Messages in this thread Patch in this message | | | Date | Fri, 3 Apr 2020 18:32:53 +0200 | From | Peter Zijlstra <> | Subject | [PATCH] mm/vmalloc: Sanitize __get_vm_area() arguments |
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__get_vm_area() is an exported symbol, make sure the callers stay in the expected memory range. When calling this function with memory ranges outside of the VMALLOC range *bad* things can happen.
(I noticed this when I managed to corrupt the kernel text by accident)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- mm/vmalloc.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2130,6 +2130,13 @@ static struct vm_struct *__get_vm_area_n struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, unsigned long start, unsigned long end) { + /* + * Ensure callers stay in the vmalloc range. + */ + if (WARN_ON(start < VMALLOC_START || start > VMALLOC_END || + end < VMALLOC_START || end > VMALLOC_END)) + return NULL; + return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE, GFP_KERNEL, __builtin_return_address(0)); }
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