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From:   Grant Grundler <grundler@chromium.org>
To:     Igor Russkikh <irusskikh@marvell.com>
Cc:     Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
        netdev <netdev@vger.kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        LKML <linux-kernel@vger.kernel.org>,
        Aashay Shringarpure <aashay@google.com>,
        Yi Chou <yich@google.com>,
        Shervin Oloumi <enlightened@google.com>,
        Grant Grundler <grundler@chromium.org>
Subject: [PATCH 5/5] net: atlantic: verify hw_head_ is reasonable
Date:   Mon, 18 Apr 2022 16:17:46 -0700
Message-Id: <20220418231746.2464800-6-grundler@chromium.org>
In-Reply-To: <20220418231746.2464800-1-grundler@chromium.org>
References: <20220418231746.2464800-1-grundler@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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Bounds check hw_head index to verify it lies within the TX buffer ring.

Unexpected values of hw_head may cause aq_ring_tx_clean to double
dev_kfree_skb_any already cleaned parts of the ring.

Reported-by: Aashay Shringarpure <aashay@google.com>
Reported-by: Yi Chou <yich@google.com>
Reported-by: Shervin Oloumi <enlightened@google.com>
Signed-off-by: Grant Grundler <grundler@chromium.org>
---
 .../aquantia/atlantic/hw_atl/hw_atl_b0.c      | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
index e72b9d86f6ad..9b6b93bb3e86 100644
--- a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
+++ b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
@@ -889,6 +889,27 @@ int hw_atl_b0_hw_ring_tx_head_update(struct aq_hw_s *self,
 		err = -ENXIO;
 		goto err_exit;
 	}
+
+	/* Validate that the new hw_head_ is reasonable. */
+	if (hw_head_ >= ring->size) {
+		err = -ENXIO;
+		goto err_exit;
+	}
+
+	if (ring->sw_head >= ring->sw_tail) {
+		/* Head index hasn't wrapped around to below tail index. */
+		if (hw_head_ < ring->sw_head && hw_head_ >= ring->sw_tail) {
+			err = -ENXIO;
+			goto err_exit;
+		}
+	} else {
+		/* Head index has wrapped around and is below tail index. */
+		if (hw_head_ < ring->sw_head || hw_head_ >= ring->sw_tail) {
+			err = -ENXIO;
+			goto err_exit;
+		}
+	}
+
 	ring->hw_head = hw_head_;
 	err = aq_hw_err_from_flags(self);
 
-- 
2.36.0.rc0.470.gd361397f0d-goog