diff options
| author | Phil Sutter | 2021-06-08 11:40:57 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso | 2021-06-09 02:42:52 +0200 |
| commit | cf6b5ffdce5a78b2fcb0e53b3a2487c490bcbf7f (patch) | |
| tree | bf2d722476e0f24697c80ca97d77172fe4caea26 | |
| parent | e2cf17d3774c323ef6dab6e9f7c0cfc5e742afd9 (diff) | |
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>
| -rw-r--r-- | net/netfilter/nft_exthdr.c | 4 |
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)); |