[RFC PATCH 2/6] [ARM] mm/mmap.c: Check length of unmapped area before allowing MAP_FIXED
From: Liam Howlett <hidden>
Date: 2021-12-06 15:05:27
Also in:
lkml
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
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 <redacted> --- arch/arm/mm/mmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
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);
--
2.30.2
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