2014-07-26 0:52 GMT+04:00 Sasha Levin <sasha.le...@oracle.com>: > On 07/25/2014 11:23 AM, Andrey Ryabinin wrote: >> After this report there was no usual "Unable to handle kernel NULL pointer >> dereference" >> and this gave me a clue that address 0 is mapped and contains valid socket >> address structure in it. > > Interesting. Does it mean that all network protocols that check it for being > NULL instead of checking > the length are incorrect? >
I think they are correct. After verify_iovec() we should have either both msg->msg_name == 0 and msg->msg_namelen == 0, or both != 0 (and msg_name should be a kernel address). That bug allows to leave verify_iovec() with msg_namelen > 0 and msg_name == NULL, causing troubles for protocols checking only msg_namelen. > (such as:) > > if (msg->msg_name) { > DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name); > > [...] > > > Thanks, > Sasha > -- Best regards, Andrey Ryabinin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/