isdn/capi: prevent index overrun from command_2_index()

The result of the function command_2_index() is used to index two
arrays mnames[] and cpars[] with max. index 0x4e but in its current
form that function can produce results up to 3*(0x9+0x9)+0x7f =
0xb5.
Fix by clamping all result values potentially overrunning the arrays
to zero which is already handled as an invalid value.

Re-spotted with Coverity.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tilman Schmidt 2014-10-11 13:46:30 +02:00 committed by David S. Miller
parent 9ea8aa8d50
commit 5362247a42
1 changed files with 2 additions and 0 deletions

View File

@ -207,6 +207,8 @@ static unsigned command_2_index(unsigned c, unsigned sc)
c = 0x9 + (c & 0x0f);
else if (c == 0x41)
c = 0x9 + 0x1;
if (c > 0x18)
c = 0x00;
return (sc & 3) * (0x9 + 0x9) + c;
}