From 18ba80533558af0cb186ccb71022fabfa9604ffe Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 19 Feb 2018 16:46:57 +0000 Subject: [PATCH] arm64: __show_regs: Only resolve kernel symbols when running at EL1 commit a06f818a70de21b4b3b4186816094208fc7accf9 upstream. __show_regs pretty prints PC and LR by attempting to map them to kernel function names to improve the utility of crash reports. Unfortunately, this mapping is applied even when the pt_regs corresponds to user mode, resulting in a KASLR oracle. Avoid this issue by only looking up the function symbols when the register state indicates that we're actually running at EL1. Reported-by: NCSC Security Signed-off-by: Will Deacon [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- arch/arm64/kernel/process.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 831a45e1f8e4..0bfb5fe5fdc7 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -197,8 +197,15 @@ void __show_regs(struct pt_regs *regs) } show_regs_print_info(KERN_DEFAULT); - printk("pc : %pS\n", (void *)regs->pc); - printk("lr : %pS\n", (void *)lr); + + if (!user_mode(regs)) { + printk("pc : %pS\n", (void *)regs->pc); + printk("lr : %pS\n", (void *)lr); + } else { + printk("pc : %016llx\n", regs->pc); + printk("lr : %016llx\n", lr); + } + printk("sp : %016llx pstate : %08llx\n", sp, regs->pstate); for (i = top_reg; i >= 0; i--) { printk("x%-2d: %016llx ", i, regs->regs[i]);