[PATCH 5.4 262/344] ide: serverworks: potential overflow in svwks_set_pio_mode()

Greg Kroah-Hartman
2020-02-21T08:13:55Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit ce1f31b4c0b9551dd51874dd5364654ed4ca13ae ]

The "drive->dn" variable is a u8 controlled by root.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/ide/serverworks.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/ide/serverworks.c b/drivers/ide/serverworks.c
index ac6fc3fffa0de..458e72e034b09 100644
--- a/drivers/ide/serverworks.c
+++ b/drivers/ide/serverworks.c
@@ -115,6 +115,9 @@ static void svwks_set_pio_mode(ide_hwif_t *hwif, ide_drive_t *drive)
struct pci_dev *dev = to_pci_dev(hwif->dev);
const u8 pio = drive->pio_mode - XFER_PIO_0;

+ if (drive->dn >= ARRAY_SIZE(drive_pci))
+ return;
+
pci_write_config_byte(dev, drive_pci[drive->dn], pio_modes[pio]);

if (svwks_csb_check(dev)) {
@@ -141,6 +144,9 @@ static void svwks_set_dma_mode(ide_hwif_t *hwif, ide_drive_t *drive)

u8 ultra_enable = 0, ultra_timing = 0, dma_timing = 0;

+ if (drive->dn >= ARRAY_SIZE(drive_pci2))
+ return;
+
pci_read_config_byte(dev, (0x56|hwif->channel), &ultra_timing);
pci_read_config_byte(dev, 0x54, &ultra_enable);

--
2.20.1