A previous change enabled external users to copy the data before calling __get_compat_msghdr(), but didn't modify get_compat_msghdr() or __io_compat_recvmsg_copy_hdr() to take that into account. They are both stil passing in the __user pointer rather than the copied version. Ensure we pass in the kernel struct, not the pointer to the user data. Link: https://lore.kernel.org/all/46439555-644d-08a1-7d66-16f8f9a320f0@xxxxxxxxxxx/ Fixes: 1a3e4e94a1b9 ("net: copy from user before calling __get_compat_msghdr") Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> --- As this was staged in the io_uring tree, I plan on applying this fix there as well. Holler if anyone disagrees. diff --git a/io_uring/net.c b/io_uring/net.c index 6b7d5f33e642..e61efa31c729 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -398,7 +398,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req, if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg))) return -EFAULT; - ret = __get_compat_msghdr(&iomsg->msg, sr->umsg_compat, &iomsg->uaddr); + ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr); if (ret) return ret; diff --git a/net/compat.c b/net/compat.c index 513aa9a3fc64..ed880729d159 100644 --- a/net/compat.c +++ b/net/compat.c @@ -89,7 +89,7 @@ int get_compat_msghdr(struct msghdr *kmsg, if (copy_from_user(&msg, umsg, sizeof(*umsg))) return -EFAULT; - err = __get_compat_msghdr(kmsg, umsg, save_addr); + err = __get_compat_msghdr(kmsg, &msg, save_addr); if (err) return err; -- Jens Axboe
