[PATCH v4 21/21] mm: on remap assert that input range within the proposed VMA

[Lorenzo Stoakes (Oracle)]

Now we have range_in_vma_desc(), update remap_pfn_range_prepare() to check
whether the input range in contained within the specified VMA, so we can
fail at prepare time if an invalid range is specified.

This covers the I/O remap mmap actions also which ultimately call into
this function, and other mmap action types either already span the full
VMA or check this already.

Reviewed-by: Suren Baghdasaryan <surenb at google.com>
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs at kernel.org>
---
 mm/memory.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/memory.c b/mm/memory.c
index 53ef8ef3d04a..68cc592ff0ba 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3142,6 +3142,9 @@ int remap_pfn_range_prepare(struct vm_area_desc *desc)
 	const bool is_cow = vma_desc_is_cow_mapping(desc);
 	int err;
 
+	if (!range_in_vma_desc(desc, start, end))
+		return -EFAULT;
+
 	err = get_remap_pgoff(is_cow, start, end, desc->start, desc->end, pfn,
 			      &desc->pgoff);
 	if (err)
-- 
2.53.0