io_uring/af_unix: disable sending io_uring over sockets

File reference cycles have caused lots of problems for io_uring
in the past, and it still doesn't work exactly right and races with
unix_stream_read_generic(). The safest fix would be to completely
disallow sending io_uring files via sockets via SCM_RIGHT, so there
are no possible cycles invloving registered files and thus rendering
SCM accounting on the io_uring side unnecessary.

Cc: stable@vger.kernel.org
Fixes: 0091bfc817 ("io_uring/af_unix: defer registered files gc to io_uring release")
Reported-and-suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pavel Begunkov 2023-12-06 13:55:19 +00:00 committed by David S. Miller
parent 15319a4e8e
commit 69db702c83
2 changed files with 6 additions and 7 deletions

View File

@ -77,17 +77,10 @@ int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file);
#if defined(CONFIG_UNIX)
static inline bool io_file_need_scm(struct file *filp)
{
return !!unix_get_socket(filp);
}
#else
static inline bool io_file_need_scm(struct file *filp)
{
return false;
}
#endif
static inline int io_scm_file_account(struct io_ring_ctx *ctx,
struct file *file)

View File

@ -26,6 +26,7 @@
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/errqueue.h>
#include <linux/io_uring.h>
#include <linux/uaccess.h>
@ -103,6 +104,11 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
if (fd < 0 || !(file = fget_raw(fd)))
return -EBADF;
/* don't allow io_uring files */
if (io_uring_get_socket(file)) {
fput(file);
return -EINVAL;
}
*fpp++ = file;
fpl->count++;
}