On Mon, Sep 11, 2023 at 9:19 AM Stephen Smalley stephen.smalley.work@gmail.com wrote:
On Fri, Sep 8, 2023 at 6:54 PM kernel test robot lkp@intel.com wrote:
Hi Alfred,
kernel test robot noticed the following build errors:
[auto build test ERROR on 50a510a78287c15cee644f345ef8bac8977986a7]
url: https://github.com/intel-lab-lkp/linux/commits/Alfred-Piccioni/SELinux-Check... base: 50a510a78287c15cee644f345ef8bac8977986a7 patch link: https://lore.kernel.org/r/20230906115928.3749928-1-alpic%40google.com patch subject: [PATCH V2] SELinux: Check correct permissions for FS_IOC32_* config: i386-debian-10.3 (https://download.01.org/0day-ci/archive/20230909/202309090600.NSyo7d2q-lkp@i...) 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/20230909/202309090600.NSyo7d2q-lkp@i...)
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/202309090600.NSyo7d2q-lkp@intel.com/
All errors (new ones prefixed by >>):
security/selinux/hooks.c: In function 'selinux_file_ioctl':
security/selinux/hooks.c:3647:9: error: duplicate case value
3647 | case FS_IOC32_GETFLAGS: | ^~~~security/selinux/hooks.c:3645:9: note: previously used here 3645 | case FS_IOC_GETFLAGS: | ^~~~ security/selinux/hooks.c:3648:9: error: duplicate case value 3648 | case FS_IOC32_GETVERSION: | ^~~~ security/selinux/hooks.c:3646:9: note: previously used here 3646 | case FS_IOC_GETVERSION: | ^~~~ security/selinux/hooks.c:3654:9: error: duplicate case value 3654 | case FS_IOC32_SETFLAGS: | ^~~~ security/selinux/hooks.c:3652:9: note: previously used here 3652 | case FS_IOC_SETFLAGS: | ^~~~ security/selinux/hooks.c:3655:9: error: duplicate case value 3655 | case FS_IOC32_SETVERSION: | ^~~~ security/selinux/hooks.c:3653:9: note: previously used here 3653 | case FS_IOC_SETVERSION: | ^~~~
Not sure of the right way to fix this while addressing the original issue that this patch was intended to fix. Looking in fs/ioctl.c, I see that the some FS_IOC32 values are remapped to the corresponding FS_IOC values by the compat ioctl syscall entrypoint. Also notice this comment there:
/* RED-PEN how should LSM module know it's handling 32bit? */ error = security_file_ioctl(f.file, cmd, arg); if (error) goto out;So perhaps this is a defect in LSM that needs to be addressed?
Note btw that some of the 32-bit ioctl commands are only handled in the fs-specific compat_ioctl routines, e.g. ext4_compat_ioctl() handles EXT4_IOC32_GETVERSION == FS_IOC32_GETVERSION and ditto for _SETVERSION.
vim +3647 security/selinux/hooks.c
3634 3635 static int selinux_file_ioctl(struct file *file, unsigned int cmd, 3636 unsigned long arg) 3637 { 3638 const struct cred *cred = current_cred(); 3639 int error = 0; 3640 3641 switch (cmd) { 3642 case FIONREAD: 3643 case FIBMAP: 3644 case FIGETBSZ: 3645 case FS_IOC_GETFLAGS: 3646 case FS_IOC_GETVERSION:
3647 case FS_IOC32_GETFLAGS:
3648 case FS_IOC32_GETVERSION: 3649 error = file_has_perm(cred, file, FILE__GETATTR); 3650 break; 3651 3652 case FS_IOC_SETFLAGS: 3653 case FS_IOC_SETVERSION: 3654 case FS_IOC32_SETFLAGS: 3655 case FS_IOC32_SETVERSION: 3656 error = file_has_perm(cred, file, FILE__SETATTR); 3657 break; 3658 3659 /* sys_ioctl() checks */ 3660 case FIONBIO: 3661 case FIOASYNC: 3662 error = file_has_perm(cred, file, 0); 3663 break; 3664 3665 case KDSKBENT: 3666 case KDSKBSENT: 3667 error = cred_has_capability(cred, CAP_SYS_TTY_CONFIG, 3668 CAP_OPT_NONE, true); 3669 break; 3670 3671 case FIOCLEX: 3672 case FIONCLEX: 3673 if (!selinux_policycap_ioctl_skip_cloexec()) 3674 error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); 3675 break; 3676 3677 /* default case assumes that the command will go 3678 * to the file's ioctl() function. 3679 */ 3680 default: 3681 error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); 3682 } 3683 return error; 3684 } 3685