target/linux/generic/patches-2.6.30/000-bzip_lzma_remove_nasty_hack.patch

   1 From b1af4315d823a2b6659c5b14bc17f7bc61878ef4 Mon Sep 17 00:00:00 2001
   2 From: Phillip Lougher <phillip@lougher.demon.co.uk>
   3 Date: Thu, 6 Aug 2009 15:09:31 -0700
   4 Subject: [PATCH] bzip2/lzma: remove nasty uncompressed size hack in pre-boot environment
   5
   6 decompress_bunzip2 and decompress_unlzma have a nasty hack that subtracts
   7 4 from the input length if being called in the pre-boot environment.
   8
   9 This is a nasty hack because it relies on the fact that flush = NULL only
  10 when called from the pre-boot environment (i.e.
  11 arch/x86/boot/compressed/misc.c).  initramfs.c/do_mounts_rd.c pass in a
  12 flush buffer (flush != NULL).
  13
  14 This hack prevents the decompressors from being used with flush = NULL by
  15 other callers unless knowledge of the hack is propagated to them.
  16
  17 This patch removes the hack by making decompress (called only from the
  18 pre-boot environment) a wrapper function that subtracts 4 from the input
  19 length before calling the decompressor.
  20
  21 Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
  22 Cc: "H. Peter Anvin" <hpa@zytor.com>
  23 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  24 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  25 ---
  26  lib/decompress_bunzip2.c |   22 ++++++++++++++++------
  27  lib/decompress_unlzma.c  |   21 ++++++++++++++++-----
  28  2 files changed, 32 insertions(+), 11 deletions(-)
  29
  30 --- a/lib/decompress_bunzip2.c
  31 +++ b/lib/decompress_bunzip2.c
  32 @@ -45,9 +45,11 @@
  33  */
  34
  35
  36 -#ifndef STATIC
  37 +#ifdef STATIC
  38 +#define PREBOOT
  39 +#else
  40  #include <linux/decompress/bunzip2.h>
  41 -#endif /* !STATIC */
  42 +#endif /* STATIC */
  43
  44  #include <linux/decompress/mm.h>
  45  #include <linux/slab.h>
  46 @@ -681,9 +683,7 @@ STATIC int INIT bunzip2(unsigned char *b
  47         set_error_fn(error_fn);
  48         if (flush)
  49                 outbuf = malloc(BZIP2_IOBUF_SIZE);
  50 -       else
  51 -               len -= 4; /* Uncompressed size hack active in pre-boot
  52 -                            environment */
  53 +
  54         if (!outbuf) {
  55                 error("Could not allocate output bufer");
  56                 return -1;
  57 @@ -733,4 +733,14 @@ exit_0:
  58         return i;
  59  }
  60
  61 -#define decompress bunzip2
  62 +#ifdef PREBOOT
  63 +STATIC int INIT decompress(unsigned char *buf, int len,
  64 +                       int(*fill)(void*, unsigned int),
  65 +                       int(*flush)(void*, unsigned int),
  66 +                       unsigned char *outbuf,
  67 +                       int *pos,
  68 +                       void(*error_fn)(char *x))
  69 +{
  70 +       return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error_fn);
  71 +}
  72 +#endif
  73 --- a/lib/decompress_unlzma.c
  74 +++ b/lib/decompress_unlzma.c
  75 @@ -29,7 +29,9 @@
  76   *Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  77   */
  78
  79 -#ifndef STATIC
  80 +#ifdef STATIC
  81 +#define PREBOOT
  82 +#else
  83  #include <linux/decompress/unlzma.h>
  84  #endif /* STATIC */
  85
  86 @@ -543,9 +545,7 @@ STATIC inline int INIT unlzma(unsigned c
  87         int ret = -1;
  88
  89         set_error_fn(error_fn);
  90 -       if (!flush)
  91 -               in_len -= 4; /* Uncompressed size hack active in pre-boot
  92 -                               environment */
  93 +
  94         if (buf)
  95                 inbuf = buf;
  96         else
  97 @@ -645,4 +645,15 @@ exit_0:
  98         return ret;
  99  }
 100
 101 -#define decompress unlzma
 102 +#ifdef PREBOOT
 103 +STATIC int INIT decompress(unsigned char *buf, int in_len,
 104 +                             int(*fill)(void*, unsigned int),
 105 +                             int(*flush)(void*, unsigned int),
 106 +                             unsigned char *output,
 107 +                             int *posp,
 108 +                             void(*error_fn)(char *x)
 109 +       )
 110 +{
 111 +       return unlzma(buf, in_len - 4, fill, flush, output, posp, error_fn);
 112 +}
 113 +#endif