[tip: irq/urgent] genirq/ipi: Fix NULL pointer deref in irq_data_get_affinity_mask()

[tip-bot2 for Sergey Shtylyov]

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     feabecaff5902f896531dde90646ca5dfa9d4f7d
Gitweb:        https://git.kernel.org/tip/feabecaff5902f896531dde90646ca5dfa9d4f7d
Author:        Sergey Shtylyov <s.shtylyov@xxxxxx>
AuthorDate:    Wed, 17 Aug 2022 23:00:45 +03:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 20 Feb 2023 13:53:41 +01:00

genirq/ipi: Fix NULL pointer deref in irq_data_get_affinity_mask()

If ipi_send_{mask|single}() is called with an invalid interrupt number, all
the local variables there will be NULL. ipi_send_verify() which is invoked
from these functions does 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 pointer 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>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/b541232d-c2b6-1fe9-79b4-a7129459e4d0@xxxxxx


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

diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c
index bbd945b..961d4af 100644
--- a/kernel/irq/ipi.c
+++ b/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_chip *chip, struct irq_data *data,
 	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;