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path: root/drivers/char/mem.c
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-rw-r--r--drivers/char/mem.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 970e1242a282..6aefe5370e5b 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -343,6 +343,10 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma)
size_t size = vma->vm_end - vma->vm_start;
phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
+ /* Does it even fit in phys_addr_t? */
+ if (offset >> PAGE_SHIFT != vma->vm_pgoff)
+ return -EINVAL;
+
/* It's illegal to wrap around the end of the physical address space. */
if (offset + (phys_addr_t)size - 1 < offset)
return -EINVAL;