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author | Ian Abbott <abbotti@mev.co.uk> | 2019-08-12 12:15:17 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-12 16:46:07 +0200 |
commit | b4d98bc3fc93ec3a58459948a2c0e0c9b501cd88 (patch) | |
tree | 1c36825742177089209c1e67f439df3ec37d24bb /drivers/staging | |
parent | d45331b00ddb179e291766617259261c112db872 (diff) | |
download | linux-b4d98bc3fc93ec3a58459948a2c0e0c9b501cd88.tar.gz linux-b4d98bc3fc93ec3a58459948a2c0e0c9b501cd88.tar.bz2 linux-b4d98bc3fc93ec3a58459948a2c0e0c9b501cd88.zip |
staging: comedi: dt3000: Fix signed integer overflow 'divider * base'
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 2edf3ee91300..4ad176fc14ad 100644 --- a/drivers/staging/comedi/drivers/dt3000.c +++ b/drivers/staging/comedi/drivers/dt3000.c @@ -368,7 +368,7 @@ 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); |