Fix NULL dereference which allows user programs to read parts

of the kernel memory.  Found with clang static analyzer.

Feedback and ok gkoehler@
ok bluhm@

diff --git a/sys/arch/powerpc/powerpc/trap.c b/sys/arch/powerpc/powerpc/trap.c
index 6e12ceb..990615f 100644 (file)
--- a/sys/arch/powerpc/powerpc/trap.c
+++ b/sys/arch/powerpc/powerpc/trap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: trap.c,v 1.124 2022/01/20 14:02:51 tobhe Exp $        */
+/*     $OpenBSD: trap.c,v 1.125 2022/01/21 14:07:06 tobhe Exp $        */
 /*     $NetBSD: trap.c,v 1.3 1996/10/13 03:31:37 christos Exp $        */
 
 /*
@@ -154,7 +154,7 @@ void
 enable_vec(struct proc *p)
 {
        struct pcb *pcb = &p->p_addr->u_pcb;
-       struct vreg *pcb_vr = pcb->pcb_vr;
+       struct vreg *pcb_vr;
        struct cpu_info *ci = curcpu();
        u_int32_t oldmsr, msr;
 
@@ -163,6 +163,7 @@ enable_vec(struct proc *p)
         */
        if (pcb->pcb_vr == NULL)
                pcb->pcb_vr = pool_get(&ppc_vecpl, PR_WAITOK | PR_ZERO);
+       pcb_vr = pcb->pcb_vr;
 
        if (curcpu()->ci_vecproc != NULL || pcb->pcb_veccpu != NULL)
                printf("attempting to restore vector in use vecproc %p"