From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
[ Upstream commit 96d3c1cadedb6ae2e8965e19cd12caa244afbd9c ]
The encode_dma() function has some validation on in_trans->size but it
would be more clear to move those checks to find_and_map_user_pages().
The encode_dma() had two checks:
if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size)
return -EINVAL;
The in_trans->addr variable is the starting address. The in_trans->size
variable is the total size of the transfer. The transfer can occur in
parts and the resources->xferred_dma_size tracks how many bytes we have
already transferred.
This patch introduces a new variable "remaining" which represents the
amount we want to transfer (in_trans->size) minus the amount we have
already transferred (resources->xferred_dma_size).
I have modified the check for if in_trans->size is zero to instead check
if in_trans->size is less than resources->xferred_dma_size. If we have
already transferred more bytes than in_trans->size then there are negative
bytes remaining which doesn't make sense. If there are zero bytes
remaining to be copied, just return success.
The check in encode_dma() checked that "addr + size" could not overflow
and barring a driver bug that should work, but it's easier to check if
we do this in parts. First check that "in_trans->addr +
resources->xferred_dma_size" is safe. Then check that "xfer_start_addr +
remaining" is safe.
My final concern was that we are dealing with u64 values but on 32bit
systems the kmalloc() function will truncate the sizes to 32 bits. So
I calculated "total = in_trans->size + offset_in_page(xfer_start_addr);"
and returned -EINVAL if it were >= SIZE_MAX. This will not affect 64bit
systems.
Fixes: 129776ac2e38 ("accel/qaic: Add control path")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
Reviewed-by: Carl Vanderlip <quic_carlv@xxxxxxxxxxx>
Signed-off-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/24d3348b-25ac-4c1b-b171-9dae7c43e4e0@moroto.mountain
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/accel/qaic/qaic_control.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index cfbc92da426fa..388abd40024ba 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -392,18 +392,31 @@ static int find_and_map_user_pages(struct qaic_device *qdev,
struct qaic_manage_trans_dma_xfer *in_trans,
struct ioctl_resources *resources, struct dma_xfer *xfer)
{
+ u64 xfer_start_addr, remaining, end, total;
unsigned long need_pages;
struct page **page_list;
unsigned long nr_pages;
struct sg_table *sgt;
- u64 xfer_start_addr;
int ret;
int i;
- xfer_start_addr = in_trans->addr + resources->xferred_dma_size;
+ if (check_add_overflow(in_trans->addr, resources->xferred_dma_size, &xfer_start_addr))
+ return -EINVAL;
- need_pages = DIV_ROUND_UP(in_trans->size + offset_in_page(xfer_start_addr) -
- resources->xferred_dma_size, PAGE_SIZE);
+ if (in_trans->size < resources->xferred_dma_size)
+ return -EINVAL;
+ remaining = in_trans->size - resources->xferred_dma_size;
+ if (remaining == 0)
+ return 0;
+
+ if (check_add_overflow(xfer_start_addr, remaining, &end))
+ return -EINVAL;
+
+ total = remaining + offset_in_page(xfer_start_addr);
+ if (total >= SIZE_MAX)
+ return -EINVAL;
+
+ need_pages = DIV_ROUND_UP(total, PAGE_SIZE);
nr_pages = need_pages;
@@ -435,7 +448,7 @@ static int find_and_map_user_pages(struct qaic_device *qdev,
ret = sg_alloc_table_from_pages(sgt, page_list, nr_pages,
offset_in_page(xfer_start_addr),
- in_trans->size - resources->xferred_dma_size, GFP_KERNEL);
+ remaining, GFP_KERNEL);
if (ret) {
ret = -ENOMEM;
goto free_sgt;
@@ -566,9 +579,6 @@ static int encode_dma(struct qaic_device *qdev, void *trans, struct wrapper_list
QAIC_MANAGE_EXT_MSG_LENGTH)
return -ENOMEM;
- if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size)
- return -EINVAL;
-
xfer = kmalloc(sizeof(*xfer), GFP_KERNEL);
if (!xfer)
return -ENOMEM;
--
2.40.1
