[PATCH v5 1/3] fpga: dfl: add bounds check in dfh_get_param_size()

[PATCH v5 1/3] fpga: dfl: add bounds check in dfh_get_param_size()

[Sebastian Alba Vives]

dfh_get_param_size() can return a parameter size larger than the feature
region because the loop bounds check is evaluated before incrementing
size. If the EOP (End of Parameters) bit is set in the same iteration,
the inflated size is returned without re-validation against max.

This can cause create_feature_instance() to call memcpy_fromio() with a
size exceeding the ioremap'd region when a malicious FPGA device provides
crafted DFHv1 parameter headers.

Add a bounds check after the size increment to ensure the accumulated
size never exceeds the feature boundary.

Fixes: a80a4b2b2e4f ("fpga: dfl: add support for DFHv1")
Signed-off-by: Sebastian Alba Vives <sebasjosue84@gmail.com>
---
Changes in v5:
  - Add blank line after the new bounds check.
    Suggested by Xu Yilun.
Changes in v4:
  - Resubmit as full series per maintainer request.
Changes in v2:
  - Use (size > max) instead of (size + DFHv1_PARAM_HDR > max).
    Suggested by Xu Yilun.
---
 drivers/fpga/dfl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 81d7a68..4c63c7c 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -1134,6 +1134,7 @@ static int dfh_get_param_size(void __iomem *dfh_base, resource_size_t max)
 		size += next * sizeof(u64);
 		if (size > max)
 			return -EINVAL;
+
 		if (FIELD_GET(DFHv1_PARAM_HDR_NEXT_EOP, v))
 			return size;
 	}
-- 
2.43.0

[PATCH v5 2/3] fpga: dfl-afu: validate DMA mapping length in afu_dma_map_region()

[Sebastian Alba Vives]

afu_ioctl_dma_map() accepts a 64-bit length from userspace via
DFL_FPGA_PORT_DMA_MAP ioctl without an upper bound check. The value
is passed to afu_dma_pin_pages() where npages is derived as
length >> PAGE_SHIFT and passed to pin_user_pages_fast() which takes
int nr_pages, causing implicit truncation if length is very large.

Validate map.length at the ioctl entry point before calling
afu_dma_map_region(), rejecting values whose page count exceeds
INT_MAX.

Signed-off-by: Sebastian Alba Vives <sebasjosue84@gmail.com>
---
Changes in v5:
  - Resubmit as full series with v5 corrections to patches 1/3 and 3/3.
    No changes to this patch.
Changes in v4:
  - Resubmit as full series per maintainer request.
Changes in v3:
  - Move validation to afu_ioctl_dma_map() at the ioctl entry point,
    before crossing the userspace/kernel boundary, instead of deep in
    afu_dma_pin_pages(). Suggested by Greg Kroah-Hartman.
Changes in v2:
  - Added cap at INT_MAX in afu_dma_pin_pages() (superseded by v3).
---
 drivers/fpga/dfl-afu-main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
index 3bf8e73..097a97e 100644
--- a/drivers/fpga/dfl-afu-main.c
+++ b/drivers/fpga/dfl-afu-main.c
@@ -723,6 +723,9 @@ afu_ioctl_dma_map(struct dfl_feature_dev_data *fdata, void __user *arg)
 	if (map.argsz < minsz || map.flags)
 		return -EINVAL;
 
+	if (map.length >> PAGE_SHIFT > (u64)INT_MAX)
+		return -EINVAL;
+
 	ret = afu_dma_map_region(fdata, map.user_addr, map.length, &map.iova);
 	if (ret)
 		return ret;
-- 
2.43.0

[PATCH v5 3/3] fpga: microchip-spi: fix zero header_size OOB read in mpf_ops_parse_header()

[Sebastian Alba Vives]

mpf_ops_parse_header() reads header_size from the bitstream at
MPF_HEADER_SIZE_OFFSET (24). When header_size is zero, the expression
*(buf + header_size - 1) reads one byte before the buffer start.

