[PATCH V1] accel/amdxdna: Prevent ubuf size overflow

[Lizhi Hou]

The ubuf size calculation may overflow, resulting in an undersized
allocation and possible memory corruption.

Use check_add_overflow() helpers to validate the size calculation before
allocation.

Fixes: bd72d4acda10 ("accel/amdxdna: Support user space allocated buffer")
Signed-off-by: Lizhi Hou <lizhi....@amd.com>
---
 drivers/accel/amdxdna/amdxdna_ubuf.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/accel/amdxdna/amdxdna_ubuf.c 
b/drivers/accel/amdxdna/amdxdna_ubuf.c
index 9e3b3b055caa..62a478f6b45f 100644
--- a/drivers/accel/amdxdna/amdxdna_ubuf.c
+++ b/drivers/accel/amdxdna/amdxdna_ubuf.c
@@ -7,6 +7,7 @@
 #include <drm/drm_device.h>
 #include <drm/drm_print.h>
 #include <linux/dma-buf.h>
+#include <linux/overflow.h>
 #include <linux/pagemap.h>
 #include <linux/vmalloc.h>
 
@@ -176,7 +177,10 @@ struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
                        goto free_ent;
                }
 
-               exp_info.size += va_ent[i].len;
+               if (check_add_overflow(exp_info.size, va_ent[i].len, 
&exp_info.size)) {
+                       ret = -EINVAL;
+                       goto free_ent;
+               }
        }
 
        ubuf->nr_pages = exp_info.size >> PAGE_SHIFT;
-- 
2.34.1