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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jeremy Sowden <jeremy@azazel.net>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.17 196/343] netfilter: bitwise: fix reduce comparisons
Date:   Tue, 12 Apr 2022 08:30:14 +0200
Message-Id: <20220412062957.013993867@linuxfoundation.org>
In-Reply-To: <20220412062951.095765152@linuxfoundation.org>
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From: Jeremy Sowden <jeremy@azazel.net>

[ Upstream commit 31818213170caa51d116eb5dc1167b88523b4fe1 ]

The `nft_bitwise_reduce` and `nft_bitwise_fast_reduce` functions should
compare the bitwise operation in `expr` with the tracked operation
associated with the destination register of `expr`.  However, instead of
being called on `expr` and `track->regs[priv->dreg].selector`,
`nft_expr_priv` is called on `expr` twice, so both reduce functions
return true even when the operations differ.

Fixes: be5650f8f47e ("netfilter: nft_bitwise: track register operations")
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nft_bitwise.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nft_bitwise.c b/net/netfilter/nft_bitwise.c
index 7b727d3ebf9d..04bd2f89afe8 100644
--- a/net/netfilter/nft_bitwise.c
+++ b/net/netfilter/nft_bitwise.c
@@ -287,7 +287,7 @@ static bool nft_bitwise_reduce(struct nft_regs_track *track,
 	if (!track->regs[priv->sreg].selector)
 		return false;
 
-	bitwise = nft_expr_priv(expr);
+	bitwise = nft_expr_priv(track->regs[priv->dreg].selector);
 	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
 	    track->regs[priv->dreg].bitwise &&
 	    track->regs[priv->dreg].bitwise->ops == expr->ops &&
@@ -434,7 +434,7 @@ static bool nft_bitwise_fast_reduce(struct nft_regs_track *track,
 	if (!track->regs[priv->sreg].selector)
 		return false;
 
-	bitwise = nft_expr_priv(expr);
+	bitwise = nft_expr_priv(track->regs[priv->dreg].selector);
 	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
 	    track->regs[priv->dreg].bitwise &&
 	    track->regs[priv->dreg].bitwise->ops == expr->ops &&
-- 
2.35.1