On Wed, 2012-10-10 at 12:42 +0300, Dan Carpenter wrote:
> "protos" is an array of unsigned longs and "i" is the number of bits in
> an unsigned long so we need to use 1UL as well to prevent the shift
> from wrapping around.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
> index a1e7601..69b5b58 100644
> --- a/drivers/isdn/i4l/isdn_ppp.c
> +++ b/drivers/isdn/i4l/isdn_ppp.c
> @@ -595,7 +595,7 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
> j = ipc->num / (sizeof(long) * 8);
> i = ipc->num % (sizeof(long) * 8);
> if (j < 8)
> - protos[j] |= (0x1 << i);
> + protos[j] |= (1UL << i);
This looks like a bitmap and probably it should use
DECLARE_BITMAP and set_bit.
Also, it looks like the set_arg size is wrong and is
a stack leak.
Maybe:
drivers/isdn/i4l/isdn_ppp.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index a1e7601..6438d0c 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -471,7 +471,7 @@ int
isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
{
unsigned long val;
- int r, i, j;
+ int r;
struct ippp_struct *is;
isdn_net_local *lp;
struct isdn_ppp_comp_data data;
@@ -589,16 +589,15 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
break;
case PPPIOCGCOMPRESSORS:
{
- unsigned long protos[8] = {0,};
+ DECLARE_BITMAP(protos, BITS_PER_LONG * 8) = { 0, };
struct isdn_ppp_compressor *ipc = ipc_head;
+
while (ipc) {
- j = ipc->num / (sizeof(long) * 8);
- i = ipc->num % (sizeof(long) * 8);
- if (j < 8)
- protos[j] |= (0x1 << i);
+ if (ipc->num < BITS_PER_LONG * 8)
+ set_bit(ipc->num, protos);
ipc = ipc->next;
}
- if ((r = set_arg(argp, protos, 8 * sizeof(long))))
+ if ((r = set_arg(argp, protos, sizeof(protos))))
return r;
}
break;
--
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