Re: [PATCH bpf-next v7 2/9] bpf: Propagate modified uaddrlen from cgroup sockaddr programs

[kernel test robot <lkp@intel.com>]

Hi Daan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Daan-De-Meyer/selftests-bpf-Add-missing-section-name-tests-for-getpeername-getsockname/20231002-203646
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20231002122756.323591-3-daan.j.demeyer%40gmail.com
patch subject: [PATCH bpf-next v7 2/9] bpf: Propagate modified uaddrlen from cgroup sockaddr programs
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231002/202310022113.1H3kTKXX-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231002/202310022113.1H3kTKXX-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310022113.1H3kTKXX-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/bpf/cgroup.c:1454: warning: bad line:               read-only for AF_INET[6] uaddr but can be modified for AF_UNIX
>> kernel/bpf/cgroup.c:1455: warning: bad line:               uaddr.


vim +1454 kernel/bpf/cgroup.c

  1447	
  1448	/**
  1449	 * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and
  1450	 *                                       provided by user sockaddr
  1451	 * @sk: sock struct that will use sockaddr
  1452	 * @uaddr: sockaddr struct provided by user
  1453	 * @uaddrlen: Pointer to the size of the sockaddr struct provided by user. It is
> 1454		      read-only for AF_INET[6] uaddr but can be modified for AF_UNIX
> 1455		      uaddr.
  1456	 * @atype: The type of program to be executed
  1457	 * @t_ctx: Pointer to attach type specific context
  1458	 * @flags: Pointer to u32 which contains higher bits of BPF program
  1459	 *         return value (OR'ed together).
  1460	 *
  1461	 * socket is expected to be of type INET or INET6.
  1462	 *
  1463	 * This function will return %-EPERM if an attached program is found and
  1464	 * returned value != 1 during execution. In all other cases, 0 is returned.
  1465	 */
  1466	int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
  1467					      struct sockaddr *uaddr,
  1468					      int *uaddrlen,
  1469					      enum cgroup_bpf_attach_type atype,
  1470					      void *t_ctx,
  1471					      u32 *flags)
  1472	{
  1473		struct bpf_sock_addr_kern ctx = {
  1474			.sk = sk,
  1475			.uaddr = uaddr,
  1476			.t_ctx = t_ctx,
  1477		};
  1478		struct sockaddr_storage unspec;
  1479		struct cgroup *cgrp;
  1480		int ret;
  1481	
  1482		/* Check socket family since not all sockets represent network
  1483		 * endpoint (e.g. AF_UNIX).
  1484		 */
  1485		if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
  1486			return 0;
  1487	
  1488		if (!ctx.uaddr) {
  1489			memset(&unspec, 0, sizeof(unspec));
  1490			ctx.uaddr = (struct sockaddr *)&unspec;
  1491			ctx.uaddrlen = 0;
  1492		} else if (uaddrlen)
  1493			ctx.uaddrlen = *uaddrlen;
  1494		else
  1495			return -EINVAL;
  1496	
  1497		cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
  1498		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run,
  1499					    0, flags);
  1500	
  1501		if (!ret && uaddrlen)
  1502			*uaddrlen = ctx.uaddrlen;
  1503	
  1504		return ret;
  1505	}
  1506	EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);
  1507	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki