[ 47/75] x86, efi: Fix pointer math issue in handle_ramdisks()

Greg KH
2012-05-04T21:10:48Z

From: Dan Carpenter <dan.carpenter@oracle.com>

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>

---
arch/x86/boot/compressed/eboot.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- 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_
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_
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_
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;