[nf-next PATCH] netfilter: nft_exthdr: Fix for unsafe packet data read

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



While iterating through an SCTP packet's chunks, skb_header_pointer() is
called for the minimum expected chunk header size. If (that part of) the
skbuff is non-linear, the following memcpy() may read data past
temporary buffer '_sch'. Use skb_copy_bits() instead which does the
right thing in this situation.

Fixes: 133dc203d77df ("netfilter: nft_exthdr: Support SCTP chunks")
Suggested-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
 net/netfilter/nft_exthdr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 1b0579cb62d08..2b976687510d8 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -327,7 +327,8 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
 				break;
 
 			dest[priv->len / NFT_REG32_SIZE] = 0;
-			memcpy(dest, (char *)sch + priv->offset, priv->len);
+			skb_copy_bits(pkt->skb, offset + priv->offset,
+				      dest, priv->len);
 			return;
 		}
 		offset += SCTP_PAD4(ntohs(sch->length));
-- 
2.31.1




[Index of Archives]     [Netfitler Users]     [Berkeley Packet Filter]     [LARTC]     [Bugtraq]     [Yosemite Forum]

  Powered by Linux