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RDMA/mlx5: Prevent overflow in mmap offset calculations

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The cmd and index variables declared as u16 and the result is supposed to
be stored in u64. The C arithmetic rules doesn't promote "(index >> 8) <<
16" to be u64 and leaves the end result to be u16.

Fixes: 7be76bef32 ("IB/mlx5: Introduce VAR object and its alloc/destroy methods")
Link: https://lore.kernel.org/r/20200212072635.682689-10-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Leon Romanovsky
2020-02-12 09:26:35 +02:00
committed by Jason Gunthorpe
parent 9ea04d0df6
commit 9b6d3bbc13
1 changed files with 2 additions and 2 deletions
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4
drivers/infiniband/hw/mlx5/main.c
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@@ -2283,8 +2283,8 @@ static int mlx5_ib_mmap_offset(struct mlx5_ib_dev *dev,
static u64 mlx5_entry_to_mmap_offset(struct mlx5_user_mmap_entry *entry)
{
u16 cmd = entry->rdma_entry.start_pgoff >> 16;
u16 index = entry->rdma_entry.start_pgoff & 0xFFFF;
u64 cmd = (entry->rdma_entry.start_pgoff >> 16) & 0xFFFF;
u64 index = entry->rdma_entry.start_pgoff & 0xFFFF;
return (((index >> 8) << 16) | (cmd << MLX5_IB_MMAP_CMD_SHIFT) |
(index & 0xFF)) << PAGE_SHIFT;