[Xen-changelog] [xen stable-4.4] x86/EFI: fix freeing of uninitialized pointer

[patchbot@xxxxxxx]

commit 41997d3666baeea34e965c4975d33e7e79d1782d
Author:     Roy Franz <roy.franz@xxxxxxxxxx>
AuthorDate: Fri Oct 17 15:53:46 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Oct 17 15:53:46 2014 +0200

    x86/EFI: fix freeing of uninitialized pointer
    
    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>
    master commit: c61690fb76f9a51a8c932d76929b67bd0940febe
    master date: 2014-09-24 11:09:11 +0200
---
 xen/arch/x86/efi/boot.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/efi/boot.c b/xen/arch/x86/efi/boot.c
index 0dd935c..7044892 100644
--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -594,11 +594,12 @@ 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;
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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