From 8b4017d8c191822f1c93744e7876c9020e6209aa Mon Sep 17 00:00:00 2001 From: Ian Munsie Date: Thu, 11 Mar 2010 12:07:24 +0000 Subject: [PATCH] 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: Ian Munsie Cc: Armin Schindler Cc: Karsten Keil Cc: Stoyan Gaydarov Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- drivers/isdn/hardware/eicon/message.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/isdn/hardware/eicon/message.c b/drivers/isdn/hardware/eicon/message.c index ae89fb89da64..4bd469b0c631 100644 --- a/drivers/isdn/hardware/eicon/message.c +++ b/drivers/isdn/hardware/eicon/message.c @@ -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; -- 2.34.1