From: Xin Long lucien.xin@gmail.com
[ Upstream commit 245709ec8be89af46ea7ef0444c9c80913999d99 ]
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.
v1->v2: - improve the comment in the code as Marcelo's suggestion.
Fixes: 96ca468b86b0 ("sctp: check invalid value of length parameter in error cause") Reported-by: Hangbin Liu liuhangbin@gmail.com Acked-by: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sctp/sm_statefuns.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-)
--- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -185,6 +185,16 @@ static inline bool sctp_chunk_length_val return true; }
+/* Check for 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. **********************************************************/ @@ -2270,6 +2280,9 @@ enum sctp_disposition sctp_sf_shutdown_p 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); }
@@ -2313,6 +2326,9 @@ enum sctp_disposition sctp_sf_shutdown_s 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)); @@ -2580,6 +2596,9 @@ enum sctp_disposition sctp_sf_do_9_1_abo 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); }
@@ -2597,16 +2616,8 @@ static enum sctp_disposition __sctp_sf_d
/* 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. */