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authorPhil Sutter <phil@nwl.cc>2021-06-08 11:40:57 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2021-06-09 02:42:52 +0200
commitcf6b5ffdce5a78b2fcb0e53b3a2487c490bcbf7f (patch)
treebf2d722476e0f24697c80ca97d77172fe4caea26 /net/netfilter
parente2cf17d3774c323ef6dab6e9f7c0cfc5e742afd9 (diff)
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netfilter: nft_exthdr: Fix for unsafe packet data read
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@strlen.de> Signed-off-by: Phil Sutter <phil@nwl.cc> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/nft_exthdr.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 1b0579cb62d0..7f705b5c09de 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -327,7 +327,9 @@ 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);
+ if (skb_copy_bits(pkt->skb, offset + priv->offset,
+ dest, priv->len) < 0)
+ break;
return;
}
offset += SCTP_PAD4(ntohs(sch->length));