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Date: Mon, 17 Aug 2020 12:41:34 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: kernel test robot <lkp@...el.com>
Cc: Jens Axboe <axboe@...nel.dk>, kbuild-all@...ts.01.org,
Christian Brauner <christian.brauner@...ntu.com>,
Jann Horn <jannh@...gle.com>, Jeff Moyer <jmoyer@...hat.com>,
linux-fsdevel@...r.kernel.org, Sargun Dhillon <sargun@...gun.me>,
Kees Cook <keescook@...omium.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Kernel Hardening <kernel-hardening@...ts.openwall.com>,
Stefan Hajnoczi <stefanha@...hat.com>
Subject: Re: [PATCH v4 2/3] io_uring: add IOURING_REGISTER_RESTRICTIONS opcode
On Fri, Aug 14, 2020 at 01:42:15AM +0800, kernel test robot wrote:
> Hi Stefano,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v5.8 next-20200813]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/0day-ci/linux/commits/Stefano-Garzarella/io_uring-add-restrictions-to-support-untrusted-applications-and-guests/20200813-233653
> base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git dc06fe51d26efc100ac74121607c01a454867c91
> config: s390-randconfig-c003-20200813 (attached as .config)
> compiler: s390-linux-gcc (GCC) 9.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@...el.com>
>
>
> coccinelle warnings: (new ones prefixed by >>)
>
> >> fs/io_uring.c:8516:7-14: WARNING opportunity for memdup_user
Yeah, I think make sense.
I'll use memdup_user() in the next version.
>
> vim +8516 fs/io_uring.c
>
> 8497
> 8498 static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
> 8499 unsigned int nr_args)
> 8500 {
> 8501 struct io_uring_restriction *res;
> 8502 size_t size;
> 8503 int i, ret;
> 8504
> 8505 /* We allow only a single restrictions registration */
> 8506 if (ctx->restricted)
> 8507 return -EBUSY;
> 8508
> 8509 if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
> 8510 return -EINVAL;
> 8511
> 8512 size = array_size(nr_args, sizeof(*res));
> 8513 if (size == SIZE_MAX)
> 8514 return -EOVERFLOW;
> 8515
> > 8516 res = kmalloc(size, GFP_KERNEL);
> 8517 if (!res)
> 8518 return -ENOMEM;
> 8519
> 8520 if (copy_from_user(res, arg, size)) {
> 8521 ret = -EFAULT;
> 8522 goto out;
> 8523 }
> 8524
> 8525 for (i = 0; i < nr_args; i++) {
> 8526 switch (res[i].opcode) {
> 8527 case IORING_RESTRICTION_REGISTER_OP:
> 8528 if (res[i].register_op >= IORING_REGISTER_LAST) {
> 8529 ret = -EINVAL;
> 8530 goto out;
> 8531 }
> 8532
> 8533 __set_bit(res[i].register_op,
> 8534 ctx->restrictions.register_op);
> 8535 break;
> 8536 case IORING_RESTRICTION_SQE_OP:
> 8537 if (res[i].sqe_op >= IORING_OP_LAST) {
> 8538 ret = -EINVAL;
> 8539 goto out;
> 8540 }
> 8541
> 8542 __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
> 8543 break;
> 8544 case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
> 8545 ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
> 8546 break;
> 8547 case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
> 8548 ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
> 8549 break;
> 8550 default:
> 8551 ret = -EINVAL;
> 8552 goto out;
> 8553 }
> 8554 }
> 8555
> 8556 ctx->restricted = 1;
> 8557
> 8558 ret = 0;
> 8559 out:
> 8560 /* Reset all restrictions if an error happened */
> 8561 if (ret != 0)
> 8562 memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
> 8563
> 8564 kfree(res);
> 8565 return ret;
> 8566 }
> 8567
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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