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Date:   Fri, 19 Aug 2022 17:45:36 -0400
From:   Richard Guy Briggs <rgb@redhat.com>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     kernel test robot <lkp@intel.com>,
        Linux-Audit Mailing List <linux-audit@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org, llvm@lists.linux.dev,
        kbuild-all@lists.01.org, Paul Moore <paul@paul-moore.com>,
        Eric Paris <eparis@parisplace.org>,
        Steve Grubb <sgrubb@redhat.com>, Jan Kara <jack@suse.cz>,
        Amir Goldstein <amir73il@gmail.com>
Subject: Re: [PATCH v4 2/4] fanotify: define struct members to hold response
 decision context
Message-ID: <YwAEgFwOm13JPbaE@madcap2.tricolour.ca>
References: <8767f3a0d43d6a994584b86c03eb659a662cc416.1659996830.git.rgb@redhat.com>
 <202208102231.qSUdYAdb-lkp@intel.com>
 <Yv+5ZkFxhR+JK/Rj@madcap2.tricolour.ca>
 <CAKwvOdnQiC++rhVCFToE6t-ZO_VgkhtbH0gy=dEg662EfWucBg@mail.gmail.com>
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On 2022-08-19 10:17, Nick Desaulniers wrote:
> On Fri, Aug 19, 2022 at 9:25 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> >
> > On 2022-08-10 22:28, kernel test robot wrote:
> > > Hi Richard,
> > >
> > > Thank you for the patch! Perhaps something to improve:
> > >
> > > [auto build test WARNING on jack-fs/fsnotify]
> > > [also build test WARNING on pcmoore-audit/next linus/master v5.19 next-20220810]
> > > [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/Richard-Guy-Briggs/fanotify-Allow-user-space-to-pass-back-additional-audit-info/20220810-012825
> > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git fsnotify
> > > config: i386-randconfig-a013 (https://download.01.org/0day-ci/archive/20220810/202208102231.qSUdYAdb-lkp@intel.com/config)
> > > compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 5f1c7e2cc5a3c07cbc2412e851a7283c1841f520)
> > > reproduce (this is a W=1 build):
> > >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > >         chmod +x ~/bin/make.cross
> > >         # https://github.com/intel-lab-lkp/linux/commit/a943676abc023c094f05b45f4d61936c567507a2
> > >         git remote add linux-review https://github.com/intel-lab-lkp/linux
> > >         git fetch --no-tags linux-review Richard-Guy-Briggs/fanotify-Allow-user-space-to-pass-back-additional-audit-info/20220810-012825
> > >         git checkout a943676abc023c094f05b45f4d61936c567507a2
> > >         # save the config file
> > >         mkdir build_dir && cp config build_dir/.config
> > >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash fs/notify/fanotify/
> > >
> > > If you fix the issue, kindly add following tag where applicable
> > > Reported-by: kernel test robot <lkp@intel.com>
> > >
> > > All warnings (new ones prefixed by >>):
> > >
> > > >> fs/notify/fanotify/fanotify_user.c:325:35: warning: format specifies type 'unsigned long' but the argument has type 'size_t' (aka 'unsigned int') [-Wformat]
> >
> > Interesting.  When I "fix" it, my compiler complains:
> >
> >         fs/notify/fanotify/fanotify_user.c:324:11: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 8 has type ‘size_t’ {aka ‘long unsigned int’} [-Wformat=]
> 
> The correct format specifier for size_t is %zu.  This avoids issues
> between ILP32 vs LP64 targets.

Perfect, thanks!

