diff mbox series

[RFC,2/6,ARM] mm/mmap.c: Check length of unmapped area before allowing MAP_FIXED

Message ID 20211206150231.2283069-3-Liam.Howlett@oracle.com (mailing list archive)
State New, archived
Headers show
Series Check length of unmapped area on MAP_FIXED | expand

Commit Message

Liam R. Howlett Dec. 6, 2021, 3:02 p.m. UTC 
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: 4fbe66759b2a ([ARM] Fix shared mmap()ings for ARM VIPT caches.)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 arch/arm/mm/mmap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index a0f8a0ca0788..cb135556ce36 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -36,6 +36,9 @@  arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	int aliasing = cache_is_vipt_aliasing();
 	struct vm_unmapped_area_info info;
 
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
 	/*
 	 * We only need to do colour alignment if either the I or D
 	 * caches alias.
@@ -53,9 +56,6 @@  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);