staging/bcm: integer underflow leads to Oom

We do:

        if (NOB > DEFAULT_BUFF_SIZE)
                BuffSize = DEFAULT_BUFF_SIZE;
        else
                BuffSize = NOB;

Since NOB can be negative it results in a larger than intended BuffSize
and makes kzalloc() fail.

The code is still a bit crap because it lets the users read as much as
they want from nvram, but I don't know what a sensible upper limit
should be.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
index 6f1997d..5e4dfe0 100644 (file)
--- a/drivers/staging/bcm/Bcmchar.c
+++ b/drivers/staging/bcm/Bcmchar.c
@@ -1894,7 +1894,7 @@ static int bcm_char_ioctl_nvm_raw_read(void __user *argp, struct bcm_mini_adapte
 {
        struct bcm_nvm_readwrite stNVMRead;
        struct bcm_ioctl_buffer IoBuffer;
-       INT NOB;
+       unsigned int NOB;
        INT BuffSize;
        INT ReadOffset = 0;
        UINT ReadBytes = 0;