使用新的 ssh 登录：
$ umask
0007
但：
$ find . -maxdepth 1 -name '.*' -type f | xargs grep 007 | less
$
# grep 007 /etc/profile
#
# grep -i umask /etc/login.defs
# UMASK Default "umask" value.
# UMASK is the default umask value for pam_umask and is used by
# 022 is the "historical" value in Debian for UMASK
UMASK 027
# Other former uses of this variable such as setting the umask when
# grep -i umask /etc/pam.d/common-session
session optional pam_umask.so usergroups
什么鬼？Debian发明任意的 umask?? 并且 /etc 中没有其他源与 007 匹配！
系统使用 LDAP（nscld、pam_ldap）进行身份验证
更多信息：这种情况只发生在一个用户身上。不发生在 root 或其他用户身上。当我“su”到这个用户时，我再次得到 007。
以 root 身份：
# strace -f -o basz.log su baduser
有一些东西正在设置这个 umask 但我不知道是什么：
[...]
2622 open("/etc/group", O_RDONLY|O_CLOEXEC) = 4
2622 _llseek(4, 0, [0], SEEK_CUR) = 0
2622 fstat64(4, {st_mode=S_IFREG|0644, st_size=1719, ...}) = 0
2622 mmap2(NULL, 1719, PROT_READ, MAP_SHARED, 4, 0) = 0xb7786000
2622 _llseek(4, 1719, [1719], SEEK_SET) = 0
2622 fstat64(4, {st_mode=S_IFREG|0644, st_size=1719, ...}) = 0
2622 munmap(0xb7786000, 1719) = 0
2622 close(4) = 0
2622 socket(PF_FILE, SOCK_STREAM, 0) = 4
2622 connect(4, {sa_family=AF_FILE, path="/var/run/nslcd/socket"}, 23) = 0
2622 gettimeofday({1404702848, 321946}, NULL) = 0
2622 gettimeofday({1404702848, 322029}, NULL) = 0
2622 poll([{fd=4, events=POLLOUT}], 1, 10000) = 1 ([{fd=4, revents=POLLOUT}])
2622 send(4, "\1\0\0\0\212\23\0\0\361\3\0\0", 12, MSG_NOSIGNAL) = 12
2622 gettimeofday({1404702848, 322363}, NULL) = 0
2622 gettimeofday({1404702848, 322464}, NULL) = 0
2622 poll([{fd=4, events=POLLIN}], 1, 60000) = 1 ([{fd=4, revents=POLLIN|POLLHUP}])
2622 read(4, "\1\0\0\0\212\23\0\0\0\0\0\0\4\0\0\0baduser\1\0\0\0*\361\3\0\0\2\0\0"..., 1024) = 57
2622 gettimeofday({1404702848, 323811}, NULL) = 0
2622 gettimeofday({1404702848, 323898}, NULL) = 0
2622 gettimeofday({1404702848, 323983}, NULL) = 0
2622 gettimeofday({1404702848, 324067}, NULL) = 0
2622 gettimeofday({1404702848, 324170}, NULL) = 0
2622 gettimeofday({1404702848, 324256}, NULL) = 0
2622 gettimeofday({1404702848, 324340}, NULL) = 0
2622 gettimeofday({1404702848, 324434}, NULL) = 0
2622 gettimeofday({1404702848, 324518}, NULL) = 0
2622 gettimeofday({1404702848, 324602}, NULL) = 0
2622 gettimeofday({1404702848, 324686}, NULL) = 0
2622 gettimeofday({1404702848, 324772}, NULL) = 0
2622 poll([{fd=4, events=POLLIN}], 1, 0) = 1 ([{fd=4, revents=POLLIN|POLLHUP}])
2622 read(4, "", 1024) = 0
2622 gettimeofday({1404702848, 325036}, NULL) = 0
2622 close(4) = 0
2622 umask(0777) = 027
2622 umask(07) = 0777
[...]
更多信息：
- 如果我在 /etc/profile 中写入“umask 0027”，它也能正常工作！
- 如果我删除主目录并重新创建它，问题仍然存在
答案1
答案是：
man pam_umask
usergroups
If the user is not root, and the user ID is equal to the group ID, and the
username is the same as primary group name, the umask group bits are set to
be the same as owner bits (examples: 022 -> 002, 077 -> 007).
男人 ...