netfilter: nf_tables: Add size check on u8 nft_exthdr attributes
diff mbox

Message ID 20160809184614.GA8947@sonyv
State Accepted
Delegated to: Pablo Neira
Headers show

Commit Message

Laura Garcia Liebana Aug. 9, 2016, 6:46 p.m. UTC
Fix the direct assignment of offset and length attributes included in
nft_exthdr structure from u32 data to u8.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
---
 net/netfilter/nft_exthdr.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

Comments

Pablo Neira Ayuso Aug. 10, 2016, 10:57 a.m. UTC | #1
On Tue, Aug 09, 2016 at 08:46:16PM +0200, Laura Garcia Liebana wrote:
> Fix the direct assignment of offset and length attributes included in
> nft_exthdr structure from u32 data to u8.

Applied to my nf tree, I just made a minor edition on this patch.

Thanks.
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Pablo Neira Ayuso Aug. 10, 2016, 10:58 a.m. UTC | #2
On Wed, Aug 10, 2016 at 12:57:45PM +0200, Pablo Neira Ayuso wrote:
> On Tue, Aug 09, 2016 at 08:46:16PM +0200, Laura Garcia Liebana wrote:
> > Fix the direct assignment of offset and length attributes included in
> > nft_exthdr structure from u32 data to u8.
> 
> Applied to my nf tree, I just made a minor edition on this patch.

It would be good to search for similar issues in other existing
expressions, BTW. Let me know if you can take care of it. Thanks.
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Laura Garcia Liebana Aug. 10, 2016, 11 a.m. UTC | #3
On Wed, Aug 10, 2016 at 12:58:38PM +0200, Pablo Neira Ayuso wrote:
> On Wed, Aug 10, 2016 at 12:57:45PM +0200, Pablo Neira Ayuso wrote:
> > On Tue, Aug 09, 2016 at 08:46:16PM +0200, Laura Garcia Liebana wrote:
> > > Fix the direct assignment of offset and length attributes included in
> > > nft_exthdr structure from u32 data to u8.
> > 
> > Applied to my nf tree, I just made a minor edition on this patch.
> 
> It would be good to search for similar issues in other existing
> expressions, BTW. Let me know if you can take care of it. Thanks.

Sure, count on it.

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Patch
diff mbox

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index ba7aed1..dec3c36 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -59,6 +59,7 @@  static int nft_exthdr_init(const struct nft_ctx *ctx,
 			   const struct nlattr * const tb[])
 {
 	struct nft_exthdr *priv = nft_expr_priv(expr);
+	u32 offset, len;
 
 	if (tb[NFTA_EXTHDR_DREG] == NULL ||
 	    tb[NFTA_EXTHDR_TYPE] == NULL ||
@@ -67,8 +68,16 @@  static int nft_exthdr_init(const struct nft_ctx *ctx,
 		return -EINVAL;
 
 	priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
-	priv->offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
-	priv->len    = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
+
+	offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
+	len    = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
+
+	if (offset > U8_MAX || len > U8_MAX)
+		return -EINVAL;
+
+	priv->offset = offset;
+	priv->len = len;
+
 	priv->dreg   = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
 
 	return nft_validate_register_store(ctx, priv->dreg, NULL,