x86, efi: Fix pointer math issue in handle_ramdisks()

commit c7b738351ba92f48b943ac59aff6b5b0f17f37c9 upstream.

"filename" is a efi_char16_t string so this check for reaching the end
of the array doesn't work.  We need to cast the pointer to (u8 *) before
doing the math.

This patch changes the "filename" to "filename_16" to avoid confusion in
the future.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20120305180614.GA26880@elgon.mountain
Acked-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index fec216f4fbc3854f11e6253607511c000b995134..0cdfc0d2315e51d84c0c0383bbd3b82020b52ceb 100644 (file)
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -539,7 +539,7 @@ static efi_status_t handle_ramdisks(efi_loaded_image_t *image,
                struct initrd *initrd;
                efi_file_handle_t *h;
                efi_file_info_t *info;
-               efi_char16_t filename[256];
+               efi_char16_t filename_16[256];
                unsigned long info_sz;
                efi_guid_t info_guid = EFI_FILE_INFO_ID;
                efi_char16_t *p;
@@ -552,14 +552,14 @@ static efi_status_t handle_ramdisks(efi_loaded_image_t *image,
                str += 7;
 
                initrd = &initrds[i];
-               p = filename;
+               p = filename_16;
 
                /* Skip any leading slashes */
                while (*str == '/' || *str == '\\')
                        str++;
 
                while (*str && *str != ' ' && *str != '\n') {
-                       if (p >= filename + sizeof(filename))
+                       if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
                                break;
 
                        *p++ = *str++;
@@ -583,7 +583,7 @@ static efi_status_t handle_ramdisks(efi_loaded_image_t *image,
                                goto free_initrds;
                }
 
-               status = efi_call_phys5(fh->open, fh, &h, filename,
+               status = efi_call_phys5(fh->open, fh, &h, filename_16,
                                        EFI_FILE_MODE_READ, (u64)0);
                if (status != EFI_SUCCESS)
                        goto close_handles;