Messages in this thread | | | Subject | Re: [PATCH] ipv4: fib: avoid NULL dereference | From | Eric Dumazet <> | Date | Fri, 6 Jul 2018 08:39:11 -0700 |
| |
On 07/06/2018 07:57 AM, Mark Rutland wrote: > On Fri, Jul 06, 2018 at 07:47:04AM -0700, Eric Dumazet wrote: >> >> >> On 07/06/2018 07:28 AM, Mark Rutland wrote: >>> In tnode_free() we iterate over a callback_head list with a while loop. >>> At the start of the loop body we generate the next head pointer, and at >>> the end of the loop body we generate the tn pointer for the next >>> iteration of the loop by using container_of() on the head pointer to >>> find the tnode, and deriving the kv pointer from this. >>> >>> In the final iteration of the loop, this means that we derive a pointer >>> from NULL, which is undefined behaviour, which UBSAN detects: >> >> There is no dereference, your patch title is misleading. >> >> UBSAN might be fooled, not the C compiler. > > I'm happy to change the title to "avoid undefined behaviour". >
Are you planning to change this as well ?
include/linux/stddef.h:19:#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
(And probably dozens of other locations)
| |