From: Alexey Kardashevskiy <a...@ozlabs.ru> [ Upstream commit 511d25d6b789fffcb20a3eb71899cf974a31bd9d ]
The userspace can trigger "vmalloc size %lu allocation failure: exceeds total pages" via the KVM_SET_USER_MEMORY_REGION ioctl. This silences the warning by checking the limit before calling vzalloc() and returns ENOMEM if failed. This does not call underlying valloc helpers as __vmalloc_node() is only exported when CONFIG_TEST_VMALLOC_MODULE and __vmalloc_node_range() is not exported at all. Spotted by syzkaller. Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> [mpe: Use 'size' for the variable rather than 'cb'] Signed-off-by: Michael Ellerman <m...@ellerman.id.au> Link: https://lore.kernel.org/r/20210901084512.1658628-1-...@ozlabs.ru Signed-off-by: Sasha Levin <sas...@kernel.org> --- arch/powerpc/kvm/book3s_hv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 7b74fc0a986b8..94da0d25eb125 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4861,8 +4861,12 @@ static int kvmppc_core_prepare_memory_region_hv(struct kvm *kvm, unsigned long npages = mem->memory_size >> PAGE_SHIFT; if (change == KVM_MR_CREATE) { - slot->arch.rmap = vzalloc(array_size(npages, - sizeof(*slot->arch.rmap))); + unsigned long size = array_size(npages, sizeof(*slot->arch.rmap)); + + if ((size >> PAGE_SHIFT) > totalram_pages()) + return -ENOMEM; + + slot->arch.rmap = vzalloc(size); if (!slot->arch.rmap) return -ENOMEM; } -- 2.34.1
