De onde o Debian pega o umask padrão?

Question

Com um novo login no ssh:

$ umask
0007

Mas:

$ 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

WTF? Debian inventa umask arbitrária ?? E não há outra fonte em / etc que corresponda a 007!

O sistema usa LDAP (nscld, pam_ldap) para autenticação

Mais informações: isso acontece apenas para um usuário. Não é para root ou um usuário diferente. Assim que eu 'su' para o usuário eu recebo novamente 007.

Como root:

# strace -f -o basz.log su baduser

Algo está configurando essa umask, mas não sei o que:

[...]
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, "
$ umask
0007
$ 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
# strace -f -o basz.log su baduser
2
[...]
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, "%pre%%pre%%pre%2%pre%%pre%1%pre%%pre%", 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, "%pre%%pre%%pre%2%pre%%pre%%pre%%pre%%pre%%pre%%pre%%pre%%pre%baduser%pre%%pre%%pre%*1%pre%%pre%%pre%%pre%"..., 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
[...]
%pre%1%pre%%pre%", 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, "%pre%%pre%%pre%2%pre%%pre%%pre%%pre%%pre%%pre%%pre%%pre%%pre%baduser%pre%%pre%%pre%*1%pre%%pre%%pre%%pre%"..., 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
[...]

Mais informações:

• Se eu escrever "umask 0027" no / etc / profile, ele também funciona!
• Se eu remover o diretório inicial e recriá-lo, o problema persistirá

Answer 1

A resposta é:

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). 

Homem ...