Re: [PATCH] pidfd: add ioctl to retrieve pid info

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

Hi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on shuah-kselftest/next]
[also build test WARNING on shuah-kselftest/fixes linus/master v6.12-rc1 next-20241003]
[cannot apply to brauner-vfs/vfs.all]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/luca-boccassi-gmail-com/pidfd-add-ioctl-to-retrieve-pid-info/20241002-223302
base:   https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git next
patch link:    https://lore.kernel.org/r/20241002142516.110567-1-luca.boccassi%40gmail.com
patch subject: [PATCH] pidfd: add ioctl to retrieve pid info
config: x86_64-randconfig-123-20241004 (https://download.01.org/0day-ci/archive/20241004/202410041128.tLVDbeJB-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241004/202410041128.tLVDbeJB-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/202410041128.tLVDbeJB-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> fs/pidfs.c:121:37: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected void const [noderef] __user *from @@     got struct pidfd_info * @@
   fs/pidfs.c:121:37: sparse:     expected void const [noderef] __user *from
   fs/pidfs.c:121:37: sparse:     got struct pidfd_info *

vim +121 fs/pidfs.c

   116	
   117	static long pidfd_info(struct task_struct *task, struct pid *pid, unsigned long arg)
   118	{
   119		struct pidfd_info uinfo = {}, info = {};
   120	
 > 121		if (copy_from_user(&uinfo, (struct pidfd_info *)arg, sizeof(struct pidfd_info)))
   122			return -EFAULT;
   123		if (uinfo.size > sizeof(struct pidfd_info))
   124			return -E2BIG;
   125		if (uinfo.size < sizeof(struct pidfd_info))
   126			return -EINVAL; /* First version, no smaller struct possible */
   127	
   128		if (uinfo.request_mask & ~(PIDFD_INFO_PID | PIDFD_INFO_CREDS | PIDFD_INFO_CGROUPID | PIDFD_INFO_SECURITY_CONTEXT))
   129			return -EINVAL;
   130	
   131		memcpy(&info, &uinfo, uinfo.size);
   132	
   133		if (uinfo.request_mask & PIDFD_INFO_PID)
   134			info.pid = pid_nr_ns(pid, task_active_pid_ns(task));
   135	
   136		if (uinfo.request_mask & PIDFD_INFO_CREDS) {
   137			const struct cred *c = get_task_cred(task);
   138			if (!c)
   139				return -ESRCH;
   140	
   141			info.uid = from_kuid_munged(current_user_ns(), c->uid);
   142			info.gid = from_kgid_munged(current_user_ns(), c->gid);
   143		}
   144	
   145		if (uinfo.request_mask & PIDFD_INFO_CGROUPID) {
   146			struct cgroup *cgrp = task_css_check(task, pids_cgrp_id, 1)->cgroup;
   147			if (!cgrp)
   148				return -ENODEV;
   149	
   150			info.cgroupid = cgroup_id(cgrp);
   151		}
   152	
   153		if (uinfo.request_mask & PIDFD_INFO_SECURITY_CONTEXT) {
   154			char *secctx;
   155			u32 secid, secctx_len;
   156			const struct cred *c = get_task_cred(task);
   157			if (!c)
   158				return -ESRCH;
   159	
   160			security_cred_getsecid(c, &secid);
   161			if (security_secid_to_secctx(secid, &secctx, &secctx_len))
   162				return -EFAULT;
   163	
   164			memcpy(info.security_context, secctx, min_t(u32, secctx_len, NAME_MAX-1));
   165		}
   166	
   167		if (copy_to_user((void __user *)arg, &info, uinfo.size))
   168			return -EFAULT;
   169	
   170		return 0;
   171	}
   172	

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