Commit 186d51d4 authored Sep 04, 2019 by Niklas Cassel Committed by Greg Kroah-Hartman Jan 17, 2020

PCI: dwc: Fix find_next_bit() usage



commit 1137e61dcb99f7f8b54e77ed83f68b5b485a3e34 upstream.

find_next_bit() takes a parameter of size long, and performs arithmetic
that assumes that the argument is of size long.

Therefore we cannot pass a u32, since this will cause find_next_bit()
to read outside the stack buffer and will produce the following print:
BUG: KASAN: stack-out-of-bounds in find_next_bit+0x38/0xb0

Fixes: 1b497e64 ("PCI: dwc: Fix uninitialized variable in dw_handle_msi_irq()")
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 731afe8a

drivers/pci/controller/dwc/pcie-designware-host.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -78,7 +78,8 @@ static struct msi_domain_info dw_pcie_msi_domain_info = {
		irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
		{
		int i, pos, irq;
		u32 val, num_ctrls;
		unsigned long val;
		u32 status, num_ctrls;
		irqreturn_t ret = IRQ_NONE;

		num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
		@@ -86,14 +87,14 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
		for (i = 0; i < num_ctrls; i++) {
		dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS +
		(i * MSI_REG_CTRL_BLOCK_SIZE),
		4, &val);
		if (!val)
		4, &status);
		if (!status)
		continue;

		ret = IRQ_HANDLED;
		val = status;
		pos = 0;
		while ((pos = find_next_bit((unsigned long *) &val,
		MAX_MSI_IRQS_PER_CTRL,
		while ((pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL,
		pos)) != MAX_MSI_IRQS_PER_CTRL) {
		irq = irq_find_mapping(pp->irq_domain,
		(i * MAX_MSI_IRQS_PER_CTRL) +