releases/4.19.33/kbuild-modversions-fix-relative-crc-byte-order-interpretation.patch

   1 From 54a7151b1496cddbb7a83546b7998103e98edc88 Mon Sep 17 00:00:00 2001
   2 From: Fredrik Noring <noring@nocrew.org>
   3 Date: Wed, 27 Mar 2019 19:12:50 +0100
   4 Subject: kbuild: modversions: Fix relative CRC byte order interpretation
   5
   6 From: Fredrik Noring <noring@nocrew.org>
   7
   8 commit 54a7151b1496cddbb7a83546b7998103e98edc88 upstream.
   9
  10 Fix commit 56067812d5b0 ("kbuild: modversions: add infrastructure for
  11 emitting relative CRCs") where CRCs are interpreted in host byte order
  12 rather than proper kernel byte order. The bug is conditional on
  13 CONFIG_MODULE_REL_CRCS.
  14
  15 For example, when loading a BE module into a BE kernel compiled with a LE
  16 system, the error "disagrees about version of symbol module_layout" is
  17 produced. A message such as "Found checksum D7FA6856 vs module 5668FAD7"
  18 will be given with debug enabled, which indicates an obvious endian
  19 problem within __kcrctab within the kernel image.
  20
  21 The general solution is to use the macro TO_NATIVE, as is done in
  22 similar cases throughout modpost.c. With this correction it has been
  23 verified that a BE kernel compiled with a LE system accepts BE modules.
  24
  25 This change has also been verified with a LE kernel compiled with a LE
  26 system, in which case TO_NATIVE returns its value unmodified since the
  27 byte orders match. This is by far the common case.
  28
  29 Fixes: 56067812d5b0 ("kbuild: modversions: add infrastructure for emitting relative CRCs")
  30 Signed-off-by: Fredrik Noring <noring@nocrew.org>
  31 Cc: stable@vger.kernel.org
  32 Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
  33 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  34
  35 ---
  36  scripts/mod/modpost.c |    2 +-
  37  1 file changed, 1 insertion(+), 1 deletion(-)
  38
  39 --- a/scripts/mod/modpost.c
  40 +++ b/scripts/mod/modpost.c
  41 @@ -640,7 +640,7 @@ static void handle_modversions(struct mo
  42                                info->sechdrs[sym->st_shndx].sh_offset -
  43                                (info->hdr->e_type != ET_REL ?
  44                                 info->sechdrs[sym->st_shndx].sh_addr : 0);
  45 -                       crc = *crcp;
  46 +                       crc = TO_NATIVE(*crcp);
  47                 }
  48                 sym_update_crc(symname + strlen("__crc_"), mod, crc,
  49                                 export);