2022-02-25 09:24:22

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH] arch: x86: xen: check the return value of kasprintf()

The function kasprintf() can fail, but there is no check of its return
value. To fix this bug, its return value should be checked with new
error handling code.

Fixes: f87e4cac4f4e ("xen: SMP guest support")
Fixes: 83b96794e0ea ("x86/xen: split off smp_pv.c")
Fixes: d5de8841355a ("x86: split spinlock implementations out into their own files")
Reported-by: TOTE Robot <[email protected]>
Signed-off-by: Jia-Ju Bai <[email protected]>
---
arch/x86/xen/smp.c | 2 ++
arch/x86/xen/smp_pv.c | 2 ++
arch/x86/xen/spinlock.c | 2 ++
3 files changed, 6 insertions(+)

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index c3e1f9a7d43a..91261390f8c0 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -65,6 +65,8 @@ int xen_smp_intr_init(unsigned int cpu)
char *resched_name, *callfunc_name, *debug_name;

resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
+ if (!resched_name)
+ return -ENOMEM;
rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
cpu,
xen_reschedule_interrupt,
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 4a6019238ee7..7d1471fd1267 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -118,6 +118,8 @@ int xen_smp_intr_init_pv(unsigned int cpu)
char *callfunc_name, *pmu_name;

callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
+ if (!callfunc_name)
+ return -ENOMEM;
rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
cpu,
xen_irq_work_interrupt,
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 043c73dfd2c9..ccdb9eddd93b 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -75,6 +75,8 @@ void xen_init_lock_cpu(int cpu)
cpu, per_cpu(lock_kicker_irq, cpu));

name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
+ if (!name)
+ return;
irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
cpu,
dummy_handler,
--
2.17.1


2022-02-25 21:38:28

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH] arch: x86: xen: check the return value of kasprintf()

On 25.02.22 09:11, Jia-Ju Bai wrote:
> The function kasprintf() can fail, but there is no check of its return
> value. To fix this bug, its return value should be checked with new
> error handling code.
>
> Fixes: f87e4cac4f4e ("xen: SMP guest support")
> Fixes: 83b96794e0ea ("x86/xen: split off smp_pv.c")
> Fixes: d5de8841355a ("x86: split spinlock implementations out into their own files")
> Reported-by: TOTE Robot <[email protected]>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> ---
> arch/x86/xen/smp.c | 2 ++
> arch/x86/xen/smp_pv.c | 2 ++
> arch/x86/xen/spinlock.c | 2 ++
> 3 files changed, 6 insertions(+)
>
> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
> index c3e1f9a7d43a..91261390f8c0 100644
> --- a/arch/x86/xen/smp.c
> +++ b/arch/x86/xen/smp.c
> @@ -65,6 +65,8 @@ int xen_smp_intr_init(unsigned int cpu)
> char *resched_name, *callfunc_name, *debug_name;
>
> resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
> + if (!resched_name)
> + return -ENOMEM;

There are 3 more instances of kasprintf() in this function.

> rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
> cpu,
> xen_reschedule_interrupt,
> diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
> index 4a6019238ee7..7d1471fd1267 100644
> --- a/arch/x86/xen/smp_pv.c
> +++ b/arch/x86/xen/smp_pv.c
> @@ -118,6 +118,8 @@ int xen_smp_intr_init_pv(unsigned int cpu)
> char *callfunc_name, *pmu_name;
>
> callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
> + if (!callfunc_name)
> + return -ENOMEM;

And in here is another one, too.

> rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
> cpu,
> xen_irq_work_interrupt,
> diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
> index 043c73dfd2c9..ccdb9eddd93b 100644
> --- a/arch/x86/xen/spinlock.c
> +++ b/arch/x86/xen/spinlock.c
> @@ -75,6 +75,8 @@ void xen_init_lock_cpu(int cpu)
> cpu, per_cpu(lock_kicker_irq, cpu));
>
> name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
> + if (!name)
> + return;

Just failing silently is not nice.

> irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
> cpu,
> dummy_handler,


Juergen


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