Commit 7a7003b1 authored Nov 02, 2017 by Mark Rutland Committed by Catalin Marinas Nov 02, 2017

arm64: ensure __dump_instr() checks addr_limit



It's possible for a user to deliberately trigger __dump_instr with a
chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

Where we use __dump_instr() on kernel text, we already switch to
KERNEL_DS, so this shouldn't adversely affect those cases.

Fixes: 60ffc30d ("arm64: Exception handling")
Cc: stable@vger.kernel.org
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent 0b07194b

arch/arm64/kernel/traps.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -118,7 +118,7 @@ static void __dump_instr(const char lvl, struct pt_regs regs)
		for (i = -4; i < 1; i++) {
		unsigned int val, bad;

		bad = __get_user(val, &((u32 *)addr)[i]);
		bad = get_user(val, &((u32 *)addr)[i]);

		if (!bad)
		p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);