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Commit 8b4017d8 authored by Ian Munsie's avatar Ian Munsie Committed by David S. Miller
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i4l: silence compiler warnings for array access in Eicon DIVA ISDN driver 



When compiling this driver, the compiler throws the following warnings:

drivers/isdn/hardware/eicon/message.c:8426: warning: array subscript is above array bounds
drivers/isdn/hardware/eicon/message.c:8427: warning: array subscript is above array bounds
drivers/isdn/hardware/eicon/message.c:8434: warning: array subscript is above array bounds
drivers/isdn/hardware/eicon/message.c:8435: warning: array subscript is above array bounds
drivers/isdn/hardware/eicon/message.c:8436: warning: array subscript is above array bounds
drivers/isdn/hardware/eicon/message.c:8447: warning: array subscript is above array bounds

This arises from the particular semantics the driver is using to write to
the nlc array (static byte[256]).  The array has a length in byte 0
followed by a T30_INFO struct starting at byte 1.

The T30_INFO struct has a number of variable length strings after the
station_id entry, which cannot be explicitly defined in the struct and the
driver accesses them with an array index to station_id beyond the length
of station_id.

This patch merely changes the semantics that the driver uses to access the
entries after the station_id entry to use the original 256 byte nlc array
taking the offset and length of the station_id entry to calculate where to
write in the array, thereby silencing the warning.

Signed-off-by: default avatarIan Munsie <imunsie@au.ibm.com>
Cc: Armin Schindler <mac@melware.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Stoyan Gaydarov <sgayda2@uiuc.edu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dec9951b

drivers/isdn/hardware/eicon/message.c

+7 −8
Original line number Diff line number Diff line
@@ -8423,17 +8423,17 @@ static word add_b23(PLCI *plci, API_PARSE *bp) 
            pos = 0;

          else

          {

            ((T30_INFO *)&nlc[1])->station_id[20 + pos++] = ' ';

            ((T30_INFO *)&nlc[1])->station_id[20 + pos++] = ' ';

            nlc[1 + offsetof(T30_INFO, station_id) + 20 + pos++] = ' ';

            nlc[1 + offsetof(T30_INFO, station_id) + 20 + pos++] = ' ';

            len = (byte)b3_config_parms[2].length;

            if (len > 20)

              len = 20;

            if (CAPI_MAX_DATE_TIME_LENGTH + 2 + len + 2 + b3_config_parms[3].length <= CAPI_MAX_HEAD_LINE_SPACE)

            {

              for (i = 0; i < len; i++)

                ((T30_INFO *)&nlc[1])->station_id[20 + pos++] = ((byte   *)b3_config_parms[2].info)[1+i];

              ((T30_INFO *)&nlc[1])->station_id[20 + pos++] = ' ';

              ((T30_INFO *)&nlc[1])->station_id[20 + pos++] = ' ';

                nlc[1 + offsetof(T30_INFO, station_id) + 20 + pos++] = ((byte   *)b3_config_parms[2].info)[1+i];

              nlc[1 + offsetof(T30_INFO, station_id) + 20 + pos++] = ' ';

              nlc[1 + offsetof(T30_INFO, station_id) + 20 + pos++] = ' ';

            }

          }

        }
@@ -8444,9 +8444,8 @@ static word add_b23(PLCI *plci, API_PARSE *bp) 
        ((T30_INFO *)&nlc[1])->head_line_len = (byte)(pos + len);

        nlc[0] += (byte)(pos + len);

        for (i = 0; i < len; i++)

          ((T30_INFO *)&nlc[1])->station_id[20 + pos++] = ((byte   *)b3_config_parms[3].info)[1+i];

        }

      else

          nlc[1 + offsetof(T30_INFO, station_id) + 20 + pos++] =  ((byte   *)b3_config_parms[3].info)[1+i];

      } else

        ((T30_INFO *)&nlc[1])->head_line_len = 0;



      plci->nsf_control_bits = 0;