target/linux/brcm63xx/patches-3.7/005-MIPS-BCM63XX-fix-nvram-checksum-calculation.patch

   1 From 7180de9a27ce433efc15bc1982b9a9e4ba3c48dc Mon Sep 17 00:00:00 2001
   2 From: Jonas Gorski <jonas.gorski@gmail.com>
   3 Date: Sat, 10 Nov 2012 02:04:58 +0100
   4 Subject: [PATCH] MIPS: BCM63XX: fix nvram checksum calculation
   5
   6 The current checksum calculation code does nothing except checking that
   7 the first byte of nvram is 0 without actually checking the checksum.
   8
   9 Implement the correct checksum calculation by calculating the crc32 with
  10 the checksum field set to 0.
  11
  12 Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
  13 ---
  14
  15 This patch depends on the previous nvram patch ("move nvram functions
  16 into their own file").
  17
  18  arch/mips/bcm63xx/nvram.c |   23 +++++++++++++----------
  19  1 files changed, 13 insertions(+), 10 deletions(-)
  20
  21 --- a/arch/mips/bcm63xx/nvram.c
  22 +++ b/arch/mips/bcm63xx/nvram.c
  23 @@ -11,6 +11,7 @@
  24  #define pr_fmt(fmt) "bcm63xx_nvram: " fmt
  25
  26  #include <linux/init.h>
  27 +#include <linux/crc32.h>
  28  #include <linux/export.h>
  29  #include <linux/kernel.h>
  30  #include <linux/if_ether.h>
  31 @@ -40,23 +41,25 @@ static int mac_addr_used;
  32  int __init bcm63xx_nvram_init(void *addr)
  33  {
  34         unsigned int check_len;
  35 -       u8 *p;
  36 -       u32 val;
  37 +       u32 crc, expected_crc;
  38
  39         /* extract nvram data */
  40         memcpy(&nvram, addr, sizeof(nvram));
  41
  42         /* check checksum before using data */
  43 -       if (nvram.version <= 4)
  44 -               check_len = offsetof(struct bcm963xx_nvram, checksum_old);
  45 -       else
  46 +       if (nvram.version <= 4) {
  47 +               check_len = offsetof(struct bcm963xx_nvram, reserved3);
  48 +               expected_crc = nvram.checksum_old;
  49 +               nvram.checksum_old = 0;
  50 +       } else {
  51                 check_len = sizeof(nvram);
  52 -       val = 0;
  53 -       p = (u8 *)&nvram;
  54 +               expected_crc = nvram.checksum_high;
  55 +               nvram.checksum_high = 0;
  56 +       }
  57
  58 -       while (check_len--)
  59 -               val += *p;
  60 -       if (val)
  61 +       crc = crc32_le(~0, (u8 *)&nvram, check_len);
  62 +
  63 +       if (crc != expected_crc)
  64                 return -EINVAL;
  65
  66         return 0;