queue-5.1/tipc-avoid-copying-bytes-beyond-the-supplied-data.patch

   1 From foo@baz Fri 31 May 2019 03:16:39 PM PDT
   2 From: Chris Packham <chris.packham@alliedtelesis.co.nz>
   3 Date: Mon, 20 May 2019 15:45:36 +1200
   4 Subject: tipc: Avoid copying bytes beyond the supplied data
   5
   6 From: Chris Packham <chris.packham@alliedtelesis.co.nz>
   7
   8 TLV_SET is called with a data pointer and a len parameter that tells us
   9 how many bytes are pointed to by data. When invoking memcpy() we need
  10 to careful to only copy len bytes.
  11
  12 Previously we would copy TLV_LENGTH(len) bytes which would copy an extra
  13 4 bytes past the end of the data pointer which newer GCC versions
  14 complain about.
  15
  16  In file included from test.c:17:
  17  In function 'TLV_SET',
  18      inlined from 'test' at test.c:186:5:
  19  /usr/include/linux/tipc_config.h:317:3:
  20  warning: 'memcpy' forming offset [33, 36] is out of the bounds [0, 32]
  21  of object 'bearer_name' with type 'char[32]' [-Warray-bounds]
  22      memcpy(TLV_DATA(tlv_ptr), data, tlv_len);
  23      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  24  test.c: In function 'test':
  25  test.c::161:10: note:
  26  'bearer_name' declared here
  27      char bearer_name[TIPC_MAX_BEARER_NAME];
  28           ^~~~~~~~~~~
  29
  30 We still want to ensure any padding bytes at the end are initialised, do
  31 this with a explicit memset() rather than copy bytes past the end of
  32 data. Apply the same logic to TCM_SET.
  33
  34 Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
  35 Signed-off-by: David S. Miller <davem@davemloft.net>
  36 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  37 ---
  38  include/uapi/linux/tipc_config.h |   10 +++++++---
  39  1 file changed, 7 insertions(+), 3 deletions(-)
  40
  41 --- a/include/uapi/linux/tipc_config.h
  42 +++ b/include/uapi/linux/tipc_config.h
  43 @@ -307,8 +307,10 @@ static inline int TLV_SET(void *tlv, __u
  44         tlv_ptr = (struct tlv_desc *)tlv;
  45         tlv_ptr->tlv_type = htons(type);
  46         tlv_ptr->tlv_len  = htons(tlv_len);
  47 -       if (len && data)
  48 -               memcpy(TLV_DATA(tlv_ptr), data, tlv_len);
  49 +       if (len && data) {
  50 +               memcpy(TLV_DATA(tlv_ptr), data, len);
  51 +               memset(TLV_DATA(tlv_ptr) + len, 0, TLV_SPACE(len) - tlv_len);
  52 +       }
  53         return TLV_SPACE(len);
  54  }
  55
  56 @@ -405,8 +407,10 @@ static inline int TCM_SET(void *msg, __u
  57         tcm_hdr->tcm_len   = htonl(msg_len);
  58         tcm_hdr->tcm_type  = htons(cmd);
  59         tcm_hdr->tcm_flags = htons(flags);
  60 -       if (data_len && data)
  61 +       if (data_len && data) {
  62                 memcpy(TCM_DATA(msg), data, data_len);
  63 +               memset(TCM_DATA(msg) + data_len, 0, TCM_SPACE(data_len) - msg_len);
  64 +       }
  65         return TCM_SPACE(data_len);
  66  }
  67