[Xen-devel] [PATCH for-4.5 V7 01/14] x86/EFI: fix freeing of uninitialized pointer

[Roy Franz <roy.franz@xxxxxxxxxx>]

The only valid response from the LocateHandle() call is EFI_BUFFER_TOO_SMALL,
so exit if we get anything else.  We pass a 0 size/NULL pointer buffer, so the
only other returns we will get is an error.  Return right away as there is
nothing to do.  Also return if there is an error allocating the buffer, as the
previous code path also allowed for an undefined pointer to be freed.

Signed-off-by: Roy Franz <roy.franz@xxxxxxxxxx>

Re-structure the change.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/efi/boot.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/efi/boot.c b/xen/arch/x86/efi/boot.c
index 3bdc158..6f34592 100644
--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -595,11 +595,12 @@ static void __init setup_efi_pci(void)
     struct efi_pci_rom *last = NULL;
 
     status = efi_bs->LocateHandle(ByProtocol, &pci_guid, NULL, &size, NULL);
-    if ( status == EFI_BUFFER_TOO_SMALL )
-        status = efi_bs->AllocatePool(EfiLoaderData, size, (void **)&handles);
-    if ( !EFI_ERROR(status) )
-        status = efi_bs->LocateHandle(ByProtocol, &pci_guid, NULL, &size,
-                                      handles);
+    if ( status != EFI_BUFFER_TOO_SMALL )
+        return;
+    status = efi_bs->AllocatePool(EfiLoaderData, size, (void **)&handles);
+    if ( EFI_ERROR(status) )
+        return;
+    status = efi_bs->LocateHandle(ByProtocol, &pci_guid, NULL, &size, handles);
     if ( EFI_ERROR(status) )
         size = 0;
 
-- 
2.1.0


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