[PATCH 3.10 193/268] s390/pci: fix use after free in dma_init

Willy Tarreau
2017-06-19T19:05:30Z

From: Sebastian Ott <sebott@linux.vnet.ibm.com>

commit dba599091c191d209b1499511a524ad9657c0e5a upstream.

After a failure during registration of the dma_table (because of the
function being in error state) we free its memory but don't reset the
associated pointer to zero.

When we then receive a notification from firmware (about the function
being in error state) we'll try to walk and free the dma_table again.

Fix this by resetting the dma_table pointer. In addition to that make
sure that we free the iommu_bitmap when appropriate.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
arch/s390/pci/pci_dma.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index f8e69d5..aae199b 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -416,7 +416,7 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
zdev->dma_table = dma_alloc_cpu_table();
if (!zdev->dma_table) {
rc = -ENOMEM;
- goto out_clean;
+ goto out;
}

zdev->iommu_size = (unsigned long) high_memory - PAGE_OFFSET;
@@ -429,7 +429,7 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
bitmap_order);
if (!zdev->iommu_bitmap) {
rc = -ENOMEM;
- goto out_reg;
+ goto free_dma_table;
}

rc = zpci_register_ioat(zdev,
@@ -438,12 +438,16 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
zdev->start_dma + zdev->iommu_size - 1,
(u64) zdev->dma_table);
if (rc)
- goto out_reg;
- return 0;
+ goto free_bitmap;

-out_reg:
+ return 0;
+free_bitmap:
+ vfree(zdev->iommu_bitmap);
+ zdev->iommu_bitmap = NULL;
+free_dma_table:
dma_free_cpu_table(zdev->dma_table);
-out_clean:
+ zdev->dma_table = NULL;
+out:
return rc;
}

--
2.8.0.rc2.1.gbe9624a