[PATCH -next] KVM: arm64: Fix possible null-ptr-deref in idregs_debug_show
Marc Zyngier
maz at kernel.org
Thu Oct 24 02:29:35 PDT 2024
On Thu, 24 Oct 2024 09:33:50 +0100,
Gaosheng Cui <cuigaosheng1 at huawei.com> wrote:
>
> The idregs_debug_show() maybe return nullptr, we need to check desc
> before dereference it to avoid possible null pointer dereferences.
>
> Fixes: 410db103f6eb ("KVM: arm64: Make idregs debugfs iterator search sysreg table directly")
> Signed-off-by: Gaosheng Cui <cuigaosheng1 at huawei.com>
> ---
> arch/arm64/kvm/sys_regs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index ff8c4e1b847e..b1c59773b9c0 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -4135,7 +4135,7 @@ static int idregs_debug_show(struct seq_file *s, void *v)
>
> desc = idregs_debug_find(kvm, kvm->arch.idreg_debugfs_iter);
>
> - if (!desc->name)
> + if (!desc || !desc->name)
> return 0;
>
> seq_printf(s, "%20s:\t%016llx\n",
Can you show a case where this happens in practice?
The check for NULL is already in idregs_debug_next(), and I don't see
how this can actually be triggered.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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