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authorGravatar Lorenzo Catucci <lorenzo@sancho.ccd.uniroma2.it>2015-07-02 22:00:05 +0200
committerGravatar Thomas Petazzoni <thomas.petazzoni@free-electrons.com>2015-07-04 12:46:43 +0200
commit18fa4a32a67372aa8f3949b5273d7b43dd4ad4f9 (patch)
treedc999b8a26df22a3d1f5875a6df85bc159c02b27 /system
parent9a42ba3eeba08e450762141be03156208f2b4de0 (diff)
downloadbuildroot-18fa4a32a67372aa8f3949b5273d7b43dd4ad4f9.tar.gz
buildroot-18fa4a32a67372aa8f3949b5273d7b43dd4ad4f9.tar.bz2
system: allow/disallow root login, accept encoded passwords
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>
Diffstat (limited to 'system')
-rw-r--r--system/Config.in35
-rw-r--r--system/system.mk27
2 files changed, 44 insertions, 18 deletions
diff --git a/system/Config.in b/system/Config.in
index 15f051561f..b72aa1781b 100644
--- a/system/Config.in
+++ b/system/Config.in
@@ -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$$v35DIIeMo4yUfI23yditq0"
+ (this is necessary otherwise make would attempt to interpret the $
+ as a variable expansion).
WARNING! WARNING!
- The password appears in clear in the .config file, and may appear
+ The password appears as-is in the .config file, and may appear
in the build log! Avoid using a valuable password if either the
- .config file or the build log may be distributed!
+ .config file or the build log may be distributed, or at the
+ very least use a strong cryptographic hash for your password!
choice
bool "/bin/sh"
diff --git a/system/system.mk b/system/system.mk
index c95e436c6e..279466741f 100644
--- a/system/system.mk
+++ b/system/system.mk
@@ -34,10 +34,6 @@ endef
TARGET_FINALIZE_HOOKS += SYSTEM_ISSUE
endif
-ifneq ($(TARGET_GENERIC_ROOT_PASSWD),)
-PACKAGES += host-mkpasswd
-endif
-
define SET_NETWORK_LOCALHOST
( \
echo "# interface file auto-generated by buildroot"; \
@@ -69,12 +65,25 @@ TARGET_FINALIZE_HOOKS += SET_NETWORK
ifeq ($(BR2_ROOTFS_SKELETON_DEFAULT),y)
-define SYSTEM_ROOT_PASSWD
- [ -n "$(TARGET_GENERIC_ROOT_PASSWD)" ] && \
- TARGET_GENERIC_ROOT_PASSWD_HASH=$$($(MKPASSWD) -m "$(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