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authorMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>2016-10-25 14:27:39 -0200
committerDavid S. Miller <davem@davemloft.net>2016-10-29 12:00:10 -0400
commitbf911e985d6bbaa328c20c3e05f4eb03de11fdd6 (patch)
tree1b27244b2383e75616e7c1d4a3c1faa329108f99 /net
parentc2e169be8ce7bde1e4189dc6e72eb9861fe9b6fb (diff)
downloadlinux-bf911e985d6bbaa328c20c3e05f4eb03de11fdd6.tar.bz2
sctp: validate chunk len before actually using it
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@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/sm_statefuns.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 026e3bca4a94..8ec20a64a3f8 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -3422,6 +3422,12 @@ 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) + SCTP_PAD4(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.
*/
@@ -3453,12 +3459,6 @@ sctp_disposition_t sctp_sf_ootb(struct net *net,
}
}
- /* Report violation if chunk len overflows */
- ch_end = ((__u8 *)ch) + SCTP_PAD4(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));