6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Florian Westphal fw@strlen.de
[ Upstream commit 63331e37fb227e796894b31d713697612c8dee7f ]
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@gmail.com Closes: https://lore.kernel.org/netfilter-devel/CAHo-OozyEqHUjL2-ntATzeZOiuftLWZ_HU6... Signed-off-by: Florian Westphal fw@strlen.de Acked-by: Phil Sutter phil@nwl.cc Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 3fbaa7bf41f9c..6eb571d0c3fdf 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 04b51f2853321..ca905aa8227e5 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;