From: Marcelo Ricardo Leitner Date: Fri, 8 Jan 2016 13:00:54 +0000 (-0200) Subject: sctp: fix use-after-free in pr_debug statement X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=649621e3d54439ae232d726d7beef295d3887a68;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git sctp: fix use-after-free in pr_debug statement Dmitry Vyukov reported a use-after-free in the code expanded by the macro debug_post_sfx, which is caused by the use of the asoc pointer after it was freed within sctp_side_effect() scope. This patch fixes it by allowing sctp_side_effect to clear that asoc pointer when the TCB is freed. As Vlad explained, we also have to cover the SCTP_DISPOSITION_ABORT case because it will trigger DELETE_TCB too on that same loop. Also, there were places issuing SCTP_CMD_INIT_FAILED and ASSOC_FAILED but returning SCTP_DISPOSITION_CONSUME, which would fool the scheme above. Fix it by returning SCTP_DISPOSITION_ABORT instead. The macro is already prepared to handle such NULL pointer. Reported-by: Dmitry Vyukov Signed-off-by: Marcelo Ricardo Leitner Acked-by: Vlad Yasevich Signed-off-by: David S. Miller --- diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c index 6098d4c42fa9..be23d5c2074f 100644 --- a/net/sctp/sm_sideeffect.c +++ b/net/sctp/sm_sideeffect.c @@ -63,7 +63,7 @@ static int sctp_cmd_interpreter(sctp_event_t event_type, static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype, sctp_state_t state, struct sctp_endpoint *ep, - struct sctp_association *asoc, + struct sctp_association **asoc, void *event_arg, sctp_disposition_t status, sctp_cmd_seq_t *commands, @@ -1123,7 +1123,7 @@ int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype, debug_post_sfn(); error = sctp_side_effects(event_type, subtype, state, - ep, asoc, event_arg, status, + ep, &asoc, event_arg, status, &commands, gfp); debug_post_sfx(); @@ -1136,7 +1136,7 @@ int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype, static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype, sctp_state_t state, struct sctp_endpoint *ep, - struct sctp_association *asoc, + struct sctp_association **asoc, void *event_arg, sctp_disposition_t status, sctp_cmd_seq_t *commands, @@ -1151,7 +1151,7 @@ static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype, * disposition SCTP_DISPOSITION_CONSUME. */ if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state, - ep, asoc, + ep, *asoc, event_arg, status, commands, gfp))) goto bail; @@ -1174,11 +1174,12 @@ static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype, break; case SCTP_DISPOSITION_DELETE_TCB: + case SCTP_DISPOSITION_ABORT: /* This should now be a command. */ + *asoc = NULL; break; case SCTP_DISPOSITION_CONSUME: - case SCTP_DISPOSITION_ABORT: /* * We should no longer have much work to do here as the * real work has been done as explicit commands above. diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 22c2bf367d7e..f1f08c8f277b 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -2976,7 +2976,7 @@ sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); goto discard_force; case SCTP_IERROR_NO_DATA: - goto consume; + return SCTP_DISPOSITION_ABORT; case SCTP_IERROR_PROTO_VIOLATION: return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); @@ -3043,9 +3043,6 @@ discard_noforce: sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); return SCTP_DISPOSITION_DISCARD; -consume: - return SCTP_DISPOSITION_CONSUME; - } /* @@ -3093,7 +3090,7 @@ sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, case SCTP_IERROR_BAD_STREAM: break; case SCTP_IERROR_NO_DATA: - goto consume; + return SCTP_DISPOSITION_ABORT; case SCTP_IERROR_PROTO_VIOLATION: return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); @@ -3119,7 +3116,6 @@ sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); } -consume: return SCTP_DISPOSITION_CONSUME; } @@ -4825,9 +4821,6 @@ sctp_disposition_t sctp_sf_do_9_1_prm_abort( * if necessary to fill gaps. */ struct sctp_chunk *abort = arg; - sctp_disposition_t retval; - - retval = SCTP_DISPOSITION_CONSUME; if (abort) sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); @@ -4845,7 +4838,7 @@ sctp_disposition_t sctp_sf_do_9_1_prm_abort( SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); - return retval; + return SCTP_DISPOSITION_ABORT; } /* We tried an illegal operation on an association which is closed. */ @@ -4960,12 +4953,10 @@ sctp_disposition_t sctp_sf_cookie_wait_prm_abort( sctp_cmd_seq_t *commands) { struct sctp_chunk *abort = arg; - sctp_disposition_t retval; /* Stop T1-init timer */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); - retval = SCTP_DISPOSITION_CONSUME; if (abort) sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); @@ -4985,7 +4976,7 @@ sctp_disposition_t sctp_sf_cookie_wait_prm_abort( sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, SCTP_PERR(SCTP_ERROR_USER_ABORT)); - return retval; + return SCTP_DISPOSITION_ABORT; } /*