Since initial_header_size is set to 71 in mpf_ops, the fpga-mgr core
guarantees the buffer is always large enough to reach MPF_HEADER_SIZE_OFFSET.
The only real gap is the zero header_size case, which cannot be resolved
by providing a larger buffer, so return -EINVAL.

Fixes: 5f8d4a9008307 ("fpga: microchip-spi: add Microchip MPF FPGA manager")
Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Alba Vives <sebasjosue84@gmail.com>
---
Changes in v5:
  - Drop the count < MPF_HEADER_SIZE_OFFSET + 1 check. Since
    initial_header_size = 71 is set in mpf_ops, the fpga-mgr core
    already guarantees the buffer covers MPF_HEADER_SIZE_OFFSET.
    Only the zero header_size case remains as a genuine bug.
    Suggested by Xu Yilun.
Changes in v4:
  - Reduce to two minimal fixes: minimum count check and -EINVAL for
    zero header_size (superseded by v5).
Changes in v3:
  - Add overflow check for 32-bit in component size loop.
Changes in v2:
  - Return -EINVAL for header_size == 0, -EAGAIN in block loop,
    add count check before MPF_HEADER_SIZE_OFFSET read.
---
 drivers/fpga/microchip-spi.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c
index dca1a5d..cc8f6d7 100644
--- a/drivers/fpga/microchip-spi.c
+++ b/drivers/fpga/microchip-spi.c
@@ -115,9 +115,6 @@ static int mpf_ops_parse_header(struct fpga_manager *mgr,
 		return -EINVAL;
 	}
 
-	if (count < MPF_HEADER_SIZE_OFFSET + 1)
-		return -EINVAL;
-
 	header_size = *(buf + MPF_HEADER_SIZE_OFFSET);
 	if (!header_size)
 		return -EINVAL;
-- 
2.43.0

Re: [PATCH v5 1/3] fpga: dfl: add bounds check in dfh_get_param_size()

[Xu Yilun]

On Mon, May 04, 2026 at 06:13:30AM -0600, Sebastian Alba Vives wrote:
> dfh_get_param_size() can return a parameter size larger than the feature
> region because the loop bounds check is evaluated before incrementing
> size. If the EOP (End of Parameters) bit is set in the same iteration,
> the inflated size is returned without re-validation against max.
> 
> This can cause create_feature_instance() to call memcpy_fromio() with a
> size exceeding the ioremap'd region when a malicious FPGA device provides
> crafted DFHv1 parameter headers.
> 
> Add a bounds check after the size increment to ensure the accumulated
> size never exceeds the feature boundary.
> 
> Fixes: a80a4b2b2e4f ("fpga: dfl: add support for DFHv1")
> Signed-off-by: Sebastian Alba Vives <sebasjosue84@gmail.com>
> ---
> Changes in v5:
>   - Add blank line after the new bounds check.
>     Suggested by Xu Yilun.
> Changes in v4:
>   - Resubmit as full series per maintainer request.
> Changes in v2:
>   - Use (size > max) instead of (size + DFHv1_PARAM_HDR > max).
>     Suggested by Xu Yilun.
> ---
>  drivers/fpga/dfl.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index 81d7a68..4c63c7c 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -1134,6 +1134,7 @@ static int dfh_get_param_size(void __iomem *dfh_base, resource_size_t max)
>  		size += next * sizeof(u64);
>  		if (size > max)
>  			return -EINVAL;
> +

Hey, please provide a patch that can apply to linux-next. I can do
nothing to your series. Please read Documentation/process/ before
submit.

Also, please make a cover-letter (Patch #0) when you make the patch
series.

>  		if (FIELD_GET(DFHv1_PARAM_HDR_NEXT_EOP, v))
>  			return size;
>  	}
> -- 
> 2.43.0
>