| From foo@baz Sun 01 Mar 2020 10:24:06 AM CET |
| From: Xin Long <lucien.xin@gmail.com> |
| Date: Tue, 18 Feb 2020 12:07:53 +0800 |
| Subject: sctp: move the format error check out of __sctp_sf_do_9_1_abort |
| |
| 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 |
| @@ -170,6 +170,16 @@ 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. |
| **********************************************************/ |
| @@ -2255,6 +2265,9 @@ 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); |
| } |
| |
| @@ -2298,6 +2311,9 @@ 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)); |
| @@ -2565,6 +2581,9 @@ 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); |
| } |
| |
| @@ -2582,16 +2601,8 @@ 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. */ |