diff options
| author | Songtang Liu <liusongtang@bytedance.com> | 2025-10-30 22:55:25 -0700 |
|---|---|---|
| committer | Joerg Roedel <joerg.roedel@amd.com> | 2025-11-04 11:06:00 +0100 |
| commit | a0c7005333f9a968abb058b1d77bbcd7fb7fd1e7 (patch) | |
| tree | 7e5864a83d418bbbd20183e077719f472e08f09e | |
| parent | dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa (diff) | |
iommu/amd: Fix potential out-of-bounds read in iommu_mmio_show
In iommu_mmio_write(), it validates the user-provided offset with the
check: `iommu->dbg_mmio_offset > iommu->mmio_phys_end - 4`.
This assumes a 4-byte access. However, the corresponding
show handler, iommu_mmio_show(), uses readq() to perform an 8-byte
(64-bit) read.
If a user provides an offset equal to `mmio_phys_end - 4`, the check
passes, and will lead to a 4-byte out-of-bounds read.
Fix this by adjusting the boundary check to use sizeof(u64), which
corresponds to the size of the readq() operation.
Fixes: 7a4ee419e8c1 ("iommu/amd: Add debugfs support to dump IOMMU MMIO registers")
Signed-off-by: Songtang Liu <liusongtang@bytedance.com>
Reviewed-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Tested-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
| -rw-r--r-- | drivers/iommu/amd/debugfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/iommu/amd/debugfs.c b/drivers/iommu/amd/debugfs.c index 10fa217a7119..20b04996441d 100644 --- a/drivers/iommu/amd/debugfs.c +++ b/drivers/iommu/amd/debugfs.c @@ -37,7 +37,7 @@ static ssize_t iommu_mmio_write(struct file *filp, const char __user *ubuf, if (ret) return ret; - if (iommu->dbg_mmio_offset > iommu->mmio_phys_end - 4) { + if (iommu->dbg_mmio_offset > iommu->mmio_phys_end - sizeof(u64)) { iommu->dbg_mmio_offset = -1; return -EINVAL; } |