isdnloop: several buffer overflows
There are three buffer overflows addressed in this patch. 1) In isdnloop_fake_err() we add an 'E' to a 60 character string and then copy it into a 60 character buffer. I have made the destination buffer 64 characters and I'm changed the sprintf() to a snprintf(). 2) In isdnloop_parse_cmd(), p points to a 6 characters into a 60 character buffer so we have 54 characters. The ->eazlist[] is 11 characters long. I have modified the code to return if the source buffer is too long. 3) In isdnloop_command() the cbuf[] array was 60 characters long but the max length of the string then can be up to 79 characters. I made the cbuf array 80 characters long and changed the sprintf() to snprintf(). I also removed the temporary "dial" buffer and changed it to use "p" directly. Unfortunately, we pass the "cbuf" string from isdnloop_command() to isdnloop_writecmd() which truncates anything over 60 characters to make it fit in card->omsg[]. (It can accept values up to 255 characters so long as there is a '\n' character every 60 characters). For now I have just fixed the memory corruption bug and left the other problems in this driver alone. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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