NetCube-Systems-Austria/kumquat-buildroot
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system: allow/disallow root login, accept encoded passwords

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Currently, there are only two possibilities regarding the root account:
  - it is enabled with no password (the default)
  - it is enabled, using a clear-text, user-provided password

This is deemed insufficient in many cases, especially when the .config
file has to be published (e.g. for the GPL compliance, or any other
reason.).

Fix that in two ways:

  - add a boolean option that allows/disallows root login altogether,
    which defaults to 'y' to keep backward compatibility;

  - accept already-encoded passwords, which we recognise as starting
    with either of $1$, $5$ or $6$ (resp. for md5, sha256 or sha512).

Signed-off-by: Lorenzo M. Catucci <lorenzo@sancho.ccd.uniroma2.it>
[yann.morin.1998@free.fr:
  - don't add a choice to select between clear-text/encoded password,
    use a single prompt;
  - differentiate in the password hook itself;
  - rewrite parts of the help entry;
  - rewrite and expand the commit log
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Tested-by: "Lorenzo M. Catucci" <lorenzo@sancho.ccd.uniroma2.it>
Acked-by: "Lorenzo M. Catucci" <lorenzo@sancho.ccd.uniroma2.it>
Tested-by: Gergely Imreh <imrehg@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
This commit is contained in:
Lorenzo Catucci 2015-07-02 22:00:05 +02:00 committed by Thomas Petazzoni
parent 9a42ba3eeb
commit 18fa4a32a6
2 changed files with 44 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
system/Config.in
View File

@ -176,26 +176,43 @@ endif
if BR2_ROOTFS_SKELETON_DEFAULT
config BR2_TARGET_ENABLE_ROOT_LOGIN
bool "Enable root login with password"
default y
help
Allow root to log in with a password.
If not enabled, root will not be able to log in with a password.
However, if you have an ssh server and you add an ssh key, you
can still allow root to log in. Alternatively, you can use sudo
to become root.
config BR2_TARGET_GENERIC_ROOT_PASSWD
string "Root password"
default ""
depends on BR2_TARGET_ENABLE_ROOT_LOGIN
help
Set the initial root password (in clear). It will be md5-encrypted.
Set the initial root password.
If set to empty (the default), then no root password will be set,
and root will need no password to log in.
WARNING! WARNING!
Although pretty strong, MD5 is now an old hash function, and
suffers from some weaknesses, which makes it susceptible to attacks.
It is showing its age, so this root password should not be trusted
to properly secure any product that can be shipped to the wide,
hostile world.
If the password starts with any of $1$, $5$ or $6$, it is considered
to be already crypt-encoded with respectively md5, sha256 or sha512.
Any other value is taken to be a clear-text value, and is crypt-encoded
as per the "Passwords encoding" scheme, above.
Note: "$" signs in the hashed password must be doubled. For example,
if the hashed password is "$1$longsalt$v35DIIeMo4yUfI23yditq0",
then you must enter it as "$$1$$longsalt$$v35DIIeMo4yUfI23yditq0"
(this is necessary otherwise make would attempt to interpret the $
as a variable expansion).
WARNING! WARNING!
The password appears in clear in the .config file, and may appear
The password appears as-is in the .config file, and may appear
in the build log! Avoid using a valuable password if either the
.config file or the build log may be distributed!
.config file or the build log may be distributed, or at the
very least use a strong cryptographic hash for your password!
choice
bool "/bin/sh"

27
system/system.mk
View File

@ -34,10 +34,6 @@ endef
TARGET_FINALIZE_HOOKS += SYSTEM_ISSUE
endif
ifneq ($(TARGET_GENERIC_ROOT_PASSWD),)
PACKAGES += host-mkpasswd
endif
define SET_NETWORK_LOCALHOST
( \
echo "# interface file auto-generated by buildroot"; \
@ -69,12 +65,25 @@ TARGET_FINALIZE_HOOKS += SET_NETWORK
ifeq ($(BR2_ROOTFS_SKELETON_DEFAULT),y)
define SYSTEM_ROOT_PASSWD
[ -n "$(TARGET_GENERIC_ROOT_PASSWD)" ] && \
TARGET_GENERIC_ROOT_PASSWD_HASH=$$($(MKPASSWD) -m "$(TARGET_GENERIC_PASSWD_METHOD)" "$(TARGET_GENERIC_ROOT_PASSWD)"); \
$(SED) "s,^root:[^:]*:,root:$$TARGET_GENERIC_ROOT_PASSWD_HASH:," $(TARGET_DIR)/etc/shadow
ifeq ($(BR2_TARGET_ENABLE_ROOT_LOGIN),y)
ifeq ($(TARGET_GENERIC_ROOT_PASSWD),)
SYSTEM_ROOT_PASSWORD =
else ifneq ($(filter $$1$$% $$5$$% $$6$$%,$(TARGET_GENERIC_ROOT_PASSWD)),)
SYSTEM_ROOT_PASSWORD = $(TARGET_GENERIC_ROOT_PASSWD)
else
PACKAGES += host-mkpasswd
# This variable will only be evaluated in the finalize stage, so we can
# be sure that host-mkpasswd will have already been built by that time.
SYSTEM_ROOT_PASSWORD = $(shell $(MKPASSWD) -m "$(TARGET_GENERIC_PASSWD_METHOD)" "$(TARGET_GENERIC_ROOT_PASSWD)")
endif
else # !BR2_TARGET_ENABLE_ROOT_LOGIN
SYSTEM_ROOT_PASSWORD = *
endif
define SYSTEM_SET_ROOT_PASSWD
$(SED) 's,^root:[^:]*:,root:$(SYSTEM_ROOT_PASSWORD):,' $(TARGET_DIR)/etc/shadow
endef
TARGET_FINALIZE_HOOKS += SYSTEM_ROOT_PASSWD
TARGET_FINALIZE_HOOKS += SYSTEM_SET_ROOT_PASSWD
ifeq ($(BR2_SYSTEM_BIN_SH_NONE),y)
define SYSTEM_BIN_SH