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-rw-r--r--arch/ia64/kernel/ptrace.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index c253fd5914fc..9e730c7bf0cd 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -705,12 +705,32 @@ 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