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

[Sergey Shtylyov]

On 2/20/23 3:55 PM, tip-bot2 for Sergey Shtylyov wrote:
> 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
                       ^^^^
   Looks like you spoiled the commit log: it should be "doesn't" -- as in my
original patch. :-/

> 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;

MBR, Sergey