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Anders Roxell authored
Commit 1404d6f1 ("arm64: dump: Add checking for writable and exectuable pages") has successfully identified code that leaves a page with W+X permissions. [ 3.245140] arm64/mm: Found insecure W+X mapping at address (____ptrval____)/0xffff000000d90000 [ 3.245771] WARNING: CPU: 0 PID: 1 at ../arch/arm64/mm/dump.c:232 note_page+0x410/0x420 [ 3.246141] Modules linked in: [ 3.246653] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc5-next-20180928-00001-ge70ae259b853-dirty #62 [ 3.247008] Hardware name: linux,dummy-virt (DT) [ 3.247347] pstate: 80000005 (Nzcv daif -PAN -UAO) [ 3.247623] pc : note_page+0x410/0x420 [ 3.247898] lr : note_page+0x410/0x420 [ 3.248071] sp : ffff00000804bcd0 [ 3.248254] x29: ffff00000804bcd0 x28: ffff000009274000 [ 3.248578] x27: ffff00000921a000 x26: ffff80007dfff000 [ 3.248845] x25: ffff0000093f5000 x24: ffff000009526f6a [ 3.249109] x23: 0000000000000004 x22: ffff000000d91000 [ 3.249396] x21: ffff000000d90000 x20: 0000000000000000 [ 3.249661] x19: ffff00000804bde8 x18: 0000000000000400 [ 3.249924] x17: 0000000000000000 x16: 0000000000000000 [ 3.250271] x15: ffffffffffffffff x14: 295f5f5f5f6c6176 [ 3.250594] x13: 7274705f5f5f5f28 x12: 2073736572646461 [ 3.250941] x11: 20746120676e6970 x10: 70616d20582b5720 [ 3.251252] x9 : 6572756365736e69 x8 : 3039643030303030 [ 3.251519] x7 : 306666666678302f x6 : ffff0000095467b2 [ 3.251802] x5 : 0000000000000000 x4 : 0000000000000000 [ 3.252060] x3 : 0000000000000000 x2 : ffffffffffffffff [ 3.252323] x1 : 4d151327adc50b00 x0 : 0000000000000000 [ 3.252664] Call trace: [ 3.252953] note_page+0x410/0x420 [ 3.253186] walk_pgd+0x12c/0x238 [ 3.253417] ptdump_check_wx+0x68/0xf8 [ 3.253637] mark_rodata_ro+0x68/0x98 [ 3.253847] kernel_init+0x38/0x160 [ 3.254103] ret_from_fork+0x10/0x18 kprobes allocates a writable executable page with module_alloc() in order to store executable code. Reworked to that when allocate a page it sets mode RO. Inspired by commit 63fef14f ("kprobes/x86: Make insn buffer always ROX and use text_poke()"). Suggested-by:
Arnd Bergmann <arnd@arndb.de> Suggested-by:
Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by:
Will Deacon <will.deacon@arm.com> Acked-by:
Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by:
Laura Abbott <labbott@redhat.com> Signed-off-by:
Anders Roxell <anders.roxell@linaro.org> [catalin.marinas@arm.com: removed unnecessary casts] Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
96686689