[PATCH] irq: ipi: fix NULL pointer deref in irq_data_get_affinity_mask()

From: Sergey Shtylyov
Date: Wed Aug 17 2022 - 16:01:03 EST


Iff ipi_send_{mask|single}() get called with e.g. an invalid IRQ #, all the
local variables there will be NULL -- the problem is that ipi_send_verify()
(that's called first thing) doesn't verify its 'data' parameter, resulting
in a kernel oops in irq_data_get_affinity_mask() as the passed NULL pointer
gets dereferenced. Add a missing NULL check in ipi_send_verify()...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Fixes: 3b8e29a82dd1 ("genirq: Implement ipi_send_mask/single()")
Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxx>

---
The patch is against the 'tip.git' repo's 'master' branch...

kernel/irq/ipi.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

Index: tip/kernel/irq/ipi.c
===================================================================
--- tip.orig/kernel/irq/ipi.c
+++ tip/kernel/irq/ipi.c
@@ -188,9 +188,9 @@ EXPORT_SYMBOL_GPL(ipi_get_hwirq);
static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
const struct cpumask *dest, unsigned int cpu)
{
- const struct cpumask *ipimask = irq_data_get_affinity_mask(data);
+ const struct cpumask *ipimask;

- if (!chip || !ipimask)
+ if (!chip || !data)
return -EINVAL;

if (!chip->ipi_send_single && !chip->ipi_send_mask)
@@ -199,6 +199,10 @@ static int ipi_send_verify(struct irq_ch
if (cpu >= nr_cpu_ids)
return -EINVAL;

+ ipimask = irq_data_get_affinity_mask(data);
+ if (!ipimask)
+ return -EINVAL;
+
if (dest) {
if (!cpumask_subset(dest, ipimask))
return -EINVAL;