From 4a23e56ad6549d0b8c0fac6d9eb752884379c391 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 18 Aug 2017 18:42:30 +0100 Subject: arm64: kaslr: ignore modulo offset when validating virtual displacement In the KASLR setup routine, we ensure that the early virtual mapping of the kernel image does not cover more than a single table entry at the level above the swapper block level, so that the assembler routines involved in setting up this mapping can remain simple. In this calculation we add the proposed KASLR offset to the values of the _text and _end markers, and reject it if they would end up falling in different swapper table sized windows. However, when taking the addresses of _text and _end, the modulo offset (the physical displacement modulo 2 MB) is already accounted for, and so adding it again results in incorrect results. So disregard the modulo offset from the calculation. Fixes: 08cdac619c81 ("arm64: relocatable: deal with physically misaligned ...") Reviewed-by: Catalin Marinas Tested-by: Catalin Marinas Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon --- arch/arm64/kernel/head.S | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/arm64/kernel/head.S') diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 973df7de7bf8..adb0910b88f5 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -354,7 +354,6 @@ __primary_switched: tst x23, ~(MIN_KIMG_ALIGN - 1) // already running randomized? b.ne 0f mov x0, x21 // pass FDT address in x0 - mov x1, x23 // pass modulo offset in x1 bl kaslr_early_init // parse FDT for KASLR options cbz x0, 0f // KASLR disabled? just proceed orr x23, x23, x0 // record KASLR offset -- cgit v1.2.3