s390/sclp: always stay within bounds of the early sccb

Make sure the _sclp_print_lm function stays within bounds of the early
sccb, even if the passed string is very long.  If the string is too
long, the remaining characters will be dropped.

Suggested-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2017-01-11 11:07:39 +01:00 committed by Martin Schwidefsky
parent 742dc5773c
commit f031974859

View File

@ -132,16 +132,21 @@ static void _sclp_print_lm(const char *str)
0x10, 0x00, /* 4 */
0x00, 0x00, 0x00, 0x00 /* 6 */
};
unsigned char *ptr, ch;
unsigned char *ptr, *end_ptr, ch;
unsigned int count;
memcpy(_sclp_work_area, write_head, sizeof(write_head));
ptr = _sclp_work_area + sizeof(write_head);
end_ptr = _sclp_work_area + sizeof(_sclp_work_area) - 1;
do {
if (ptr + sizeof(write_mto) > end_ptr)
break;
memcpy(ptr, write_mto, sizeof(write_mto));
for (count = sizeof(write_mto); (ch = *str++) != 0; count++) {
if (ch == 0x0a)
break;
if (ptr > end_ptr)
break;
ptr[count] = _ascebc[ch];
}
/* Update length fields in mto, mdb, evbuf and sccb */