DivestOS/Patches/Linux_CVEs/CVE-2016-9555/ANY/0.patch
2017-10-29 22:14:37 -04:00

55 lines
2.1 KiB
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From bf911e985d6bbaa328c20c3e05f4eb03de11fdd6 Mon Sep 17 00:00:00 2001
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Tue, 25 Oct 2016 14:27:39 -0200
Subject: [PATCH] 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>
---
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 026e3bca4a94b..8ec20a64a3f80 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));