diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2019-08-12 12:15:17 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-25 10:51:48 +0200 |
| commit | 23a9fc5c5fcd822f8885047ea90cd9a59aef7bc0 (patch) | |
| tree | 02c7e89f000642f385c21b6c355840356ce42b5e /drivers/staging | |
| parent | 3bed38ded6642d01b428ecdd48c972c79fde0e26 (diff) | |
staging: comedi: dt3000: Fix signed integer overflow 'divider * base'
commit b4d98bc3fc93ec3a58459948a2c0e0c9b501cd88 upstream.
In `dt3k_ns_to_timer()` the following lines near the end of the function
result in a signed integer overflow:
prescale = 15;
base = timer_base * (1 << prescale);
divider = 65535;
*nanosec = divider * base;
(`divider`, `base` and `prescale` are type `int`, `timer_base` and
`*nanosec` are type `unsigned int`. The value of `timer_base` will be
either 50 or 100.)
The main reason for the overflow is that the calculation for `base` is
completely wrong. It should be:
base = timer_base * (prescale + 1);
which matches an earlier instance of this calculation in the same
function.
Reported-by: David Binderman <dcb314@hotmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20190812111517.26803-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/comedi/drivers/dt3000.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/staging/comedi/drivers/dt3000.c b/drivers/staging/comedi/drivers/dt3000.c index 19e0b7be8495..6840b1ab620b 100644 --- a/drivers/staging/comedi/drivers/dt3000.c +++ b/drivers/staging/comedi/drivers/dt3000.c @@ -377,7 +377,7 @@ static int dt3k_ns_to_timer(unsigned int timer_base, unsigned int *nanosec, } prescale = 15; - base = timer_base * (1 << prescale); + base = timer_base * (prescale + 1); divider = 65535; *nanosec = divider * base; return (prescale << 16) | (divider); |