[Patch v8 6/8] PCI: tegra194: Fix possible array out of bounds access

Sumit Gupta
2023-05-11T17:34:57Z

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>
---
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 09825b4a075e..e6eec85480ca 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);

--
2.17.1