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| author | Jean-Philippe Brucker <jean-philippe.brucker@arm.com> | 2018-06-19 15:52:24 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2018-07-26 13:34:58 +0300 |
| commit | 29859aeb8a6ea17ba207933a81b6b77b4d4df81a (patch) | |
| tree | a2a556c2138d72570abb71760f9385464943e201 /drivers/iommu | |
| parent | fac83d29d95471ad6a104f8c0d21669a3d59097b (diff) | |
| download | linux-29859aeb8a6ea17ba207933a81b6b77b4d4df81a.tar.xz | |
iommu/io-pgtable-arm-v7s: Abort allocation when table address overflows the PTE
When run on a 64-bit system in selftest, the v7s driver may obtain page
table with physical addresses larger than 32-bit. Level-2 tables are 1KB
and are are allocated with slab, which doesn't accept the GFP_DMA32
flag. Currently map() truncates the address written in the PTE, causing
iova_to_phys() or unmap() to access invalid memory. Kasan reports it as
a use-after-free. To avoid any nasty surprise, test if the physical
address fits in a PTE before returning a new table. 32-bit systems,
which are the main users of this page table format, shouldn't see any
difference.
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/io-pgtable-arm-v7s.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c index 50e3a9fcf43e..b5948ba6b3b3 100644 --- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -192,6 +192,7 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp, { struct io_pgtable_cfg *cfg = &data->iop.cfg; struct device *dev = cfg->iommu_dev; + phys_addr_t phys; dma_addr_t dma; size_t size = ARM_V7S_TABLE_SIZE(lvl); void *table = NULL; @@ -200,6 +201,10 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp, table = (void *)__get_dma_pages(__GFP_ZERO, get_order(size)); else if (lvl == 2) table = kmem_cache_zalloc(data->l2_tables, gfp | GFP_DMA); + phys = virt_to_phys(table); + if (phys != (arm_v7s_iopte)phys) + /* Doesn't fit in PTE */ + goto out_free; if (table && !(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA)) { dma = dma_map_single(dev, table, size, DMA_TO_DEVICE); if (dma_mapping_error(dev, dma)) @@ -209,7 +214,7 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp, * address directly, so if the DMA layer suggests otherwise by * translating or truncating them, that bodes very badly... */ - if (dma != virt_to_phys(table)) + if (dma != phys) goto out_unmap; } kmemleak_ignore(table); |