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Subject[RFC PATCH 3/6] nds32/mm/mmap.c: Check length of unmapped area before allowing MAP_FIXED
Date
arch_get_unmapped_area() could potentially allow a larger than possible
length when using the MAP_FIXED flag. The bound check should come
before the check for MAP_FIXED.

Fixes: 664eec400bf8 (nds32: MMU fault handling and page table
management)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
arch/nds32/mm/mmap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/nds32/mm/mmap.c b/arch/nds32/mm/mmap.c
index 1bdf5e7d1b43..1bc5a82ac3d3 100644
--- a/arch/nds32/mm/mmap.c
+++ b/arch/nds32/mm/mmap.c
@@ -31,6 +31,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
if(IS_ENABLED(CONFIG_CPU_CACHE_ALIASING))
aliasing = 1;

+ if (len > TASK_SIZE)
+ return -ENOMEM;
+
/*
* We only need to do colour alignment if either the I or D
* caches alias.
@@ -48,9 +51,6 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
return addr;
}

- if (len > TASK_SIZE)
- return -ENOMEM;
-
if (addr) {
if (do_align)
addr = COLOUR_ALIGN(addr, pgoff);
--
2.30.2
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