• Catalin Marinas's avatar
    arm64: kasan: Fix zero shadow mapping overriding kernel image shadow · 2776e0e8
    Catalin Marinas authored
    With the 16KB and 64KB page size configurations, SWAPPER_BLOCK_SIZE is
    PAGE_SIZE and ARM64_SWAPPER_USES_SECTION_MAPS is 0. Since
    kimg_shadow_end is not page aligned (_end shifted by
    KASAN_SHADOW_SCALE_SHIFT), the edges of previously mapped kernel image
    shadow via vmemmap_populate() may be overridden by subsequent calls to
    kasan_populate_zero_shadow(), leading to kernel panics like below:
    
    ------------------------------------------------------------------------------
    Unable to handle kernel paging request at virtual address fffffc100135068c
    pgd = fffffc8009ac0000
    [fffffc100135068c] *pgd=00000009ffee0003, *pud=00000009ffee0003, *pmd=00000009ffee0003, *pte=00e0000081a00793
    Internal error: Oops: 9600004f [#1] PREEMPT SMP
    Modules linked in:
    CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc4+ #1984
    Hardware name: Juno (DT)
    task: fffffe09001a0000 ti: fffffe0900200000 task.ti: fffffe0900200000
    PC is at __memset+0x4c/0x200
    LR is at kasan_unpoison_shadow+0x34/0x50
    pc : [<fffffc800846f1cc>] lr : [<fffffc800821ff54>] pstate: 00000245
    sp : fffffe0900203db0
    x29: fffffe0900203db0 x28: 0000000000000000
    x27: 0000000000000000 x26: 0000000000000000
    x25: fffffc80099b69d0 x24: 0000000000000001
    x23: 0000000000000000 x22: 0000000000002000
    x21: dffffc8000000000 x20: 1fffff9001350a8c
    x19: 0000000000002000 x18: 0000000000000008
    x17: 0000000000000147 x16: ffffffffffffffff
    x15: 79746972100e041d x14: ffffff0000000000
    x13: ffff000000000000 x12: 0000000000000000
    x11: 0101010101010101 x10: 1fffffc11c000000
    x9 : 0000000000000000 x8 : fffffc100135068c
    x7 : 0000000000000000 x6 : 000000000000003f
    x5 : 0000000000000040 x4 : 0000000000000004
    x3 : fffffc100134f651 x2 : 0000000000000400
    x1 : 0000000000000000 x0 : fffffc100135068c
    
    Process swapper/0 (pid: 1, stack limit = 0xfffffe0900200020)
    Call trace:
    [<fffffc800846f1cc>] __memset+0x4c/0x200
    [<fffffc8008220044>] __asan_register_globals+0x5c/0xb0
    [<fffffc8008a09d34>] _GLOBAL__sub_I_65535_1_sunrpc_cache_lookup+0x1c/0x28
    [<fffffc8008f20d28>] kernel_init_freeable+0x104/0x274
    [<fffffc80089e1948>] kernel_init+0x10/0xf8
    [<fffffc8008093a00>] ret_from_fork+0x10/0x50
    ------------------------------------------------------------------------------
    
    This patch aligns kimg_shadow_start and kimg_shadow_end to
    SWAPPER_BLOCK_SIZE in all configurations.
    
    Fixes: f9040773 ("arm64: move kernel image to base of vmalloc area")
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
    Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
    2776e0e8
kasan_init.c 5.93 KB