[PATCH 5.0 069/117] kvm: svm: fix potential get_num_contig_pages overflow

Greg Kroah-Hartman
2019-04-15T19:17:38Z

From: David Rientjes <rientjes@google.com>

commit ede885ecb2cdf8a8dd5367702e3d964ec846a2d5 upstream.

get_num_contig_pages() could potentially overflow int so make its type
consistent with its usage.

Reported-by: Cfir Cohen <cfir@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kvm/svm.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6422,11 +6422,11 @@ e_free:
return ret;
}

-static int get_num_contig_pages(int idx, struct page **inpages,
- unsigned long npages)
+static unsigned long get_num_contig_pages(unsigned long idx,
+ struct page **inpages, unsigned long npages)
{
unsigned long paddr, next_paddr;
- int i = idx + 1, pages = 1;
+ unsigned long i = idx + 1, pages = 1;

/* find the number of contiguous pages starting from idx */
paddr = __sme_page_pa(inpages[idx]);
@@ -6445,12 +6445,12 @@ static int get_num_contig_pages(int idx,

static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
- unsigned long vaddr, vaddr_end, next_vaddr, npages, size;
+ unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
struct kvm_sev_launch_update_data params;
struct sev_data_launch_update_data *data;
struct page **inpages;
- int i, ret, pages;
+ int ret;

if (!sev_guest(kvm))
return -ENOTTY;