From 6fafb8befa99620a2d7323b9eca5c387bad1f59f Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 13 May 2019 16:41:03 +0200 Subject: [PATCH] x86/IRQ: avoid UB (or worse) in trace_irq_mask() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Dynamically allocated CPU mask objects may be smaller than cpumask_t, so copying has to be restricted to the actual allocation size. This is particulary important since the function doesn't bail early when tracing is not active, so even production builds would be affected by potential misbehavior here. Take the opportunity and also - use initializers instead of assignment + memset(), - constify the cpumask_t input pointer, - u32 -> uint32_t. Signed-off-by: Jan Beulich Reviewed-by: Roger Pau Monné Acked-by: George Dunlap --- xen/arch/x86/irq.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c index 8511953977..0035174d1f 100644 --- a/xen/arch/x86/irq.c +++ b/xen/arch/x86/irq.c @@ -99,16 +99,19 @@ void unlock_vector_lock(void) spin_unlock(&vector_lock); } -static void trace_irq_mask(u32 event, int irq, int vector, cpumask_t *mask) +static void trace_irq_mask(uint32_t event, int irq, int vector, + const cpumask_t *mask) { struct { unsigned int irq:16, vec:16; unsigned int mask[6]; - } d; - d.irq = irq; - d.vec = vector; - memset(d.mask, 0, sizeof(d.mask)); - memcpy(d.mask, mask, min(sizeof(d.mask), sizeof(cpumask_t))); + } d = { + .irq = irq, + .vec = vector, + }; + + memcpy(d.mask, mask, + min(sizeof(d.mask), BITS_TO_LONGS(nr_cpu_ids) * sizeof(long))); trace_var(event, 1, sizeof(d), &d); } -- 2.30.2