From: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== [ Upstream commit bf911e985d6bbaa328c20c3e05f4eb03de11fdd6 ] Andrey Konovalov reported that KASAN detected that SCTP was using a slab beyond the boundaries. It was caused because when handling out of the blue packets in function sctp_sf_ootb() it was checking the chunk len only after already processing the first chunk, validating only for the 2nd and subsequent ones. The fix is to just move the check upwards so it's also validated for the 1st chunk. Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> Reviewed-by: Xin Long <lucien.xin@xxxxxxxxx> Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- net/sctp/sm_statefuns.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 63a116c31a8b..ce6c8910f041 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -3427,6 +3427,12 @@ sctp_disposition_t sctp_sf_ootb(struct net *net, return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); + /* Report violation if chunk len overflows */ + ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); + if (ch_end > skb_tail_pointer(skb)) + return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, + commands); + /* Now that we know we at least have a chunk header, * do things that are type appropriate. */ @@ -3458,12 +3464,6 @@ sctp_disposition_t sctp_sf_ootb(struct net *net, } } - /* Report violation if chunk len overflows */ - ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); - if (ch_end > skb_tail_pointer(skb)) - return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, - commands); - ch = (sctp_chunkhdr_t *) ch_end; } while (ch_end < skb_tail_pointer(skb)); -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html