diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2018-09-12 16:27:44 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-13 09:11:34 +0200 |
| commit | 38ea605f919c61fc0c3ca65abeaa87ca83f2110e (patch) | |
| tree | 8c547a6aa75e158be60e5b432a37b3720aec48c0 | |
| parent | b4dd80c33338df403868222045d6427295ff54e5 (diff) | |
ucma: fix a use-after-free in ucma_resolve_ip()
commit 5fe23f262e0548ca7f19fb79f89059a60d087d22 upstream.
There is a race condition between ucma_close() and ucma_resolve_ip():
CPU0 CPU1
ucma_resolve_ip(): ucma_close():
ctx = ucma_get_ctx(file, cmd.id);
list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) {
mutex_lock(&mut);
idr_remove(&ctx_idr, ctx->id);
mutex_unlock(&mut);
...
mutex_lock(&mut);
if (!ctx->closing) {
mutex_unlock(&mut);
rdma_destroy_id(ctx->cm_id);
...
ucma_free_ctx(ctx);
ret = rdma_resolve_addr();
ucma_put_ctx(ctx);
Before idr_remove(), ucma_get_ctx() could still find the ctx
and after rdma_destroy_id(), rdma_resolve_addr() may still
access id_priv pointer. Also, ucma_put_ctx() may use ctx after
ucma_free_ctx() too.
ucma_close() should call ucma_put_ctx() too which tests the
refcnt and waits for the last one releasing it. The similar
pattern is already used by ucma_destroy_id().
Reported-and-tested-by: syzbot+da2591e115d57a9cbb8b@syzkaller.appspotmail.com
Reported-by: syzbot+cfe3c1e8ef634ba8964b@syzkaller.appspotmail.com
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/infiniband/core/ucma.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c index 9712a63957e1..7525e9f6949e 100644 --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -1709,6 +1709,8 @@ static int ucma_close(struct inode *inode, struct file *filp) mutex_lock(&mut); if (!ctx->closing) { mutex_unlock(&mut); + ucma_put_ctx(ctx); + wait_for_completion(&ctx->comp); /* rdma_destroy_id ensures that no event handlers are * inflight for that id before releasing it. */ |