Re: [PATCH v13 7/9] open: openat2(2) syscall

From: kbuild test robot
Date: Tue Oct 01 2019 - 01:07:16 EST


Hi Aleksa,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.4-rc1 next-20191001]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url: https://github.com/0day-ci/linux/commits/Aleksa-Sarai/namei-openat2-2-path-resolution-restrictions/20191001-025628
reproduce:
# apt-get install sparse
# sparse version: v0.6.1-rc1-37-gd466a02-dirty
make ARCH=x86_64 allmodconfig
make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>


sparse warnings: (new ones prefixed by >>)

fs/open.c:757:13: sparse: sparse: restricted fmode_t degrades to integer
fs/open.c:983:18: sparse: sparse: restricted fmode_t degrades to integer
>> fs/open.c:1011:36: sparse: sparse: invalid assignment: |=
>> fs/open.c:1011:36: sparse: left side has type int
>> fs/open.c:1011:36: sparse: right side has type restricted fmode_t
fs/open.c:1013:36: sparse: sparse: invalid assignment: |=
fs/open.c:1013:36: sparse: left side has type int
fs/open.c:1013:36: sparse: right side has type restricted fmode_t
>> fs/open.c:1029:24: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted fmode_t [usertype] opath_mask @@ got pe] opath_mask @@
>> fs/open.c:1029:24: sparse: expected restricted fmode_t [usertype] opath_mask
>> fs/open.c:1029:24: sparse: got int opath_mask
>> fs/open.c:1011:36: sparse: sparse: invalid assignment: |=
>> fs/open.c:1011:36: sparse: left side has type int
>> fs/open.c:1011:36: sparse: right side has type restricted fmode_t
fs/open.c:1013:36: sparse: sparse: invalid assignment: |=
fs/open.c:1013:36: sparse: left side has type int
fs/open.c:1013:36: sparse: right side has type restricted fmode_t
>> fs/open.c:1029:24: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted fmode_t [usertype] opath_mask @@ got pe] opath_mask @@
>> fs/open.c:1029:24: sparse: expected restricted fmode_t [usertype] opath_mask
>> fs/open.c:1029:24: sparse: got int opath_mask
>> fs/open.c:1011:36: sparse: sparse: invalid assignment: |=
>> fs/open.c:1011:36: sparse: left side has type int
>> fs/open.c:1011:36: sparse: right side has type restricted fmode_t
fs/open.c:1013:36: sparse: sparse: invalid assignment: |=
fs/open.c:1013:36: sparse: left side has type int
fs/open.c:1013:36: sparse: right side has type restricted fmode_t
>> fs/open.c:1029:24: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted fmode_t [usertype] opath_mask @@ got pe] opath_mask @@
>> fs/open.c:1029:24: sparse: expected restricted fmode_t [usertype] opath_mask
>> fs/open.c:1029:24: sparse: got int opath_mask
fs/open.c:1173:15: sparse: sparse: undefined identifier 'copy_struct_from_user'

vim +1011 fs/open.c

957
958 static inline int build_open_flags(const struct open_how *how,
959 struct open_flags *op)
960 {
961 int flags = how->flags;
962 int lookup_flags = 0;
963 int opath_mask = 0;
964 int acc_mode = ACC_MODE(flags);
965
966 /*
967 * Older syscalls still clear these bits before calling
968 * build_open_flags(), but openat2(2) checks all its arguments.
969 */
970 if (flags & ~VALID_OPEN_FLAGS)
971 return -EINVAL;
972 if (how->resolve & ~VALID_RESOLVE_FLAGS)
973 return -EINVAL;
974 if (!(how->flags & (O_PATH | O_CREAT | __O_TMPFILE)) && how->mode != 0)
975 return -EINVAL;
976
977 if (flags & (O_CREAT | __O_TMPFILE))
978 op->mode = (how->mode & S_IALLUGO) | S_IFREG;
979 else
980 op->mode = 0;
981
982 /* Must never be set by userspace */
> 983 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
984
985 /*
986 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
987 * check for O_DSYNC if the need any syncing at all we enforce it's
988 * always set instead of having to deal with possibly weird behaviour
989 * for malicious applications setting only __O_SYNC.
990 */
991 if (flags & __O_SYNC)
992 flags |= O_DSYNC;
993
994 if (flags & __O_TMPFILE) {
995 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
996 return -EINVAL;
997 if (!(acc_mode & MAY_WRITE))
998 return -EINVAL;
999 } else if (flags & O_PATH) {
1000 /*
1001 * If we have O_PATH in the open flag. Then we
1002 * cannot have anything other than the below set of flags
1003 */
1004 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
1005 acc_mode = 0;
1006
1007 /* Allow userspace to restrict the re-opening of O_PATH fds. */
1008 if (how->upgrade_mask & ~VALID_UPGRADE_FLAGS)
1009 return -EINVAL;
1010 if (!(how->upgrade_mask & UPGRADE_NOREAD))
> 1011 opath_mask |= FMODE_PATH_READ;
1012 if (!(how->upgrade_mask & UPGRADE_NOWRITE))
1013 opath_mask |= FMODE_PATH_WRITE;
1014 }
1015
1016 op->open_flag = flags;
1017
1018 /* O_TRUNC implies we need access checks for write permissions */
1019 if (flags & O_TRUNC)
1020 acc_mode |= MAY_WRITE;
1021
1022 /* Allow the LSM permission hook to distinguish append
1023 access from general write access. */
1024 if (flags & O_APPEND)
1025 acc_mode |= MAY_APPEND;
1026
1027 op->acc_mode = acc_mode;
1028 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
> 1029 op->opath_mask = opath_mask;
1030
1031 if (flags & O_CREAT) {
1032 op->intent |= LOOKUP_CREATE;
1033 if (flags & O_EXCL)
1034 op->intent |= LOOKUP_EXCL;
1035 }
1036
1037 if (flags & O_DIRECTORY)
1038 lookup_flags |= LOOKUP_DIRECTORY;
1039 if (!(flags & O_NOFOLLOW))
1040 lookup_flags |= LOOKUP_FOLLOW;
1041 if (flags & O_EMPTYPATH)
1042 lookup_flags |= LOOKUP_EMPTY;
1043
1044 if (how->resolve & RESOLVE_NO_XDEV)
1045 lookup_flags |= LOOKUP_NO_XDEV;
1046 if (how->resolve & RESOLVE_NO_MAGICLINKS)
1047 lookup_flags |= LOOKUP_NO_MAGICLINKS;
1048 if (how->resolve & RESOLVE_NO_SYMLINKS)
1049 lookup_flags |= LOOKUP_NO_SYMLINKS;
1050 if (how->resolve & RESOLVE_BENEATH)
1051 lookup_flags |= LOOKUP_BENEATH;
1052 if (how->resolve & RESOLVE_IN_ROOT)
1053 lookup_flags |= LOOKUP_IN_ROOT;
1054
1055 op->lookup_flags = lookup_flags;
1056 return 0;
1057 }
1058

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