virt_addr_valid is supposed to return true if and only if virt_to_page returns a valid page structure. The current macro does math on whatever address is given and passes that to pfn_valid to verify. vmalloc and module addresses can happen to generate a pfn that 'happens' to be valid. Fix this by only performing the pfn_valid check on addresses that have the potential to be valid.
Signed-off-by: Laura Abbott <labb...@redhat.com> --- This caused a bug at least twice in hardened usercopy so it is an actual problem. A further TODO is full DEBUG_VIRTUAL support to catch these types of mistakes. --- arch/arm64/include/asm/memory.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 31b7322..f741e19 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -214,7 +214,7 @@ static inline void *phys_to_virt(phys_addr_t x) #ifndef CONFIG_SPARSEMEM_VMEMMAP #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) -#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) +#define virt_addr_valid(kaddr) (((u64)kaddr) >= PAGE_OFFSET && pfn_valid(__pa(kaddr) >> PAGE_SHIFT)) #else #define __virt_to_pgoff(kaddr) (((u64)(kaddr) & ~PAGE_OFFSET) / PAGE_SIZE * sizeof(struct page)) #define __page_to_voff(kaddr) (((u64)(page) & ~VMEMMAP_START) * PAGE_SIZE / sizeof(struct page)) @@ -222,8 +222,8 @@ static inline void *phys_to_virt(phys_addr_t x) #define page_to_virt(page) ((void *)((__page_to_voff(page)) | PAGE_OFFSET)) #define virt_to_page(vaddr) ((struct page *)((__virt_to_pgoff(vaddr)) | VMEMMAP_START)) -#define virt_addr_valid(kaddr) pfn_valid((((u64)(kaddr) & ~PAGE_OFFSET) \ - + PHYS_OFFSET) >> PAGE_SHIFT) +#define virt_addr_valid(kaddr) (((u64)kaddr) >= PAGE_OFFSET && pfn_valid((((u64)(kaddr) & ~PAGE_OFFSET) \ + + PHYS_OFFSET) >> PAGE_SHIFT)) #endif #endif -- 2.7.4
