RDMA/ucma: Fix use-after-free access in ucma_close
The error in ucma_create_id() left ctx in the list of contexts belong
to ucma file descriptor. The attempt to close this file descriptor causes
to use-after-free accesses while iterating over such list.
Fixes: 75216638572f ("RDMA/cma: Export rdma cm interface to userspace")
Reported-by: <syzbot+dcfd344365a56fbebd0f@syzkaller.appspotmail.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 3f3f7bb..14c260e 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -497,6 +497,9 @@ static ssize_t ucma_create_id(struct ucma_file *file, const char __user *inbuf,
mutex_lock(&mut);
idr_remove(&ctx_idr, ctx->id);
mutex_unlock(&mut);
+ mutex_lock(&file->mut);
+ list_del(&ctx->list);
+ mutex_unlock(&file->mut);
kfree(ctx);
return ret;
}