From 883ea134ae75eb03c9f08553a81957a808cee96b Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 23 Jun 2014 15:29:40 +0200 Subject: [PATCH] s390/ptrace: fix PSW mask check commit dab6cf55f81a6e16b8147aed9a843e1691dcd318 upstream. The PSW mask check of the PTRACE_POKEUSR_AREA command is incorrect. The PSW_MASK_USER define contains the PSW_MASK_ASC bits, the ptrace interface accepts all combinations for the address-space-control bits. To protect the kernel space the PSW mask check in ptrace needs to reject the address-space-control bit combination for home space. Fixes CVE-2014-3534 Signed-off-by: Martin Schwidefsky Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/ptrace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 02f300f..e0a8707 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -292,7 +292,9 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data) * psw and gprs are stored on the stack */ if (addr == (addr_t) &dummy->regs.psw.mask && - ((data & ~PSW_MASK_USER) != psw_user_bits || + (((data^psw_user_bits) & ~PSW_MASK_USER) || + (((data^psw_user_bits) & PSW_MASK_ASC) && + ((data|psw_user_bits) & PSW_MASK_ASC) == PSW_MASK_ASC) || ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA)))) /* Invalid psw mask. */ return -EINVAL; @@ -595,7 +597,10 @@ static int __poke_user_compat(struct task_struct *child, */ if (addr == (addr_t) &dummy32->regs.psw.mask) { /* Build a 64 bit psw mask from 31 bit mask. */ - if ((tmp & ~PSW32_MASK_USER) != psw32_user_bits) + if (((tmp^psw32_user_bits) & ~PSW32_MASK_USER) || + (((tmp^psw32_user_bits) & PSW32_MASK_ASC) && + ((tmp|psw32_user_bits) & PSW32_MASK_ASC) + == PSW32_MASK_ASC)) /* Invalid psw mask. */ return -EINVAL; regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) | -- 2.7.4