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authorKeir Fraser <keirf@google.com>2022-03-23 14:07:27 +0000
committerMichael S. Tsirkin <mst@redhat.com>2022-03-28 16:52:59 -0400
commit3f63a1d7f6f500b6891b1003cec3e23ea4996a2e (patch)
tree2615cc453c0a7999244092a05c1dfe7f8a62c095 /drivers/virtio
parenteb4cecb453a19b34d5454b49532e09e9cb0c1529 (diff)
downloadlinux-3f63a1d7f6f500b6891b1003cec3e23ea4996a2e.tar.bz2
virtio: pci: check bar values read from virtio config space
virtio pci config structures may in future have non-standard bar values in the bar field. We should anticipate this by skipping any structures containing such a reserved value. The bar value should never change: check for harmful modified values we re-read it from the config space in vp_modern_map_capability(). Also clean up an existing check to consistently use PCI_STD_NUM_BARS. Signed-off-by: Keir Fraser <keirf@google.com> Link: https://lore.kernel.org/r/20220323140727.3499235-1-keirf@google.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio_pci_modern.c12
-rw-r--r--drivers/virtio/virtio_pci_modern_dev.c9
2 files changed, 17 insertions, 4 deletions
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 30654d3a0b41..a2671a20ef77 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -293,7 +293,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR); pos > 0;
pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
- u8 type, cap_len, id;
+ u8 type, cap_len, id, res_bar;
u32 tmp32;
u64 res_offset, res_length;
@@ -315,9 +315,14 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
if (id != required_id)
continue;
- /* Type, and ID match, looks good */
pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
- bar), bar);
+ bar), &res_bar);
+ if (res_bar >= PCI_STD_NUM_BARS)
+ continue;
+
+ /* Type and ID match, and the BAR value isn't reserved.
+ * Looks good.
+ */
/* Read the lower 32bit of length and offset */
pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
@@ -337,6 +342,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
length_hi), &tmp32);
res_length |= ((u64)tmp32) << 32;
+ *bar = res_bar;
*offset = res_offset;
*len = res_length;
diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index e8b3ff2b9fbc..591738ad3d56 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -35,6 +35,13 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
&length);
+ /* Check if the BAR may have changed since we requested the region. */
+ if (bar >= PCI_STD_NUM_BARS || !(mdev->modern_bars & (1 << bar))) {
+ dev_err(&dev->dev,
+ "virtio_pci: bar unexpectedly changed to %u\n", bar);
+ return NULL;
+ }
+
if (length <= start) {
dev_err(&dev->dev,
"virtio_pci: bad capability len %u (>%u expected)\n",
@@ -120,7 +127,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
&bar);
/* Ignore structures with reserved BAR values */
- if (bar > 0x5)
+ if (bar >= PCI_STD_NUM_BARS)
continue;
if (type == cfg_type) {