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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Sumit Gupta <sumitg@nvidia.com>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Thierry Reding <treding@nvidia.com>,
        Sasha Levin <sashal@kernel.org>, kw@linux.com,
        bhelgaas@google.com, thierry.reding@gmail.com,
        jonathanh@nvidia.com, mani@kernel.org,
        Sergey.Semin@baikalelectronics.ru, robh@kernel.org,
        dmitry.baryshkov@linaro.org, linux-pci@vger.kernel.org,
        linux-tegra@vger.kernel.org
Subject: [PATCH AUTOSEL 6.4 12/58] PCI: tegra194: Fix possible array out of bounds access
Date:   Sun, 23 Jul 2023 21:12:40 -0400
Message-Id: <20230724011338.2298062-12-sashal@kernel.org>
In-Reply-To: <20230724011338.2298062-1-sashal@kernel.org>
References: <20230724011338.2298062-1-sashal@kernel.org>
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From: Sumit Gupta <sumitg@nvidia.com>

[ Upstream commit 205b3d02d57ce6dce96f6d2b9c230f56a9bf9817 ]

Add check to fix the possible array out of bounds violation by
making speed equal to GEN1_CORE_CLK_FREQ when its value is more
than the size of "pcie_gen_freq" array. This array has size of
four but possible speed (CLS) values are from "0 to 0xF". So,
"speed - 1" values are "-1 to 0xE".

Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Link: https://lore.kernel.org/lkml/72b9168b-d4d6-4312-32ea-69358df2f2d0@nvidia.com/
Acked-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 09825b4a075e5..e6eec85480ca9 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -223,6 +223,7 @@
 #define EP_STATE_ENABLED	1
 
 static const unsigned int pcie_gen_freq[] = {
+	GEN1_CORE_CLK_FREQ,	/* PCI_EXP_LNKSTA_CLS == 0; undefined */
 	GEN1_CORE_CLK_FREQ,
 	GEN2_CORE_CLK_FREQ,
 	GEN3_CORE_CLK_FREQ,
@@ -459,7 +460,11 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
 
 	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
 		PCI_EXP_LNKSTA_CLS;
-	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+
+	if (speed >= ARRAY_SIZE(pcie_gen_freq))
+		speed = 0;
+
+	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
 
 	if (pcie->of_data->has_ltr_req_fix)
 		return IRQ_HANDLED;
@@ -1020,7 +1025,11 @@ static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
 
 	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
 		PCI_EXP_LNKSTA_CLS;
-	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
+
+	if (speed >= ARRAY_SIZE(pcie_gen_freq))
+		speed = 0;
+
+	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed]);
 
 	tegra_pcie_enable_interrupts(pp);
 
-- 
2.39.2