smatch stuff: potential read past the end of the buffer

[Dan Carpenter <error27@gmail.com>]

Hello Vasanthakumar,

Smatch complains that in linux-next 60e0c3a7 "ath9k_hw: Eeeprom changes
for AR9485" means there is a potential read past the end of the buffer
int ar9300_eeprom_restore_internal().

drivers/net/wireless/ath/ath9k/ar9003_eeprom.c +3381
	ar9300_eeprom_restore_internal(81)
	error: buffer overflow 'word' 2048 <= 4099

"word" is allocated with 2048 bytes:
        word = kzalloc(2048, GFP_KERNEL);

"length" can be up to 4099:
                if ((!AR_SREV_9485(ah) && length >= 1024) ||
                    (AR_SREV_9485(ah) && length >= (4 * 1024))) {
                                         ^^^^^^^^^^^^^^^^^^^^^

so "osize" can be up to 4099 as well:
                osize = length;

We're reading way past the end of the word array here:
                mchecksum = word[COMP_HDR_LEN + osize] |
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^
                    (word[COMP_HDR_LEN + osize + 1] << 8);

I don't know how to fix this.  Can you take a look?

regards,
dan carpenter