 @@ static enum sctp_disposition __sctp_sf_do_9_1_abort(
/* See if we have an error cause code in the chunk. */
len = ntohs(chunk->chunk_hdr->length);
- if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
- struct sctp_errhdr *err;
-
- sctp_walk_errors(err, chunk->chunk_hdr);
- if ((void *)err != (void *)chunk->chunk_end)
- return sctp_sf_pdiscard(net, ep, asoc, type, arg,
- commands);
-
+ if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
- }
sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
/* ASSOC_FAILED will DELETE_TCB. */
--
2.1.0
