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SubjectRe: usercopy whitelist woe in scsi_sense_cache
On Tue, Apr 17, 2018 at 1:46 PM, Kees Cook <keescook@chromium.org> wrote:
> I see elv.priv[1] assignments made in a few places -- is it possible
> there is some kind of uninitialized-but-not-NULL state that can leak
> in there?

Got it. This fixes it for me:

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0dc9e341c2a7..859df3160303 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -363,7 +363,7 @@ static struct request *blk_mq_get_request(struct
request_queue *q,

rq = blk_mq_rq_ctx_init(data, tag, op);
if (!op_is_flush(op)) {
- rq->elv.icq = NULL;
+ memset(&rq->elv, 0, sizeof(rq->elv));
if (e && e->type->ops.mq.prepare_request) {
if (e->type->icq_cache && rq_ioc(bio))
blk_mq_sched_assign_ioc(rq, bio);
@@ -461,7 +461,7 @@ void blk_mq_free_request(struct request *rq)
e->type->ops.mq.finish_request(rq);
if (rq->elv.icq) {
put_io_context(rq->elv.icq->ioc);
- rq->elv.icq = NULL;
+ memset(&rq->elv, 0, sizeof(rq->elv));
}
}


--
Kees Cook
Pixel Security

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