From: Florian Westphal <fw@xxxxxxxxx>
Maze reports "tcp option fastopen exists" fails to match on
OpenWrt 22.03.5, r20134-5f15225c1e (5.10.176) router.
"tcp option fastopen exists" translates to:
inet
[ exthdr load tcpopt 1b @ 34 + 0 present => reg 1 ]
[ cmp eq reg 1 0x00000001 ]
.. but existing nft userspace generates a 1-byte compare.
On LSB (x86), "*reg32 = 1" is identical to nft_reg_store8(reg32, 1), but
not on MSB, which will place the 1 last. IOW, on bigendian aches the cmp8
is awalys false.
Make sure we store this in a consistent fashion, so existing userspace
will also work on MSB (bigendian).
Regardless of this patch we can also change nft userspace to generate
'reg32 == 0' and 'reg32 != 0' instead of u8 == 0 // u8 == 1 when
adding 'option x missing/exists' expressions as well.
Fixes: 3c1fece8819e ("netfilter: nft_exthdr: Allow checking TCP option presence, too")
Fixes: b9f9a485fb0e ("netfilter: nft_exthdr: add boolean DCCP option matching")
Fixes: 055c4b34b94f ("netfilter: nft_fib: Support existence check")
Reported-by: Maciej Żenczykowski <zenczykowski@xxxxxxxxx>
Closes: https://lore.kernel.org/netfilter-devel/CAHo-OozyEqHUjL2-ntATzeZOiuftLWZ_HU6TOM_js4qLfDEAJg@xxxxxxxxxxxxxx/
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Acked-by: Phil Sutter <phil@xxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nft_exthdr.c | 4 ++--
net/netfilter/nft_fib.c | 8 ++++++--
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 3fbaa7bf41f9..6eb571d0c3fd 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -214,7 +214,7 @@ static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
offset = i + priv->offset;
if (priv->flags & NFT_EXTHDR_F_PRESENT) {
- *dest = 1;
+ nft_reg_store8(dest, 1);
} else {
if (priv->len % NFT_REG32_SIZE)
dest[priv->len / NFT_REG32_SIZE] = 0;
@@ -461,7 +461,7 @@ static void nft_exthdr_dccp_eval(const struct nft_expr *expr,
type = bufp[0];
if (type == priv->type) {
- *dest = 1;
+ nft_reg_store8(dest, 1);
return;
}
diff --git a/net/netfilter/nft_fib.c b/net/netfilter/nft_fib.c
index 1bfe258018da..37cfe6dd712d 100644
--- a/net/netfilter/nft_fib.c
+++ b/net/netfilter/nft_fib.c
@@ -145,11 +145,15 @@ void nft_fib_store_result(void *reg, const struct nft_fib *priv,
switch (priv->result) {
case NFT_FIB_RESULT_OIF:
index = dev ? dev->ifindex : 0;
- *dreg = (priv->flags & NFTA_FIB_F_PRESENT) ? !!index : index;
+ if (priv->flags & NFTA_FIB_F_PRESENT)
+ nft_reg_store8(dreg, !!index);
+ else
+ *dreg = index;
+
break;
case NFT_FIB_RESULT_OIFNAME:
if (priv->flags & NFTA_FIB_F_PRESENT)
- *dreg = !!dev;
+ nft_reg_store8(dreg, !!dev);
else
strscpy_pad(reg, dev ? dev->name : "", IFNAMSIZ);
break;
--
2.30.2
