Re: [PATCH v4 2/3] io_uring: add IOURING_REGISTER_RESTRICTIONS opcode

From: kernel test robot <lkp@intel.com>
To: Stefano Garzarella <sgarzare@redhat.com>, Jens Axboe <axboe@kernel.dk>
Cc: kbuild-all@lists.01.org,
	Christian Brauner <christian.brauner@ubuntu.com>,
	Jann Horn <jannh@google.com>, Jeff Moyer <jmoyer@redhat.com>,
	linux-fsdevel@vger.kernel.org, Sargun Dhillon <sargun@sargun.me>,
	Kees Cook <keescook@chromium.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [PATCH v4 2/3] io_uring: add IOURING_REGISTER_RESTRICTIONS opcode
Date: Fri, 14 Aug 2020 01:42:15 +0800	[thread overview]
Message-ID: <202008140142.UYrgnsNY%lkp@intel.com> (raw)
In-Reply-To: <20200813153254.93731-3-sgarzare@redhat.com>

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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@intel.com>

coccinelle warnings: (new ones prefixed by >>)

>> fs/io_uring.c:8516:7-14: WARNING opportunity for memdup_user

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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