> > >                     group, fd, response, info_buf, count);
> > >                                                    ^~~~~
> > >    include/linux/printk.h:594:38: note: expanded from macro 'pr_debug'
> > >            no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
> > >                                        ~~~     ^~~~~~~~~~~
> > >    include/linux/printk.h:131:17: note: expanded from macro 'no_printk'
> > >                    printk(fmt, ##__VA_ARGS__);             \
> > >                           ~~~    ^~~~~~~~~~~
> > >    include/linux/printk.h:464:60: note: expanded from macro 'printk'
> > >    #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
> > >                                                        ~~~    ^~~~~~~~~~~
> > >    include/linux/printk.h:436:19: note: expanded from macro 'printk_index_wrap'
> > >                    _p_func(_fmt, ##__VA_ARGS__);                           \
> > >                            ~~~~    ^~~~~~~~~~~
> > >    1 warning generated.
> > >
> > >
> > > vim +325 fs/notify/fanotify/fanotify_user.c
> > >
> > >    312
> > >    313        static int process_access_response(struct fsnotify_group *group,
> > >    314                                           struct fanotify_response *response_struct,
> > >    315                                           const char __user *buf,
> > >    316                                           size_t count)
> > >    317        {
> > >    318                struct fanotify_perm_event *event;
> > >    319                int fd = response_struct->fd;
> > >    320                u32 response = response_struct->response;
> > >    321                struct fanotify_response_info_header info_hdr;
> > >    322                char *info_buf = NULL;
> > >    323
> > >    324                pr_debug("%s: group=%p fd=%d response=%u buf=%p size=%lu\n", __func__,
> > >  > 325                         group, fd, response, info_buf, count);
> > >    326                /*
> > >    327                 * make sure the response is valid, if invalid we do nothing and either
> > >    328                 * userspace can send a valid response or we will clean it up after the
> > >    329                 * timeout
> > >    330                 */
> > >    331                if (response & ~FANOTIFY_RESPONSE_VALID_MASK)
> > >    332                        return -EINVAL;
> > >    333                switch (response & FANOTIFY_RESPONSE_ACCESS) {
> > >    334                case FAN_ALLOW:
> > >    335                case FAN_DENY:
> > >    336                        break;
> > >    337                default:
> > >    338                        return -EINVAL;
> > >    339                }
> > >    340                if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT))
> > >    341                        return -EINVAL;
> > >    342                if (fd < 0)
> > >    343                        return -EINVAL;
> > >    344                if (response & FAN_INFO) {
> > >    345                        size_t c = count;
> > >    346                        const char __user *ib = buf;
> > >    347
> > >    348                        if (c <= 0)
> > >    349                                return -EINVAL;
> > >    350                        while (c >= sizeof(info_hdr)) {
> > >    351                                if (copy_from_user(&info_hdr, ib, sizeof(info_hdr)))
> > >    352                                        return -EFAULT;
> > >    353                                if (info_hdr.pad != 0)
> > >    354                                        return -EINVAL;
> > >    355                                if (c < info_hdr.len)
> > >    356                                        return -EINVAL;
> > >    357                                switch (info_hdr.type) {
> > >    358                                case FAN_RESPONSE_INFO_AUDIT_RULE:
> > >    359                                        break;
> > >    360                                case FAN_RESPONSE_INFO_NONE:
> > >    361                                default:
> > >    362                                        return -EINVAL;
> > >    363                                }
> > >    364                                c -= info_hdr.len;
> > >    365                                ib += info_hdr.len;
> > >    366                        }
> > >    367                        if (c != 0)
> > >    368                                return -EINVAL;
> > >    369                        /* Simplistic check for now */
> > >    370                        if (count != sizeof(struct fanotify_response_info_audit_rule))
> > >    371                                return -EINVAL;
> > >    372                        info_buf = kmalloc(sizeof(struct fanotify_response_info_audit_rule),
> > >    373                                           GFP_KERNEL);
> > >    374                        if (!info_buf)
> > >    375                                return -ENOMEM;
> > >    376                        if (copy_from_user(info_buf, buf, count))
> > >    377                                return -EFAULT;
> > >    378                }
> > >    379                spin_lock(&group->notification_lock);
> > >    380                list_for_each_entry(event, &group->fanotify_data.access_list,
> > >    381                                    fae.fse.list) {
> > >    382                        if (event->fd != fd)
> > >    383                                continue;
> > >    384
> > >    385                        list_del_init(&event->fae.fse.list);
> > >    386                        /* finish_permission_event() eats info_buf */
> > >    387                        finish_permission_event(group, event, response_struct,
> > >    388                                                count, info_buf);
> > >    389                        wake_up(&group->fanotify_data.access_waitq);
> > >    390                        return 0;
> > >    391                }
> > >    392                spin_unlock(&group->notification_lock);
> > >    393
> > >    394                return -ENOENT;
> > >    395        }
> > >    396
> > >
> > > --
> > > 0-DAY CI Kernel Test Service
> > > https://01.org/lkp
> > >
> >
> > - RGB
> >
> > --
> > Richard Guy Briggs <rgb@redhat.com>
> > Sr. S/W Engineer, Kernel Security, Base Operating Systems
> > Remote, Ottawa, Red Hat Canada
> > IRC: rgb, SunRaycer
> > Voice: +1.647.777.2635, Internal: (81) 32635
> >
> >
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers
> 

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635