diff options
Diffstat (limited to 'arch/ia64/kernel/ptrace.c')
| -rw-r--r-- | arch/ia64/kernel/ptrace.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c index 575a8f657b31..4c1d2f5442b3 100644 --- a/arch/ia64/kernel/ptrace.c +++ b/arch/ia64/kernel/ptrace.c @@ -725,12 +725,32 @@ convert_to_non_syscall (struct task_struct *child, struct pt_regs *pt, break; } + /* + * Note: at the time of this call, the target task is blocked + * in notify_resume_user() and by clearling PRED_LEAVE_SYSCALL + * (aka, "pLvSys") we redirect execution from + * .work_pending_syscall_end to .work_processed_kernel. + */ unw_get_pr(&prev_info, &pr); - pr &= ~(1UL << PRED_SYSCALL); + pr &= ~((1UL << PRED_SYSCALL) | (1UL << PRED_LEAVE_SYSCALL)); pr |= (1UL << PRED_NON_SYSCALL); unw_set_pr(&prev_info, pr); pt->cr_ifs = (1UL << 63) | cfm; + /* + * Clear the memory that is NOT written on syscall-entry to + * ensure we do not leak kernel-state to user when execution + * resumes. + */ + pt->r2 = 0; + pt->r3 = 0; + pt->r14 = 0; + memset(&pt->r16, 0, 16*8); /* clear r16-r31 */ + memset(&pt->f6, 0, 6*16); /* clear f6-f11 */ + pt->b7 = 0; + pt->ar_ccv = 0; + pt->ar_csd = 0; + pt->ar_ssd = 0; } static int |